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Amalgam past,present & future-2

The document discusses the manipulation of dental amalgam, including the selection of alloy, mercury to alloy ratio, methods of proportioning and mixing the amalgam. It describes hand mixing versus mechanical mixing in a device called an amalgamator. The ideal mercury to alloy ratio is 1:1 or 50% mercury. Mechanical mixing provides standardization and requires less mixing time than hand mixing. Both under-mixing and over-mixing can affect the properties of the set amalgam. Mulling is described as a continuation of mixing to produce a coherent and homogenous mix. Condensation of the amalgam into the prepared cavity is also briefly mentioned.

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POSTGRADUATE DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS SEMINAR TOPIC:- DENTAL AMALGAMPAST,PRESENT & FUTURE-II (TECHNICAL CONSIDERATIONS, PRESENT SCENARIO & FUTURE) Presented by- Ashish Choudhary Pg student UNDER GUIDANCE OF :- Prof. Dr Riyaz Farooq (HOD) Dr Aamir Rashid (lecturer) Dr Fayaz Ahmed (lecturer) 1
Contents  Introduction  History of amalgam  Amalgam wars  Classification  Components of amalgam  Basic setting reaction  Manufacture of alloy powder  Properties of amalgam  Manipulation of amalgam  Recent advances in amalgam  Side effects of mercury  Durability of amalgam  Future of amalgam  Conclusion 2
MANIPULATION OF DENTAL AMALGAM 3
Selection of alloy 4
Selection of alloy  involves a number of factors, including setting time, particle size & shape & composition, particularly as it relates to the elimination of the γ2 phase & the presence or absence of zinc Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion More than 90% of the dental amalgams currently placed are high copper alloys including spherical & admixed types 5 Phillip’s Science of Dental Materials;11th ed
Selection of alloy mainly aims at High one hour strength Minimum dimensional change Lowest creep value Good condensing property High corrosion resistance Good polishing and finishing abilities Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 6
Mercury /alloy ratio • Important variable 7
Mercury/alloy ratio • Earlier excess mercury was used to achieve smooth & plastic amalgam mix • This excess Hg was removed from the amalgam by:1. Squeezing the excess Hg out by using squeeze cloth before insertion of increments in the prepared cavity 2. Increasing dryness technique Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 8 Phillip’s Science of Dental Materials;11th ed
Eames minimal mercury technique Recommended ratio→ 1:1→ 50% Hg Lathe cut alloys =50% Spherical alloys = 42% Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion produce a workable mass 9 Phillip’s Science of Dental Materials;11th ed
• VARIOUS METHODS – PROPORTIONING PREWEIGHED TABLET : specific weight of powder with appropriate Hg is dispensed into mixing capsule • proportion– by wt – not by volume • %Hg can be adjusted from 48-55%. DISPENSERS : accommodate 2 containers • 1- having Hg; • 2 – powder. • specific volume of powder & Hg - dispensed Into capsule. • proportion– by volume – not by wt Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 10 Phillip’s Science of Dental Materials;11th ed
• DISPOSABLE CAPSULES • SELF ACTIVATING CAPSULES • Reusable capsules • Preamalgamated alloys 11 Sturdevant’s Art & Science of Operative Dentistry;5th ed
SIZE OF MIX Capsules containing 400, 600 or 800mg of alloy and the appropriate Hg are available Colour coded for easy identification of capsules. • • • • 400mg - single mix. 600mg – single mix. 800mg – double mix 1200mg – for amalgam core Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 14 CRAIG’s Restorative Dental Materials;12th ed
TRITURATION 15
TRITURATION • Defined as process of grinding powder, esp. within a liquid. In dentistry, the term is used to describe the process of mixing the amalgam alloy particles with mercury in an amalgamator (as given in Phillip’s , 11th edn) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 16 Phillip’s Science of Dental Materials;11th ed
• Objective:-to wet all the surfaces of the alloy particles with Hg -for proper wetting, the alloy surface should be clean Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion -rubbing of the particles mechanically removes the oxide film coating on alloy particles 17 Phillip’s Science of Dental Materials;11th ed
• Trituration is achieved either by : A) Hand mixing B) Mechanical mixing Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 18 Phillip’s Science of Dental Materials;11th ed
v HAND TRITURATION MORTAR PESTLE Roughened inner surface, maintained by carborundum paste Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion glass rod with a round end 19 Phillip’s Science of Dental Materials;11th ed
• The 3 factors to obtain a well mixed amalgam mass are: 1. Number of rotations 2. Speed of rotation Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3. Magnitude of pressure placed on the pestle. Typically a 25-45 seconds period is sufficient 20 Phillip’s Science of Dental Materials;11th ed
Mechanical trituration • Trituration of alloy & Hg is done with a mechanical mixing device called an “amalgamator or triturator” • The disposable capsule serves as a mortar Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • a cylindrical metal or plastic piston is placed in the capsule which serve as a pestle 21 Phillip’s Science of Dental Materials;11th ed
AMALGAMATORS FOR MECHANICAL TRITURATION SPEED TIME The speed used is recommended by the manufacturer. High ENERGY = Speed higher copper alloys require x Time mixing speeds The capsule is inserted b/w the armscapsule oscillate at When amalgamatorsarms automaticthe on speed of the The put on, the have holding timer &3800,top - 40- 4400 low speed 32 -3400cycles/min, medium - 37high 22 machines device triturating the amalgam high speed, thus control
• Using a parameter called coherence time (tc), defined as the minimum mixing time required for an amalgam to form a single coherent pellet, it has been found that the compressive strength, dimensional change & creep are optimized if mixing is carried out for a time of 5tc. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 23 Phillip’s Science of Dental Materials;11th ed
MIXING TIME --spherical alloys usually require less amalgamation time than lathe cut alloys --a large mix requires slightly longer mixing time than a smaller one Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 24 Phillip’s Science of Dental Materials;11th ed
• Advantages of mechanical trituration: 1.Shorter mixing time 2.More standardized procedure Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3.Require less mercury when compared to hand mixing technique 25 Phillip’s Science of Dental Materials;11th ed
MECHANICAL TRITURATION 26
Undertriturated mix        is rough & grainy may crumble mix hardens too rapidly excess mercury will remain gives a rough surface after carving tarnish & corrosion may occur less strength Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 27 Phillip’s Science of Dental Materials;11th ed
NORMAL MIX  shiny surface smooth & soft consistency  warm, when removed from the capsule best compressive & tensile strength increased resistance to tarnish & corrosion Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 28 Phillip’s Science of Dental Materials;11th ed
Overtriturated mix Soupy mix difficult to remove from the capsule too plastic to manipulate decreased working time higher contraction of amalgam strength of lathecut alloys is increased, whereas it is reduced in high copper alloys increased creep Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 29 Phillip’s Science of Dental Materials;11th ed
MULLING • Continuation of trituration • Hand mulling  Dry piece of rubber dam or glove  Rubbed between the first finger and thumb  2 to 5 seconds. • Mechanical mulling mix is retriturated in an pestle free capsule for an addtional 2-3 sec • Advantages Coherent, consistent and homogenous mix Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 30
CONDENSATION 31
CONDENSATION • The amalgam is placed in the cavity after trituration & the packed (condensed) using suitable instruments • Goal of condensation-is to compact the alloy into the prepared cavity so that the greatest possible density is achieved, with sufficient Hg to ensure complete continuity of the matrix phase(Ag2Hg3) b/w the remaining alloy particles Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 32 Phillip’s Science of Dental Materials;11th ed
Aims of condensation 1. to secure adaptation of the amalgam to the walls and the margins 2. to get compactness and homogeneity of the amalgam in the restoration with minimal voids Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3. Remove the excess mercury 33 Phillip’s Science of Dental Materials;11th ed
Modes of condensation Manual condensation Mechanical condensation Pneumatic Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Electrical 34
Condensers  Are instruments with serrated tips of different shapes & sizes  The shapes are oval, crescent, trapezoidal, triangular, circular or square Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion  Condenser type is selected as per the area & shape of the cavity  Smaller the condenser, greater is the pressure exerted on the amalgam 35 Phillip’s Science of Dental Materials;11th ed
Condensation technique • The field of operation should be kept absolutely dry during condensation The amalgam should be carried to the cavity with amalgam carrier incrementally Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Immediate condensation done after each increment with sufficient pressure (3-4 pounds) in vertical and horizontal direction starting with smaller condenser 36 Phillip’s Science of Dental Materials;11th ed
• The condensation is started at the center & the condenser point is stepped little by little towards the cavity walls The procedure of adding an increment and condensing it, adding another increment is continued until the cavity is overfilled (about 1mm) and the filling is over packed with larger condenser Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Explorer tine to scrap the BLOTTING MIX marginal ridge 37 Phillip’s Science of Dental Materials;11th ed
GENERAL GUIDELINES Modern amalgams are fast setting & so working time is short A fresh mix of amalgam should be ready if condensation takes more than 3-4 minutes Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion After condensation of each increment –remove any excess Hg 15 lbs of pres. of condensation recommended Avg force used is 3-4 lbs (13.3 – 17.8 N) 38 Phillip’s Science of Dental Materials;11th ed
LATHE CUT AMALGAM SPHERICAL AMALGAM Small High force condensers ADMIXED AMALGAM Low Hg/alloy ratio Less condensation force req. Larger condensers Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion intermediate handling between More lateral and spherical lathe-cut condensation 39 Phillip’s Science of Dental Materials;11th ed
CONDENSATION PROCEDURE 40
Precarving burnishing • Form of condensation to ensure dense amalgam at the margins & aids in shaping of the restoration Heavy stroke with large burnisher moving from the center of the restoration outwards beyond the margins Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion As crystallization of amalgam occurs, it's consistency becomes much stiffer, it is suitable for carving 41 Phillip’s Science of Dental Materials;11th ed
CARVING 42
CARVING OF AMALGAM Initial carving consist of removal of the bulk excess using a large spoon excavator OBJECTIVES: Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion no undercuts proper physiological contours minimal flash functional, non-interfering occlusal anatomy Adequate, compatible marginal ridges Proper size, location, extent & interrelationship of contact areas Preserving Biological width 43 Phillip’s Science of Dental Materials;11th ed
The carving should not be started untill amalgam is hard enough to be carved scrapping or ringing sound CARVING INSTRUMENTS: 1.Cleoid-Discoid Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 2.Spoon Excavator 3.Hollenback 4.Wards 5.Diamond shaped 44 Phillip’s Science of Dental Materials;11th ed
CARVING TECHNIQUE Select an acorn burnisher that will be wide enough to ride the isthmus without entering the preparation After condensation induce heavy pressure through out the length of the central and developmental grooves Strokes – from tooth to amalgam surface, or laterally along tooth – amalgam interface Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion All accessible embrasures established in restoration- sharp explorer or lateral edges of hollenback carver 45 JPD 1981;VOL46;NO.5
Create triangular fossae – discoid, cleiod carvers, diamond shaped carver Define marginal ridges – sharp explorer Carver moves parallel to the margin Carver should rest on enamel as well as amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Surface is rendered smooth and free of gross excess material by using a tightly twisted cotton 46 JPD 1981;VOL46;NO.5
Guidelines for carving Pulling strokes – mostly Pushing stroke - developing occlusal anatomy Occlusal anatomy should be kept reasonably (shallow) to preserve a bulk of amalgam at the margin 75 – 90 angle at the margin of occlusal amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Mesial and distal pit areas should be carved slightly deeper than the proximal marginal ridge Undercarving leads to amalgams grown out appearance 47
CARVING PROCEDURE 48
POSTCARVE BURNISHING 49
Burnishing of amalgam • it is a light rubbing of the carved surface with the burnisher to improve smoothness & produce a shiny appearance & produce a denser amalgam with more compaction , adaptation and sealing of amalgam at the margins Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 50 Phillip’s Science of Dental Materials;11th ed
Burnishing is done with a ball burnisher using light stroke proceeding from the amalgam surface to the tooth surface Heavy forces should not be used Brings excess Hg to surface – discarded If the temperature rises above 60 ͦC, mercury is released which may cause corrosion & fracture at the margins Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Pre carving and post carving burnishing > only Pre or post carving burnishing Dental Materials, Volume 3, Issue 3, June 1987, Pages 117-120 51 Phillip’s Science of Dental Materials;11th ed
light closer is made and the surface checked for the heavier burnished areas, lateral slide is used to develop the desired eccentric occlusion Articulating paper may be used to check the occlusion Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Finally the grooves are enhanced with "conical amalgam burnisher" and the amalgam is smoothened by a small damp ball of cotton 52 Phillip’s Science of Dental Materials;11th ed
FINISHING & POLISHING 53
Finishing & Polishing • is necessary to complete the carving, to refine the anatomy, contours, and marginal integrity and enhance the surface finishing of the restoration • they reduce the surface roughness of the restoration with less prone to tarnish and corrosion Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 54 Phillip’s Science of Dental Materials;11th ed
AFTER INITIAL SETTING Prophy cup with pumice provides initial smoothness to restorations Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 55 Phillip’s Science of Dental Materials;11th ed
FINAL POLISHING Done only after amalgam sets, delayed at least 24 hrs following condensation High Cu single composition spherical alloy: 8 min after trituration Always - low speed, low pressurevelvet finish AVOID UNDUE PRESSURE Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion USE ADEQUATE COOLING 56 CRAIG’s Restorative Dental Materials;12th ed
FINISHING& POLISHING instruments for amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Fig. From the left: five plain-cut plain steel finishing burs, two mounted stones, three mounted abrasive rubber points from coarse to fine, and a mounted abrasive rubber cup 57 Phillip’s Science of Dental Materials;11th ed
Finishing Discs Technique Use short, overlapping strokes and move diagonally across the cavosurface margins. Sequence Discs are used in a sequence of more abrasive to less abrasive grits. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Embrasures When using discs in embrasure areas, care must be taken not to damage the contact area or papilla. Phillip’s Science of Dental Materials;11th ed
Finishing strips a) Types : fine or medium b) Placed on both the tooth and the amalgam, and move in a back-and-forth motion. c) Avoid the contact area when using finishing strips, and use caution in areas of the inter dental papilla and surrounding tissue Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Wider strips may be cut in half lengthwise to make narrow strips 59 Phillip’s Science of Dental Materials;11th ed
Finishing burs/stones 1. Green stone to remove excess material and irregularities 2. Sequence largest bur →→ smaller and less abrasive burs 3. Technique Adapt the side of the bur or stone along the margin, contacting both tooth and amalgam. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 4. Direction of stroke Rotate the bur or stone from the amalgam to the tooth to avoid fracturing the amalgam margins. 5. Direction of work Always begin at the centre of the restoration and work toward the cavosurface margin 60 Phillip’s Science of Dental Materials;11th ed
POLISHING POINTS & RUBBER CUPS Abrasive-impregnated rubber cups & points are brownies in 3 colors super greenies Brown Green Yellow-banded green greenie USE Cups Points • • • - proximal surfaces Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion USED Each color denotes different degree of INTERCHANGEABLY - abrasiveness occlusal surface. relatively low speed light, intermittent strokes wet conditions. 61 Phillip’s Science of Dental Materials;11th ed
PUMICE is mixed with TIN OXIDE slurries rubber cup brush wheel brush Continue to polish the amalgam until the tin oxide begins to dry and a high luster is achieved. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Rinse and dry the tooth Examine with mouth mirror and explorer The amalgam surface MUST NOT be heated above 140'F by the polishing procedure. 62 Phillip’s Science of Dental Materials;11th ed
REMOVAL OF AMALGAM patient is draped with a plastic apron rubber dam is customized to fit the existing tooth/teeth Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion underneath the dam, activated charcoal or chlorella is placed, along with a cotton roll and gauze. A Safe Protocol for AmalgamRemoval Journal of Environmental and Public Health 63 Volume 2012, Article ID 517391
goggles for the eyes and hair cap are placed oxygen is supplied to the patient with a nasal mask and the mercury vapor ionizer is turned on The operators also protect themselves with a filtered mask, eye and hair protection, and face shields Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion A Safe Protocol for AmalgamRemoval Journal of Environmental and Public Health 64 Volume 2012, Article ID 517391
new dental bur is used in the handpiece to ensure easy removal high volume suction and a continual addition of water spray are supplied to the site where the amalgam is being extracted if possible, the amalgam restoration is sectioned and then scooped out to eliminate as much mercury vapor release as possible Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion A Safe Protocol for AmalgamRemoval Journal of Environmental and Public Health 65 Volume 2012, Article ID 517391
oxygen and protective coverings are taken away immediate inspection under the dental dam gauze, cotton roll and activated charcoal are wiped away Gauze is then used to inspect the floor of the mouth and tongue to make sure no particulates seeped under the dam once all mucosal tissues are fully inspected and cleaned, the mouth is flushed with copious amounts of water, again to ensure no ingestion or absorption of amalgam particulates Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion A Safe Protocol for AmalgamRemoval;Jou rnal of Environmental and Public Health Volume 2012, Article 66 ID 517391
Recent advances in amalgam Gallium based alloys consolidated silver alloy system Indium containing alloy powder & binary Hg-Indium liquid alloy Fluoride containing amalgam Low mercury amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Bonded amalgam Essentials of operative dentistry; 67 I Anand Sherwood
Gallium based alloys HISTORY Metallic element Gallium was 1st predicted by Mendeleef in 1871, was 1st isolated by ‘de Boisbandran’ in 1875. 1920s, Gallium (Ga) was one of the substitutes suggested for Hg (Putt Kammer, 1928) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 1950s work by Smith and Associates (Smith and Caul 1956) showed the potential use of Ga system.
This direct filling material contains no mercury Gallium is liquid at room temperature Its use is based on remarkable ability of liquid gallium to wet surfaces of many solid Melting temperature of Ga can be suppressed below room temperature with addition of 44 appropriate amounts of In and Sn. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Commercial brands are available; Galloy, Bayswater, Gallium Gf and Gallium GF II. J Conserv Dent. 2010 Oct;13(4):204-8. Dental amalgam: An update
Composition Alloy: Ag- 50% Sn- 25% Cu- 13% Pd- 20% Liquid: Ga – 62% Ir – 25% Sn – 25% Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion BDJ;VOL.183;NO.1;JULY,1997
gAmalgamation CuGa2 and PdGa5 surrounding the unreacted alloy particles which are held together by matrix of Ag9In4 Properties – 1 hr. Comp. Strength 1 day Comp strength Tensile strength Creep Dimensional change - 343 MPa - 533 MPa. - 57 MPa - 0.17% 16 µm/cm Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion
ADVANTAGES  Rapid solidification.  Good marginal seal by expanding on solidification.  Heat resistant.  Compressive & tensile strength increases with time comparable with silver amalgam  Creep value are as low as 0.09% Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion  Sets early so polishing can be carried out the same day 72 BDJ;VOL.183;NO.1;JULY,1997
DISADVANTAGES low resistance to corrosion moisture contamination leads to dramatic expansion Dent Mat June' 98 14(3); 173-8. Mix is mushy & sticks to everything except tooth Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion high cost 73 BDJ;VOL.183;NO.1;JULY,1997
Mean hardness, the compressive strength, 24h tensile Strength and 24h flexural strength of Pd free Ga-alloy, were significantly lower than Tytin. Dent Mat Mar 2001 17 (2), 142-8. Galloy & Gallium GF II showed excessive expansion when contaminated and/or placed in fluids containing salts Quint Int, Mar'99, 30(3) 185-91. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Ga-alloy were consistently rougher than Hg based amalgam after polishing.. Dent, Mar-Apr’ 99 24(2) 103-8. 74
Galloy is more corrosionprone than high Cu Amalgam (Permite). Primary corrosion product of Galloy were -Ga2O3 and SnO2 Oper. Dent Sept – Oct’97;Vol 22, No. 209 - 16 The significant reduction in the 1 hr mean compressive fracture strength and hardness identified for Galloy® compared with Tytin® indicate a slower setting reaction in the gallium-based alloy. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Dental Materials Volume 17, Issue 2, March 2001, Pages 142-148 75
Consolidated silver alloy system • developed at the National Institute of Standards and Technology • Silver particles are suspended in a dilute fluoroboric acid solution to keep the alloy surfaces clean Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • The alloy, in a spherical form, is condensed into a prepared cavity in a manner similar to that for placing compacted gold J Conserv Dent. 2010 Oct;13(4):204-8. 76 Dental amalgam: An update
• One problem associated with the insertion of this material is that the alloy strain hardens, so it is difficult to compact it adequately to eliminate internal voids and to achieve good adaptation to the cavity without using excessive force Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 77 Dental amalgam: An update
Indium containing alloy powder & Binary mercury-Indium liquid alloy • Powell et al 1989, added pure indium powder into disperse phase high Cu alloy & triturated with mercury • They found significant decrease in mercury evaporation from amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • This was marketed as ‘Indisperse’ & ‘Indiloy’ Essentials of operative dentistry; 78 I Anand Sherwood
Youdelis also found that less mercury is required for mixing amalgam when it contains indium in concentrations up to 10%. Youdelis WV. J Canad Dent Assoc 1979 Indium-containing admixed high-copper amalgam exhibited a reduction in creep and an increase in strength. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Johnson GH, J Dent Res 1985 79
A five-year clinical study found that there was no significant difference in surface luster or texture between indium-containing alloys (5% and 10%) and Dispersalloy. Johnson GH, Bales DJ, Powell LV. Am J Dent 1992 Amalgam prepared with indium rapidly forms indium oxide and tin oxide films which reduce mercury release. Nakajima H, Awaiwa Y, Hashimoto H, Ferracane JL, Okabe T. J Dent Res 1997 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Biological tests of indium-containing amalgam show that it is no more cytotoxic or hemolytic than standard ADA Certified amalgam. Townsend JD, Hamilton AI, Sbordone L. J Dent Res 1983 80
Fluoride containing amalgam Addition of fluorides to conventional amalgam was proposed by Innes and Youdelis 1966, Serman 1970, Stone1971 Mechanism of Fluoride release dilution of salt crystals that are in contact with cavity wall by corrosion that liberates fluoride contained in mass of amalgam, e.g. Fluoralloy “slow release device” Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 81 Dental amalgam: An update
A conventional (Minimax), two single-particle high-Cu (Summalloy and Aristaloy CR), and two dispersed-phase (Cluster and Phasealloy) amalgam alloys were each admixed with 0.5 wt% of CuF2, InF3, SnF2, and CaF2, and evaluated for F−, Cu, and Sn release A ranking for F− release was Cluster (highest) Summalloy Minimax Phasealloy Aristaloy CR The effectiveness of the F− compounds in releasing F− CuF2 (highest) SnF2 InF3 (1.0%) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion CaF2 82 DM, Volume 6, Issue 4, October 1990, Pages 256-265
Low mercury amalgam • If alloy particles are closely packed together, mercury content in restoration can be reduced by 15-25% Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Essentials of operative dentistry; 83 I Anand Sherwood
Bonded amalgam • ‘Baldwin technique’ here amalgam was condensed onto upset ZnPO4 cement • Other cements like Glass Ionomer Cements (GIC), Zn polycarboxylate have been used Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • Recently, 4META has bee used for bonding amalgam to cavity walls J Conserv Dent. 2010 Oct;13(4):204-8. 84 Dental amalgam: An update
Amalgam bond is based on a dentinal bonding system developed in Japan by Nakabayashi and co-workers The bond strengths recorded in studies have varied, approximately 12–15 MPa, and seem to be routinely achievable Bond strengths achieved with admixed alloys tend to be slightly lower than those with spherical alloy Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Teeth with bonded amalgams were less sensitive than teeth with pin-retained amalgams J Conserv Dent. 2010 Oct;13(4):204-8. 85 Dental amalgam: An update
Bonding amalgams, compared to placing them conventionally, afforded no significant benefit upon restoration longevity Br Dent J. 2009 Jan 24;206(2):E3 Bonded amalgam restorations prevent over-preparation and reduce the tooth flexure GIC under amalgam provides chemical bonding in between amalgam and tooth structure and thus reduces the microleakage Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Indian J Dent Res. 2011 Mar-Apr;22(2):252-5 86
Amalgam bonding technique Self-etching primer is rubbed vigorously into the tooth surface, with plenty of the liquid present. Left in place for 30 seconds excess primer is either removed with a cottonwool pledget or blown away. The cavity is thoroughly dried thin film of the adhesive resin-cement is smeared over the cavity surface Amalgam is packed rapidly into the unset resin and then carved to the correct contour. 87 Picard’s manual of operative dentistry; 8th ed
The resin-cement shown is an ‘anaerobic adhesive’. This means that it polymerizes when air is excluded. A gel containing a reducing agent is therefore syringed around the margins to cause complete polymerization of the resin-cement. This gel is washed off within a few minutes final restoration 88 Picard’s manual of operative dentistry; 8th ed
Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 89
ALLERGY • Allergic responses represent an antigen-antibody reaction marked by itching, rashes, sneezing, difficulty in breathing, swelling , or other symptoms Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • Contact dermatitis or Coombs’ type IV hypersensitivity reactions represent the most likely physiologic side effect to dental amalgam 90 CRAIG’s Restorative Dental Materials;12th ed
• Usually small %age of people are allergic to mercury, when such a reaction has been documented by dermatologist or allergist, an alternative material (e.g. Composite or ceramic) must be used unless the reaction is self limiting (usually within 2 wks) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 91 CRAIG’s Restorative Dental Materials;12th ed
Immediate hypersensitivity reaction associated with the mercury component of amalgam restorations- a case report* • The release of mercury induced an acute reaction which resulted in erythematous lesions, severe burning and itchy sensation and difficulty in breathing • Skin patch test results indicated a very strong positive reaction to mercury • Amalgam restorations were replaced with composite filling material Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion * Br Dent J. 2008 Nov 22;205(10):547-550 92
Three Types of Mercury: 1. Elemental Hg - Is Used in Dental Amalgam • Heavy, odorless, silver-colored liquid • Inhalation is the main source of toxicity (Mercury poisoning can also occur from dermal exposure) • Hg well absorbed by lungs. • Need long-term exposure or one large exposure Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 93 CRAIG’s Restorative Dental Materials;12th ed
2. Inorganic Hg • Known as mercuric salts…i.e. mercuric chloride, mercuric iodide, cinnabar • Found in many folk medicine Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • Corrosive and can damage the kidneys • Long-term exposure can cause skin irritation, staining, and nerve damage 94 CRAIG’s Restorative Dental Materials;12th ed
3. Organic Mercury = Methylmercury • More potent and more bioaccumulative than other forms of mercury • Form to which humans are primarily exposed Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • The EPA is most concerned about methylmercury in the environment 95 CRAIG’s Restorative Dental Materials;12th ed
Estimated daily intake of mercury ( as given in Craig’s restorative dental materials, 12th ed) Source µg Hg vapor µg inorganic Hg µg Methyl Hg Atmosphere 0.12 0.038 0.034 Drinking water Food, fish Food, non fish - 0.05 - 0.94 - 20.00 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3.76 96 CRAIG’s Restorative Dental Materials;12th ed
Sources of mercury • Exposure to mercury can occur from many different sources, including diet, water, air & occupational exposure • WHO has estimated that eating seafood once a week raises urine Hg levels to 5-20 µg/L, 2-8 times the level of exposure from amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 1 µg/L=1mg/m³=1 part per billion(ppb) 97 CRAIG’s Restorative Dental Materials;12th ed
• Mercury blood levels that were measured in one study indicated that the average level in patients with amalgam was 0.7ng/ml compared with a value of 0.3ng/ml for subjects with no amalgam. This difference was found to be statistically significant (P=0.01) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • However, a study in Sweden demonstrated that one saltwater seafood meal per week raised avg blood levels of mercury from 2.3 to 5.1 ng/ml , a seven fold increase compared with that associated with amalgam restorations(0.4 ng/ml) 98 PHILLIPS’ Science of Dental Materials;11th ed
The normal daily intake of mercury is:15µg from food, 1µg from air, 0.4µg from water • On the basis of epidemiological studies, blood & serum mercury levels correlate with occupational exposures & diet, whereas urine mercury levels relates to amalgam burden Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion The actual body burden at any time is a function of the dosage & time of exposure 99 PHILLIPS’ Science of Dental Materials;11th ed
THRESHOLD LIMIT VALUE(TLV): Allowable exposure level to mercury vapor, 8hrs/day, 40hrs/wk OSHA RECOMMENDED TLV=0.05 mg/m³ Normal Mercury Level in Urine=0-0.02mg/lt Allowable max. limit in urine=0.15mg/lt Allowable max. limit in blood=3µg/lt Saliva & Urine normal levels are equal Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Most dental office mercury vapor levels lie below 0.05 mg/m³ The mercury enigma in dentistry; JADA,VOL.92,June 1976 100 PHILLIPS’ Science of Dental Materials;11th ed
TOLERABLE MERCURY CONCENTRATION IN URINE &BLOOD Br Dent J 1997;182;413-417 Mercury vapor at a conc. of 25 µg/m³ in air results in avg. conc. of 75 µg/lt (urine) & 10 ng/ml (blood) The lowest air threshold for the general public of 1 µg/m³ results in conc. of: 15 µg/lt in urine Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 4ng/ml in blood 101
• In one study, patients with amalgam restorations were monitored with mercury vapor detectors over a 24 hr period & the amount of vapor inhaled was calculated to be 1.7 µg/day • 3 other studies have confirmed that the magnitude of vapor exposure for a patient with 8-10 amalgam restorations is in the range of 1.1-4.4µg/day Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 102 PHILLIPS’ Science of Dental Materials;11th ed
TOXIC REACTIONS 3 -7µg/kg body weight 500µg/kg body weight LOWEST DOSE TO ELLICIT TOXIC REACTIONS Paresthesia 1000µg/kg body weight Ataxia 2000µg/kg body weight Joint pain 4000µg/kg body weight Hearing loss Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion DEATH 103 CRAIG’s Restorative Dental Materials;12th ed
Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Mercury level expressed as µg of Hg/gm of creatinine Sturdevant’s Art & Science of Operative Dentistry; 5th ed
Mercury poisoning Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Mercury toxicity in the dental office: a neglected problem 105 JADA,Vol.92,June 1976
Minamata disease • Came into existance after the Minimata Bay incident in Japan in 1952 • A local chemical plant (Chisso Corporation) disposed of its methylmercury waste into the nearby bay, contaminating the shellfish & causing toxic levels of mercury in the fish eaten by the local population • Symptoms were:1.Ataxic gait 2.Convulsions 3.Numbness in mouth & limbs 4.Constriction in the visual field 5.Difficulty in speaking Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 106 Sturdevant’s Art & Science of Operative Dentistry; 5th ed
Industrial waste into the bay Methymercury consumed by the fishes in the bay Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Child suffering from minamata disease after eating the contaminated fishes 107
In dental office, the source of mercury exposures related to amalgam include: Amalgam raw materials being stored for use ( usually as precapsulated packages) Mixed but unhardened amalgam during trituration, insertion, & intraoral hardening Amalgam scrap that has insufficient alloy to consume the mercury present completely Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Amalgam undergoing finishing & polishing operations Amalgam restorations being removed 108 Sturdevant’s Art & Science of Operative Dentistry; 5th ed
Amount of mercury released during manipulation of amalgam Br Dent J 1997;182;293-297 • Trituration=1-2µg • Condensation=6-8µg • Dry polishing=44µg • Wet polishing=2-4µg • Removal of amalgam restoration underwater spray & high volume suction=15-20µg • Additional evacuation for 1 min to remove residual amalgam dust=1.5-2µg Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 109
Risks to dentists & office personnel Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 110
Store mercury in unbreakable, tightly sealed containers Clean up any spilled mercury immediately Droplets may be picked up with narrow bore tubing connected ( via a wash bottle trap) to the low volume aspirator of the dental unit Storage locations should be near an exhaust vent that carries air out of the building Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 111 Sturdevant’s Art & Science of Operative Dentistry; 5th ed
Use tightly closed capsules during amalgamation Reusable capsule with a mechanical amalgamator should have a tightly fitting cap to avoid mercury leakage Salvage all amalgam scrap & store it under water that contains sodium thiosulfate (photographic fixer is convinient) ,water, glycerine Use conventional dental amalgam condensing procedures, manual & mechanical, but do not use ultrasonic amalgam condensers Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 112 CRAIG’s Restorative Dental Materials;12th ed
Work in well ventilated spaces Avoid carpeting dental operatories; decontamination of carpeting is very difficult If mercury comes in contact with skin, the skin should be washed with soap & water immediately Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 113 CRAIG’s Restorative Dental Materials;12th ed
Amalgam scrap & materials contaminated with mercury or amalgam should not be incinerated or subjected to heat sterilization Adequate water spray & suction should be used during amalgam polishing & removal During the intra oral placement & condensation procedures, rubber dam & high volume evacuation should be used Eye protection , a disposable mask & gloves are now standard requirements for dental offices Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 114 CRAIG’s Restorative Dental Materials;12th ed
Spent capsules & mercury contaminated cotton rolls or paper napkins should not be thrown out with regular trash, rather they should be stored in a tightly capped plastic container or closed plastic bag for separate disposal Perform yearly mercury determinations on all personnel regularly employed in dental offices Determine mercury vapors levels in operatories periodically Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Alert all personnel who handle mercury, especially during training of the potential hazard of mercury vapors & the necessity for observing good mercury & amalgam practices 115 Sturdevant’s Art & Science of Operative Dentistry; 5th ed
AMALGAM WASTE MANAGEMENT 116
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The older generation of low-copper amalgams (before 1963) had a limited life span because they contained the gamma-2 phase that caused progressive weakening of the amalgam through corrosion Several clinical studies have demonstrated that high-copper amalgams can provide satisfactory performance for more than 12 years Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 120 Dental amalgam: An update
This appears to be true even for large restorations that replace cusps In addition, high-copper amalgams do not appear to require polishing after placement, as was recommended for low-copper amalgams, to increase their longevity Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 121 Dental amalgam: An update
Plasmins et al. evaluated the long-term survival of multisurface restorations and found that extensive amalgam restoration had no influence on the survival rate J Dent Res. 1998;77:453–60 this is in accordance with the results of a retrospective study by Robins and Summitt, who found 50% survival rate for 11.5 years Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Oper Dent. 1988;13:54–7 122
The satisfactory functioning of the extensive amalgam restorations over a long period of time results from the prevention of the most important traditional mechanical failure of amalgam restorations. These include marginal fracture, bulk fracture and tooth fracture. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 123 Dental amalgam: An update
The zinc and copper content of the alloy has been found to have a strong impact on the survival rates of amalgam restorations since it influences the corrosion resistance of the amalgam. High-copper amalgams has higher survival rates than conventional amalgams Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 124 Dental amalgam: An update
` • Letzel investigated survival and modes of failure of amalgam restorations retrospectively. The leading mode of failure was bulk fracture (4.6%), followed by tooth fracture (1.9%) and marginal ridge fracture (1.3%). For other reasons, 0.8% Amalgam restorations: Survival, failures and causes of failure of Mater. restorations failed Dent the 1989;5:115–21 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 125
ALTERNATIVES TO AMALGAM Metal alloys:Cast gold Gallium alloys TOOTH COLORED ALTERNATIVES Glass ionomer cements Composite resins Glass ionomer resin hybrids Compomers Ceramics Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Br Dent J 1997; 183: 11-14126
Dr G V Black Dr Michael Buonocore 127
COMPOSITES….. • Aesthetically superior • Mercury-free • Strengthens the tooth by chemical bonding thereby reducing the chance of tooth fracture Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 128
Safety of Composite resin Br Dent J 1997; 183: 11-14 • Produce more cytotoxicity than amalgam in comparative in vitro tests • Classifiable as toxic restorative material Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • Produce an inflammatory response in pulp when placed in test cavities in animals • Strongly allergenic • Inhibit RNA synthesis of cells 129
 Prospective clinical studies have shown comparable annual failure rates of both materials (Manhart et a!., 2004). • However, three recently published studies reported better longevity of amalgam restorations compared with composite restorations (Van Nieuwenhuysen et at, 2003; Berrtardo et at, 2007; Soncini at at, 2007). Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 130
amalgam has a greater longevity than composite resin in posterior restorations Longevity of Composite Resin and Amalgam Restorations in Posterior Teeth: An Evidence-Based Review of the Literature DEN300Y – Community Dentistry, winter 2009 Numerous studies have shown amalgam restoration to last longer than resin composite restorations Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Amalgam-Resurrection & Redemption Quintessence Int 2001;32;525-535 131
12-year Survival of Composite vs. Amalgam Restorations NJ.M. Qpdam*, E.M. Bronkhorst, B.A.C. Loomans, and M.-C.D.NJ.M. Huysmans JDentRes 89(10):1063-l067, 2010 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 132
Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Survey of Practice Types Civilian General Dentists 32% Amalgam free Amalgam users 68% 133 Gen Dent 2005 Sep-Oct;53(5):369-75
Frequency of Posterior Materials by Practice Type Amalgam Users 3% 7% 39% 51% Amalgam Amalgam Free Direct Composite 12% Indirect Composite Other Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3% 8% 77% 134 Gen Dent 2005 Sep-Oct;53(5):369-75
Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Do you place fewer amalgams Manipulation than 5 years ago? Recent advances Sideeffects of 12% mercury No Durability Future Conclusion Yes Profile of Amalgam Users Civilian Practitioners Do you use amalgam in your practice? 22% No Yes 78% 88% 135 DPR 2005
Review of Clinical Studies (Failure Rates in Posterior Permanent Teeth) % Annual Failure 8 6 4 2 0 Amalgam Direct Comp Comp Inlays Longitudinal Ceramic CAD/CAM Inlays Inlays Gold Inlays & Onlays Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion GI Cross-Sectional 136 J Adhes Dentistry 2001 Spring;3(1):45-64.
Review of Clinical Studies (Failure Rates in Posterior Permanent Teeth) % Annual Failure 15 10 Standard Deviation Longitudinal and Cross-Sectional Data 5 AR T Tu nn el GI Am al ga Di m re ct Co Co mp m po m Co er m p Ce In la ra ys m ic In la CA ys D/ CA M Ca st G ol d 0 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 137 Oper Dent2004 Sep-Oct;29(5):481-508
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Future of dental amalgam • The prediction that amalgam would not last until the end of the 20th century was wrong. Its unaesthetic appearance, its inability to bond tooth, concerns about the mercury and versatility of other materials have not led to the elimination of this inexpensive and durable material. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 139 Dental amalgam: An update
Mercury released from dental amalgam restorations does not contribute to systemic disease or systemic toxicological effects Allergic reactions to mercury from dental amalgam restorations have been demonstrated, but these are extremely rare Available scientific data do not justify the discontinuation of dental amalgam use from clinical practice or the replacement with other single-tooth restorative dental materials. There are cases where dental amalgam is the only choice with no other alternative Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Biocompatibility of Dental Amalgams-a review International Journal of Dentistry;Volume 2011, Article ID 981595,140 7 pages doi:10.1155/2011/981595
possibility & perhaps probability that dental amalgam will lose its importance in some more distant future the importance of dental amalgam at present and at least in the near future, the fact that dental amalgam is a material unique to the dental application CRITICAL ISSUES FOR Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion AMALGAM’S FUTURE DENTAL AMALGAM: REACTOR RESPONSE 141 Adv Dent Res 2(l):87-90, August, 1988
the longevity of dental restorations is dependent on many factors, including those related to materials, the dentist, and the patient Amalgam restorations are being replaced because of alleged adverse health effects and inferior aesthetic appearance Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Is it the end of the road for dental amalgam? A critical review Shenoy A; Conserv Dent. 2008 Jul;11(3):99-107 142
TEN CLINICAL & LEGAL MYTHS OF ANTIAMALGAM Amalgam-Resurrection & Redemption –I Quintessence Int,2001;32:525-535 FACT 1. Teeth with amalgam restorations have acusps MYTH 1. Amalgams commonly cause fractured low incidence of fractured cusps MYTH 2. the majority of clinically sound amalgam FACT 2. the vast majority of teeth with amalgam restorations have recurrent caries; the majority of restorations do not have recurrent caries resin restorations do not Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion FACT 3. numerous studies restorations last as long as MYTH 3. Resin composite have shown that amalgam restorations longer than resin composite restorations amalgam restorations 143
FACT 4. amalgam can be bonded to teeth; often MYTH 4. amalgam cannot be bonded to teeth yielding bond strength higher than obtained by resin composite FACT 5.5. because of recent advances in materials & MYTH improvements in amalgam restorative material & technique,in recent years have been as dramatic as techniques most studies of resin composites are those in resin compositeof amalgam are not outdated ;most studies materials FACT 6.6. resin composite restorations are superiorcan MYTH like resin composite restorations amalgam to often be repaired composites can be repaired amalgam because Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion MYTH Amalgam’s is 100 yrs old; resin composite is FACT 7.7. amalgamlongevity is testament to its safety & much newer & thus better efficacy Amalgam-Resurrection & Redemption –I Quintessence Int,2001;32:525-535
MYTH 8. The ADA refuseson the safety & efficacy of FACT 8. ADA’s statements to admit that mercury containing amalgam apparently unrelated to fear of dental amalgam are is unsafe for fear of lawsuits lawsuits MYTH neither the holds the patent for amalgam & FACT 9.9. The ADA ADA nor the ADA’S health receives a have ever each amalgam restoration foundationroyalty for received remuneration for any placed amalgam restoration ever placed Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion FACT 10. Dental amalgam has not been banned in any MYTH 10. Amalgam has been banned in Germany & country in the European union Sweden Amalgam-Resurrection & Redemption –I 145 Quintessence Int,2001;32:525-535
DISCUSSION “OPERATIVE DENTISTRY In on the threshold of postamalgam age , which is based on tooth colored restorative material” Krejci & Lutz;1995 Operative dentistry;1995,20,218-22 We should seek alternatives, if such alternatives can meet the health needs of our patients equally well or better Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Rory Hume; Quintessence Int,1996;27:2 146
If composite resins ,which can be costly ,pose the next biological risk in dentistry , what materials do we move to next?? Steven Duke; Compendium; Feb2003;vol24, no22 The future of dental amalgam is dependent on emotional & socioeconomic aspects that are different in each nation Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Roulet, Zimmer, Losche & Noack; Quintessence Int,1996;27:2 147
As other materials and techniques improve, the use of amalgam will likely continue to diminish, and it will eventually disappear from the scene Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Yet, amalgam continues to be the best bargain in the restorative armamentarium because of its durability and technique insensitivity J Conserv Dent. 2010 Oct;13(4):204-8. 148 Dental amalgam: An update
“Amalgam will probably disappear eventually, but its disappearance will be brought about by a better and more esthetic material, rather than by concerns over health hazards” “ When it does disappear, it will have served dentistry and patients well for more than 200 years” Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. Dental amalgam: An update 149
CONCLUSION 150
CONCLUSION • Amalgam restorations have served the profession well and will continue to do so in the years to come. In terms of longevity, they are probably superior to composite resins, especially when used for large restorations and cusp capping Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 151 Dental amalgam: An update
The new high copper single composition alloys offer superior properties but may not offer as good seal as older amalgams The use of amalgam can be continued as a material of choice if esthetics is not a concern. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Prepare a tooth as conservative as possible, making access large enough only for removal of carious dentin and using resin sealants for non carious fissures J Conserv Dent. 2010 Oct;13(4):204-8. 152 Dental amalgam: An update
Dental Amalgam will not go away even if it were to be immediately discontinued as a restorative material. It will keep going , going & going 153
REFERENCES • PHILLIPS’ Science of Dental Materials;11th ed Kenneth J. Anusavice • CRAIG’s Restorative Dental Materials;12th ed John M. Powers, Ronald L. Sakaguchi • Materials science for dentistry;9th ed B.W.Darvell • Sturdevant’s Art & Science of Operative Dentistry; 5th ed; Roberson, Heymann, Swift • fundamentals of operative dentistry, a contemporary approach; 3rd ed Summitt, Robbins, Hilton, Schwartz • Essentials of operative dentistry; I Anand Sherwood 154
• Dental amalgam: An update J Conserv Dent. 2010 Oct-Dec; 13(4): 204–208 • Effect of admixed indium on the clinical success of amalgam restorations . • • operative dentistry journal1992 Sep-Oct;17(5):196-202 JPD 1981;VOL46;.5 Dental Materials, Volume 3, Issue 3, June 1987, Pages 117-120 • A Safe Protocol for AmalgamRemoval • • • • • Journal of Environmental and Public Health;Volume 2012 BDJ;VOL.183;NO.1;JULY,1997 Dent Mat Mar 2001 17 (2), 142-8 Quint Int, Mar'99, 30(3) 185-91 DM, Volume 6, Issue 4, October 1990, Pages 256-265 Br Dent J. 2009 Jan 24;206(2):E3 • Immediate hypersensitivity reaction associated with the mercury component of amalgam restorations • • Br Dent J. 2008 Nov 22;205(10):547-50 The mercury enigma in dentistry; JADA,VOL.92,June 1976 Mercury toxicity in the dental office: a neglected problem JADA,Vol.92,June 1976 155
• Br Dent J 1997;182;293-297 • J Dent Res. 1998;77:453–60 • Oper Dent. 1988;13:54–7 • Amalgam restorations: Survival, failures and causes of failure Dent Mater. 1989;5:115–21 • Br Dent J 1997; 183: 11-14 • Longevity of Composite Resin and Amalgam Restorations in Posterior Teeth: An Evidence-Based Review of the Literature DEN300Y – Community Dentistry, winter 2009 • Amalgam-Resurrection & Redemption Quintessence Int 2001;32;525-535 • 12-year Survival of Composite vs. Amalgam Restorations JDentRes 89(10):1063-l067, 2010 • Review of the clinical survival of direct and indirect restorations in posterior teeth of the permanent dentition Oper. Dent. 2004 Sep-Oct;29(5):481-508 • Survey of general dentists regarding posterior restorations, selection criteria, and associated clinical problems. Gen Dent 2005 Sep-Oct;53(5):369-75; quiz 376, 367-8. 156
• • Longevity of restorations in posterior teeth and reasons for failure J Adhes Dentistry 2001 Spring;3(1):45-64. Review of the clinical survival of direct and indirect restorations in posterior teeth of the permanent dentition Oper Dent2004 Sep-Oct;29(5):481-508 Biocompatibility of Dental Amalgams-a review International Journal of Dentistry Volume 2011, Article ID 981595, 7 pages • DENTAL AMALGAM: REACTOR RESPONSE Adv Dent Res 2(l):87-90, August, 1988 • Is it the end of the road for dental amalgam? A critical review Shenoy A; Conserv Dent. 2008 Jul;11(3):99-107 • Amalgam-Resurrection & Redemption –I Quintessence Int,2001;32:525-535 • • • Operative dentistry;1995,20,218-22 Quintessence Int,1996;27:2 Steven Duke; Compendium; Feb2003;vol24, no22 157
158

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Amalgam past,present & future-2

  • 1.
    POSTGRADUATE DEPARTMENT OFCONSERVATIVE DENTISTRY AND ENDODONTICS SEMINAR TOPIC:- DENTAL AMALGAMPAST,PRESENT & FUTURE-II (TECHNICAL CONSIDERATIONS, PRESENT SCENARIO & FUTURE) Presented by- Ashish Choudhary Pg student UNDER GUIDANCE OF :- Prof. Dr Riyaz Farooq (HOD) Dr Aamir Rashid (lecturer) Dr Fayaz Ahmed (lecturer) 1
  • 2.
    Contents  Introduction  Historyof amalgam  Amalgam wars  Classification  Components of amalgam  Basic setting reaction  Manufacture of alloy powder  Properties of amalgam  Manipulation of amalgam  Recent advances in amalgam  Side effects of mercury  Durability of amalgam  Future of amalgam  Conclusion 2
  • 3.
  • 4.
  • 5.
    Selection of alloy involves a number of factors, including setting time, particle size & shape & composition, particularly as it relates to the elimination of the γ2 phase & the presence or absence of zinc Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion More than 90% of the dental amalgams currently placed are high copper alloys including spherical & admixed types 5 Phillip’s Science of Dental Materials;11th ed
  • 6.
    Selection of alloymainly aims at High one hour strength Minimum dimensional change Lowest creep value Good condensing property High corrosion resistance Good polishing and finishing abilities Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 6
  • 7.
    Mercury /alloy ratio •Important variable 7
  • 8.
    Mercury/alloy ratio • Earlierexcess mercury was used to achieve smooth & plastic amalgam mix • This excess Hg was removed from the amalgam by:1. Squeezing the excess Hg out by using squeeze cloth before insertion of increments in the prepared cavity 2. Increasing dryness technique Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 8 Phillip’s Science of Dental Materials;11th ed
  • 9.
    Eames minimal mercurytechnique Recommended ratio→ 1:1→ 50% Hg Lathe cut alloys =50% Spherical alloys = 42% Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion produce a workable mass 9 Phillip’s Science of Dental Materials;11th ed
  • 10.
    • VARIOUS METHODS– PROPORTIONING PREWEIGHED TABLET : specific weight of powder with appropriate Hg is dispensed into mixing capsule • proportion– by wt – not by volume • %Hg can be adjusted from 48-55%. DISPENSERS : accommodate 2 containers • 1- having Hg; • 2 – powder. • specific volume of powder & Hg - dispensed Into capsule. • proportion– by volume – not by wt Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 10 Phillip’s Science of Dental Materials;11th ed
  • 11.
    • DISPOSABLE CAPSULES •SELF ACTIVATING CAPSULES • Reusable capsules • Preamalgamated alloys 11 Sturdevant’s Art & Science of Operative Dentistry;5th ed
  • 12.
    SIZE OF MIX Capsulescontaining 400, 600 or 800mg of alloy and the appropriate Hg are available Colour coded for easy identification of capsules. • • • • 400mg - single mix. 600mg – single mix. 800mg – double mix 1200mg – for amalgam core Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 14 CRAIG’s Restorative Dental Materials;12th ed
  • 13.
  • 14.
    TRITURATION • Defined asprocess of grinding powder, esp. within a liquid. In dentistry, the term is used to describe the process of mixing the amalgam alloy particles with mercury in an amalgamator (as given in Phillip’s , 11th edn) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 16 Phillip’s Science of Dental Materials;11th ed
  • 15.
    • Objective:-to wetall the surfaces of the alloy particles with Hg -for proper wetting, the alloy surface should be clean Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion -rubbing of the particles mechanically removes the oxide film coating on alloy particles 17 Phillip’s Science of Dental Materials;11th ed
  • 16.
    • Trituration isachieved either by : A) Hand mixing B) Mechanical mixing Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 18 Phillip’s Science of Dental Materials;11th ed
  • 17.
    v HAND TRITURATION MORTAR PESTLE Roughened inner surface,maintained by carborundum paste Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion glass rod with a round end 19 Phillip’s Science of Dental Materials;11th ed
  • 18.
    • The 3factors to obtain a well mixed amalgam mass are: 1. Number of rotations 2. Speed of rotation Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3. Magnitude of pressure placed on the pestle. Typically a 25-45 seconds period is sufficient 20 Phillip’s Science of Dental Materials;11th ed
  • 19.
    Mechanical trituration • Triturationof alloy & Hg is done with a mechanical mixing device called an “amalgamator or triturator” • The disposable capsule serves as a mortar Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • a cylindrical metal or plastic piston is placed in the capsule which serve as a pestle 21 Phillip’s Science of Dental Materials;11th ed
  • 20.
    AMALGAMATORS FOR MECHANICAL TRITURATION SPEED TIME Thespeed used is recommended by the manufacturer. High ENERGY = Speed higher copper alloys require x Time mixing speeds The capsule is inserted b/w the armscapsule oscillate at When amalgamatorsarms automaticthe on speed of the The put on, the have holding timer &3800,top - 40- 4400 low speed 32 -3400cycles/min, medium - 37high 22 machines device triturating the amalgam high speed, thus control
  • 21.
    • Using aparameter called coherence time (tc), defined as the minimum mixing time required for an amalgam to form a single coherent pellet, it has been found that the compressive strength, dimensional change & creep are optimized if mixing is carried out for a time of 5tc. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 23 Phillip’s Science of Dental Materials;11th ed
  • 22.
    MIXING TIME --spherical alloysusually require less amalgamation time than lathe cut alloys --a large mix requires slightly longer mixing time than a smaller one Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 24 Phillip’s Science of Dental Materials;11th ed
  • 23.
    • Advantages ofmechanical trituration: 1.Shorter mixing time 2.More standardized procedure Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3.Require less mercury when compared to hand mixing technique 25 Phillip’s Science of Dental Materials;11th ed
  • 24.
  • 25.
    Undertriturated mix        is rough& grainy may crumble mix hardens too rapidly excess mercury will remain gives a rough surface after carving tarnish & corrosion may occur less strength Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 27 Phillip’s Science of Dental Materials;11th ed
  • 26.
    NORMAL MIX  shinysurface smooth & soft consistency  warm, when removed from the capsule best compressive & tensile strength increased resistance to tarnish & corrosion Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 28 Phillip’s Science of Dental Materials;11th ed
  • 27.
    Overtriturated mix Soupy mix difficultto remove from the capsule too plastic to manipulate decreased working time higher contraction of amalgam strength of lathecut alloys is increased, whereas it is reduced in high copper alloys increased creep Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 29 Phillip’s Science of Dental Materials;11th ed
  • 28.
    MULLING • Continuation oftrituration • Hand mulling  Dry piece of rubber dam or glove  Rubbed between the first finger and thumb  2 to 5 seconds. • Mechanical mulling mix is retriturated in an pestle free capsule for an addtional 2-3 sec • Advantages Coherent, consistent and homogenous mix Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 30
  • 29.
  • 30.
    CONDENSATION • The amalgamis placed in the cavity after trituration & the packed (condensed) using suitable instruments • Goal of condensation-is to compact the alloy into the prepared cavity so that the greatest possible density is achieved, with sufficient Hg to ensure complete continuity of the matrix phase(Ag2Hg3) b/w the remaining alloy particles Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 32 Phillip’s Science of Dental Materials;11th ed
  • 31.
    Aims of condensation 1.to secure adaptation of the amalgam to the walls and the margins 2. to get compactness and homogeneity of the amalgam in the restoration with minimal voids Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3. Remove the excess mercury 33 Phillip’s Science of Dental Materials;11th ed
  • 32.
    Modes of condensation Manualcondensation Mechanical condensation Pneumatic Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Electrical 34
  • 33.
    Condensers  Are instrumentswith serrated tips of different shapes & sizes  The shapes are oval, crescent, trapezoidal, triangular, circular or square Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion  Condenser type is selected as per the area & shape of the cavity  Smaller the condenser, greater is the pressure exerted on the amalgam 35 Phillip’s Science of Dental Materials;11th ed
  • 34.
    Condensation technique • Thefield of operation should be kept absolutely dry during condensation The amalgam should be carried to the cavity with amalgam carrier incrementally Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Immediate condensation done after each increment with sufficient pressure (3-4 pounds) in vertical and horizontal direction starting with smaller condenser 36 Phillip’s Science of Dental Materials;11th ed
  • 35.
    • The condensationis started at the center & the condenser point is stepped little by little towards the cavity walls The procedure of adding an increment and condensing it, adding another increment is continued until the cavity is overfilled (about 1mm) and the filling is over packed with larger condenser Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Explorer tine to scrap the BLOTTING MIX marginal ridge 37 Phillip’s Science of Dental Materials;11th ed
  • 36.
    GENERAL GUIDELINES Modern amalgamsare fast setting & so working time is short A fresh mix of amalgam should be ready if condensation takes more than 3-4 minutes Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion After condensation of each increment –remove any excess Hg 15 lbs of pres. of condensation recommended Avg force used is 3-4 lbs (13.3 – 17.8 N) 38 Phillip’s Science of Dental Materials;11th ed
  • 37.
    LATHE CUT AMALGAM SPHERICALAMALGAM Small High force condensers ADMIXED AMALGAM Low Hg/alloy ratio Less condensation force req. Larger condensers Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion intermediate handling between More lateral and spherical lathe-cut condensation 39 Phillip’s Science of Dental Materials;11th ed
  • 38.
  • 39.
    Precarving burnishing • Formof condensation to ensure dense amalgam at the margins & aids in shaping of the restoration Heavy stroke with large burnisher moving from the center of the restoration outwards beyond the margins Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion As crystallization of amalgam occurs, it's consistency becomes much stiffer, it is suitable for carving 41 Phillip’s Science of Dental Materials;11th ed
  • 40.
  • 41.
    CARVING OF AMALGAM Initialcarving consist of removal of the bulk excess using a large spoon excavator OBJECTIVES: Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion no undercuts proper physiological contours minimal flash functional, non-interfering occlusal anatomy Adequate, compatible marginal ridges Proper size, location, extent & interrelationship of contact areas Preserving Biological width 43 Phillip’s Science of Dental Materials;11th ed
  • 42.
    The carving shouldnot be started untill amalgam is hard enough to be carved scrapping or ringing sound CARVING INSTRUMENTS: 1.Cleoid-Discoid Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 2.Spoon Excavator 3.Hollenback 4.Wards 5.Diamond shaped 44 Phillip’s Science of Dental Materials;11th ed
  • 43.
    CARVING TECHNIQUE Select anacorn burnisher that will be wide enough to ride the isthmus without entering the preparation After condensation induce heavy pressure through out the length of the central and developmental grooves Strokes – from tooth to amalgam surface, or laterally along tooth – amalgam interface Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion All accessible embrasures established in restoration- sharp explorer or lateral edges of hollenback carver 45 JPD 1981;VOL46;NO.5
  • 44.
    Create triangular fossae– discoid, cleiod carvers, diamond shaped carver Define marginal ridges – sharp explorer Carver moves parallel to the margin Carver should rest on enamel as well as amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Surface is rendered smooth and free of gross excess material by using a tightly twisted cotton 46 JPD 1981;VOL46;NO.5
  • 45.
    Guidelines for carving Pullingstrokes – mostly Pushing stroke - developing occlusal anatomy Occlusal anatomy should be kept reasonably (shallow) to preserve a bulk of amalgam at the margin 75 – 90 angle at the margin of occlusal amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Mesial and distal pit areas should be carved slightly deeper than the proximal marginal ridge Undercarving leads to amalgams grown out appearance 47
  • 46.
  • 47.
  • 48.
    Burnishing of amalgam •it is a light rubbing of the carved surface with the burnisher to improve smoothness & produce a shiny appearance & produce a denser amalgam with more compaction , adaptation and sealing of amalgam at the margins Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 50 Phillip’s Science of Dental Materials;11th ed
  • 49.
    Burnishing is donewith a ball burnisher using light stroke proceeding from the amalgam surface to the tooth surface Heavy forces should not be used Brings excess Hg to surface – discarded If the temperature rises above 60 ͦC, mercury is released which may cause corrosion & fracture at the margins Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Pre carving and post carving burnishing > only Pre or post carving burnishing Dental Materials, Volume 3, Issue 3, June 1987, Pages 117-120 51 Phillip’s Science of Dental Materials;11th ed
  • 50.
    light closer ismade and the surface checked for the heavier burnished areas, lateral slide is used to develop the desired eccentric occlusion Articulating paper may be used to check the occlusion Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Finally the grooves are enhanced with "conical amalgam burnisher" and the amalgam is smoothened by a small damp ball of cotton 52 Phillip’s Science of Dental Materials;11th ed
  • 51.
  • 52.
    Finishing & Polishing •is necessary to complete the carving, to refine the anatomy, contours, and marginal integrity and enhance the surface finishing of the restoration • they reduce the surface roughness of the restoration with less prone to tarnish and corrosion Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 54 Phillip’s Science of Dental Materials;11th ed
  • 53.
    AFTER INITIAL SETTING Prophycup with pumice provides initial smoothness to restorations Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 55 Phillip’s Science of Dental Materials;11th ed
  • 54.
    FINAL POLISHING Done onlyafter amalgam sets, delayed at least 24 hrs following condensation High Cu single composition spherical alloy: 8 min after trituration Always - low speed, low pressurevelvet finish AVOID UNDUE PRESSURE Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion USE ADEQUATE COOLING 56 CRAIG’s Restorative Dental Materials;12th ed
  • 55.
    FINISHING& POLISHING instruments foramalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Fig. From the left: five plain-cut plain steel finishing burs, two mounted stones, three mounted abrasive rubber points from coarse to fine, and a mounted abrasive rubber cup 57 Phillip’s Science of Dental Materials;11th ed
  • 56.
    Finishing Discs Technique Use short,overlapping strokes and move diagonally across the cavosurface margins. Sequence Discs are used in a sequence of more abrasive to less abrasive grits. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Embrasures When using discs in embrasure areas, care must be taken not to damage the contact area or papilla. Phillip’s Science of Dental Materials;11th ed
  • 57.
    Finishing strips a) Types: fine or medium b) Placed on both the tooth and the amalgam, and move in a back-and-forth motion. c) Avoid the contact area when using finishing strips, and use caution in areas of the inter dental papilla and surrounding tissue Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Wider strips may be cut in half lengthwise to make narrow strips 59 Phillip’s Science of Dental Materials;11th ed
  • 58.
    Finishing burs/stones 1. Greenstone to remove excess material and irregularities 2. Sequence largest bur →→ smaller and less abrasive burs 3. Technique Adapt the side of the bur or stone along the margin, contacting both tooth and amalgam. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 4. Direction of stroke Rotate the bur or stone from the amalgam to the tooth to avoid fracturing the amalgam margins. 5. Direction of work Always begin at the centre of the restoration and work toward the cavosurface margin 60 Phillip’s Science of Dental Materials;11th ed
  • 59.
    POLISHING POINTS &RUBBER CUPS Abrasive-impregnated rubber cups & points are brownies in 3 colors super greenies Brown Green Yellow-banded green greenie USE Cups Points • • • - proximal surfaces Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion USED Each color denotes different degree of INTERCHANGEABLY - abrasiveness occlusal surface. relatively low speed light, intermittent strokes wet conditions. 61 Phillip’s Science of Dental Materials;11th ed
  • 60.
    PUMICE is mixedwith TIN OXIDE slurries rubber cup brush wheel brush Continue to polish the amalgam until the tin oxide begins to dry and a high luster is achieved. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Rinse and dry the tooth Examine with mouth mirror and explorer The amalgam surface MUST NOT be heated above 140'F by the polishing procedure. 62 Phillip’s Science of Dental Materials;11th ed
  • 61.
    REMOVAL OF AMALGAM patientis draped with a plastic apron rubber dam is customized to fit the existing tooth/teeth Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion underneath the dam, activated charcoal or chlorella is placed, along with a cotton roll and gauze. A Safe Protocol for AmalgamRemoval Journal of Environmental and Public Health 63 Volume 2012, Article ID 517391
  • 62.
    goggles for theeyes and hair cap are placed oxygen is supplied to the patient with a nasal mask and the mercury vapor ionizer is turned on The operators also protect themselves with a filtered mask, eye and hair protection, and face shields Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion A Safe Protocol for AmalgamRemoval Journal of Environmental and Public Health 64 Volume 2012, Article ID 517391
  • 63.
    new dental buris used in the handpiece to ensure easy removal high volume suction and a continual addition of water spray are supplied to the site where the amalgam is being extracted if possible, the amalgam restoration is sectioned and then scooped out to eliminate as much mercury vapor release as possible Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion A Safe Protocol for AmalgamRemoval Journal of Environmental and Public Health 65 Volume 2012, Article ID 517391
  • 64.
    oxygen and protectivecoverings are taken away immediate inspection under the dental dam gauze, cotton roll and activated charcoal are wiped away Gauze is then used to inspect the floor of the mouth and tongue to make sure no particulates seeped under the dam once all mucosal tissues are fully inspected and cleaned, the mouth is flushed with copious amounts of water, again to ensure no ingestion or absorption of amalgam particulates Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion A Safe Protocol for AmalgamRemoval;Jou rnal of Environmental and Public Health Volume 2012, Article 66 ID 517391
  • 65.
    Recent advances inamalgam Gallium based alloys consolidated silver alloy system Indium containing alloy powder & binary Hg-Indium liquid alloy Fluoride containing amalgam Low mercury amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Bonded amalgam Essentials of operative dentistry; 67 I Anand Sherwood
  • 66.
    Gallium based alloys HISTORY Metallicelement Gallium was 1st predicted by Mendeleef in 1871, was 1st isolated by ‘de Boisbandran’ in 1875. 1920s, Gallium (Ga) was one of the substitutes suggested for Hg (Putt Kammer, 1928) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 1950s work by Smith and Associates (Smith and Caul 1956) showed the potential use of Ga system.
  • 67.
    This direct filling materialcontains no mercury Gallium is liquid at room temperature Its use is based on remarkable ability of liquid gallium to wet surfaces of many solid Melting temperature of Ga can be suppressed below room temperature with addition of 44 appropriate amounts of In and Sn. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Commercial brands are available; Galloy, Bayswater, Gallium Gf and Gallium GF II. J Conserv Dent. 2010 Oct;13(4):204-8. Dental amalgam: An update
  • 68.
    Composition Alloy: Ag- 50% Sn- 25% Cu-13% Pd- 20% Liquid: Ga – 62% Ir – 25% Sn – 25% Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion BDJ;VOL.183;NO.1;JULY,1997
  • 69.
    gAmalgamation CuGa2 and PdGa5surrounding the unreacted alloy particles which are held together by matrix of Ag9In4 Properties – 1 hr. Comp. Strength 1 day Comp strength Tensile strength Creep Dimensional change - 343 MPa - 533 MPa. - 57 MPa - 0.17% 16 µm/cm Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion
  • 70.
    ADVANTAGES  Rapid solidification. Good marginal seal by expanding on solidification.  Heat resistant.  Compressive & tensile strength increases with time comparable with silver amalgam  Creep value are as low as 0.09% Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion  Sets early so polishing can be carried out the same day 72 BDJ;VOL.183;NO.1;JULY,1997
  • 71.
    DISADVANTAGES low resistance tocorrosion moisture contamination leads to dramatic expansion Dent Mat June' 98 14(3); 173-8. Mix is mushy & sticks to everything except tooth Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion high cost 73 BDJ;VOL.183;NO.1;JULY,1997
  • 72.
    Mean hardness, thecompressive strength, 24h tensile Strength and 24h flexural strength of Pd free Ga-alloy, were significantly lower than Tytin. Dent Mat Mar 2001 17 (2), 142-8. Galloy & Gallium GF II showed excessive expansion when contaminated and/or placed in fluids containing salts Quint Int, Mar'99, 30(3) 185-91. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Ga-alloy were consistently rougher than Hg based amalgam after polishing.. Dent, Mar-Apr’ 99 24(2) 103-8. 74
  • 73.
    Galloy is morecorrosionprone than high Cu Amalgam (Permite). Primary corrosion product of Galloy were -Ga2O3 and SnO2 Oper. Dent Sept – Oct’97;Vol 22, No. 209 - 16 The significant reduction in the 1 hr mean compressive fracture strength and hardness identified for Galloy® compared with Tytin® indicate a slower setting reaction in the gallium-based alloy. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Dental Materials Volume 17, Issue 2, March 2001, Pages 142-148 75
  • 74.
    Consolidated silver alloy system •developed at the National Institute of Standards and Technology • Silver particles are suspended in a dilute fluoroboric acid solution to keep the alloy surfaces clean Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • The alloy, in a spherical form, is condensed into a prepared cavity in a manner similar to that for placing compacted gold J Conserv Dent. 2010 Oct;13(4):204-8. 76 Dental amalgam: An update
  • 75.
    • One problemassociated with the insertion of this material is that the alloy strain hardens, so it is difficult to compact it adequately to eliminate internal voids and to achieve good adaptation to the cavity without using excessive force Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 77 Dental amalgam: An update
  • 76.
    Indium containing alloypowder & Binary mercury-Indium liquid alloy • Powell et al 1989, added pure indium powder into disperse phase high Cu alloy & triturated with mercury • They found significant decrease in mercury evaporation from amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • This was marketed as ‘Indisperse’ & ‘Indiloy’ Essentials of operative dentistry; 78 I Anand Sherwood
  • 77.
    Youdelis also foundthat less mercury is required for mixing amalgam when it contains indium in concentrations up to 10%. Youdelis WV. J Canad Dent Assoc 1979 Indium-containing admixed high-copper amalgam exhibited a reduction in creep and an increase in strength. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Johnson GH, J Dent Res 1985 79
  • 78.
    A five-year clinicalstudy found that there was no significant difference in surface luster or texture between indium-containing alloys (5% and 10%) and Dispersalloy. Johnson GH, Bales DJ, Powell LV. Am J Dent 1992 Amalgam prepared with indium rapidly forms indium oxide and tin oxide films which reduce mercury release. Nakajima H, Awaiwa Y, Hashimoto H, Ferracane JL, Okabe T. J Dent Res 1997 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Biological tests of indium-containing amalgam show that it is no more cytotoxic or hemolytic than standard ADA Certified amalgam. Townsend JD, Hamilton AI, Sbordone L. J Dent Res 1983 80
  • 79.
    Fluoride containing amalgam Additionof fluorides to conventional amalgam was proposed by Innes and Youdelis 1966, Serman 1970, Stone1971 Mechanism of Fluoride release dilution of salt crystals that are in contact with cavity wall by corrosion that liberates fluoride contained in mass of amalgam, e.g. Fluoralloy “slow release device” Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 81 Dental amalgam: An update
  • 80.
    A conventional (Minimax),two single-particle high-Cu (Summalloy and Aristaloy CR), and two dispersed-phase (Cluster and Phasealloy) amalgam alloys were each admixed with 0.5 wt% of CuF2, InF3, SnF2, and CaF2, and evaluated for F−, Cu, and Sn release A ranking for F− release was Cluster (highest) Summalloy Minimax Phasealloy Aristaloy CR The effectiveness of the F− compounds in releasing F− CuF2 (highest) SnF2 InF3 (1.0%) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion CaF2 82 DM, Volume 6, Issue 4, October 1990, Pages 256-265
  • 81.
    Low mercury amalgam •If alloy particles are closely packed together, mercury content in restoration can be reduced by 15-25% Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Essentials of operative dentistry; 83 I Anand Sherwood
  • 82.
    Bonded amalgam • ‘Baldwintechnique’ here amalgam was condensed onto upset ZnPO4 cement • Other cements like Glass Ionomer Cements (GIC), Zn polycarboxylate have been used Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • Recently, 4META has bee used for bonding amalgam to cavity walls J Conserv Dent. 2010 Oct;13(4):204-8. 84 Dental amalgam: An update
  • 83.
    Amalgam bond isbased on a dentinal bonding system developed in Japan by Nakabayashi and co-workers The bond strengths recorded in studies have varied, approximately 12–15 MPa, and seem to be routinely achievable Bond strengths achieved with admixed alloys tend to be slightly lower than those with spherical alloy Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Teeth with bonded amalgams were less sensitive than teeth with pin-retained amalgams J Conserv Dent. 2010 Oct;13(4):204-8. 85 Dental amalgam: An update
  • 84.
    Bonding amalgams, comparedto placing them conventionally, afforded no significant benefit upon restoration longevity Br Dent J. 2009 Jan 24;206(2):E3 Bonded amalgam restorations prevent over-preparation and reduce the tooth flexure GIC under amalgam provides chemical bonding in between amalgam and tooth structure and thus reduces the microleakage Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Indian J Dent Res. 2011 Mar-Apr;22(2):252-5 86
  • 85.
    Amalgam bonding technique Self-etchingprimer is rubbed vigorously into the tooth surface, with plenty of the liquid present. Left in place for 30 seconds excess primer is either removed with a cottonwool pledget or blown away. The cavity is thoroughly dried thin film of the adhesive resin-cement is smeared over the cavity surface Amalgam is packed rapidly into the unset resin and then carved to the correct contour. 87 Picard’s manual of operative dentistry; 8th ed
  • 86.
    The resin-cement shownis an ‘anaerobic adhesive’. This means that it polymerizes when air is excluded. A gel containing a reducing agent is therefore syringed around the margins to cause complete polymerization of the resin-cement. This gel is washed off within a few minutes final restoration 88 Picard’s manual of operative dentistry; 8th ed
  • 87.
  • 88.
    ALLERGY • Allergic responsesrepresent an antigen-antibody reaction marked by itching, rashes, sneezing, difficulty in breathing, swelling , or other symptoms Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • Contact dermatitis or Coombs’ type IV hypersensitivity reactions represent the most likely physiologic side effect to dental amalgam 90 CRAIG’s Restorative Dental Materials;12th ed
  • 89.
    • Usually small%age of people are allergic to mercury, when such a reaction has been documented by dermatologist or allergist, an alternative material (e.g. Composite or ceramic) must be used unless the reaction is self limiting (usually within 2 wks) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 91 CRAIG’s Restorative Dental Materials;12th ed
  • 90.
    Immediate hypersensitivity reactionassociated with the mercury component of amalgam restorations- a case report* • The release of mercury induced an acute reaction which resulted in erythematous lesions, severe burning and itchy sensation and difficulty in breathing • Skin patch test results indicated a very strong positive reaction to mercury • Amalgam restorations were replaced with composite filling material Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion * Br Dent J. 2008 Nov 22;205(10):547-550 92
  • 91.
    Three Types ofMercury: 1. Elemental Hg - Is Used in Dental Amalgam • Heavy, odorless, silver-colored liquid • Inhalation is the main source of toxicity (Mercury poisoning can also occur from dermal exposure) • Hg well absorbed by lungs. • Need long-term exposure or one large exposure Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 93 CRAIG’s Restorative Dental Materials;12th ed
  • 92.
    2. Inorganic Hg •Known as mercuric salts…i.e. mercuric chloride, mercuric iodide, cinnabar • Found in many folk medicine Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • Corrosive and can damage the kidneys • Long-term exposure can cause skin irritation, staining, and nerve damage 94 CRAIG’s Restorative Dental Materials;12th ed
  • 93.
    3. Organic Mercury= Methylmercury • More potent and more bioaccumulative than other forms of mercury • Form to which humans are primarily exposed Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • The EPA is most concerned about methylmercury in the environment 95 CRAIG’s Restorative Dental Materials;12th ed
  • 94.
    Estimated daily intakeof mercury ( as given in Craig’s restorative dental materials, 12th ed) Source µg Hg vapor µg inorganic Hg µg Methyl Hg Atmosphere 0.12 0.038 0.034 Drinking water Food, fish Food, non fish - 0.05 - 0.94 - 20.00 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3.76 96 CRAIG’s Restorative Dental Materials;12th ed
  • 95.
    Sources of mercury •Exposure to mercury can occur from many different sources, including diet, water, air & occupational exposure • WHO has estimated that eating seafood once a week raises urine Hg levels to 5-20 µg/L, 2-8 times the level of exposure from amalgam Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 1 µg/L=1mg/m³=1 part per billion(ppb) 97 CRAIG’s Restorative Dental Materials;12th ed
  • 96.
    • Mercury bloodlevels that were measured in one study indicated that the average level in patients with amalgam was 0.7ng/ml compared with a value of 0.3ng/ml for subjects with no amalgam. This difference was found to be statistically significant (P=0.01) Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • However, a study in Sweden demonstrated that one saltwater seafood meal per week raised avg blood levels of mercury from 2.3 to 5.1 ng/ml , a seven fold increase compared with that associated with amalgam restorations(0.4 ng/ml) 98 PHILLIPS’ Science of Dental Materials;11th ed
  • 97.
    The normal dailyintake of mercury is:15µg from food, 1µg from air, 0.4µg from water • On the basis of epidemiological studies, blood & serum mercury levels correlate with occupational exposures & diet, whereas urine mercury levels relates to amalgam burden Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion The actual body burden at any time is a function of the dosage & time of exposure 99 PHILLIPS’ Science of Dental Materials;11th ed
  • 98.
    THRESHOLD LIMIT VALUE(TLV):Allowable exposure level to mercury vapor, 8hrs/day, 40hrs/wk OSHA RECOMMENDED TLV=0.05 mg/m³ Normal Mercury Level in Urine=0-0.02mg/lt Allowable max. limit in urine=0.15mg/lt Allowable max. limit in blood=3µg/lt Saliva & Urine normal levels are equal Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Most dental office mercury vapor levels lie below 0.05 mg/m³ The mercury enigma in dentistry; JADA,VOL.92,June 1976 100 PHILLIPS’ Science of Dental Materials;11th ed
  • 99.
    TOLERABLE MERCURY CONCENTRATION INURINE &BLOOD Br Dent J 1997;182;413-417 Mercury vapor at a conc. of 25 µg/m³ in air results in avg. conc. of 75 µg/lt (urine) & 10 ng/ml (blood) The lowest air threshold for the general public of 1 µg/m³ results in conc. of: 15 µg/lt in urine Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 4ng/ml in blood 101
  • 100.
    • In onestudy, patients with amalgam restorations were monitored with mercury vapor detectors over a 24 hr period & the amount of vapor inhaled was calculated to be 1.7 µg/day • 3 other studies have confirmed that the magnitude of vapor exposure for a patient with 8-10 amalgam restorations is in the range of 1.1-4.4µg/day Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 102 PHILLIPS’ Science of Dental Materials;11th ed
  • 101.
    TOXIC REACTIONS 3 -7µg/kgbody weight 500µg/kg body weight LOWEST DOSE TO ELLICIT TOXIC REACTIONS Paresthesia 1000µg/kg body weight Ataxia 2000µg/kg body weight Joint pain 4000µg/kg body weight Hearing loss Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion DEATH 103 CRAIG’s Restorative Dental Materials;12th ed
  • 102.
    Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recentadvances Sideeffects of mercury Durability Future Conclusion Mercury level expressed as µg of Hg/gm of creatinine Sturdevant’s Art & Science of Operative Dentistry; 5th ed
  • 103.
    Mercury poisoning Introduction History Amalgam wars Classification Components settingreaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Mercury toxicity in the dental office: a neglected problem 105 JADA,Vol.92,June 1976
  • 104.
    Minamata disease • Cameinto existance after the Minimata Bay incident in Japan in 1952 • A local chemical plant (Chisso Corporation) disposed of its methylmercury waste into the nearby bay, contaminating the shellfish & causing toxic levels of mercury in the fish eaten by the local population • Symptoms were:1.Ataxic gait 2.Convulsions 3.Numbness in mouth & limbs 4.Constriction in the visual field 5.Difficulty in speaking Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 106 Sturdevant’s Art & Science of Operative Dentistry; 5th ed
  • 105.
    Industrial waste into the bay Methymercury consumedby the fishes in the bay Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Child suffering from minamata disease after eating the contaminated fishes 107
  • 106.
    In dental office,the source of mercury exposures related to amalgam include: Amalgam raw materials being stored for use ( usually as precapsulated packages) Mixed but unhardened amalgam during trituration, insertion, & intraoral hardening Amalgam scrap that has insufficient alloy to consume the mercury present completely Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Amalgam undergoing finishing & polishing operations Amalgam restorations being removed 108 Sturdevant’s Art & Science of Operative Dentistry; 5th ed
  • 107.
    Amount of mercuryreleased during manipulation of amalgam Br Dent J 1997;182;293-297 • Trituration=1-2µg • Condensation=6-8µg • Dry polishing=44µg • Wet polishing=2-4µg • Removal of amalgam restoration underwater spray & high volume suction=15-20µg • Additional evacuation for 1 min to remove residual amalgam dust=1.5-2µg Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 109
  • 108.
    Risks to dentists& office personnel Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 110
  • 109.
    Store mercury in unbreakable,tightly sealed containers Clean up any spilled mercury immediately Droplets may be picked up with narrow bore tubing connected ( via a wash bottle trap) to the low volume aspirator of the dental unit Storage locations should be near an exhaust vent that carries air out of the building Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 111 Sturdevant’s Art & Science of Operative Dentistry; 5th ed
  • 110.
    Use tightly closedcapsules during amalgamation Reusable capsule with a mechanical amalgamator should have a tightly fitting cap to avoid mercury leakage Salvage all amalgam scrap & store it under water that contains sodium thiosulfate (photographic fixer is convinient) ,water, glycerine Use conventional dental amalgam condensing procedures, manual & mechanical, but do not use ultrasonic amalgam condensers Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 112 CRAIG’s Restorative Dental Materials;12th ed
  • 111.
    Work in well ventilatedspaces Avoid carpeting dental operatories; decontamination of carpeting is very difficult If mercury comes in contact with skin, the skin should be washed with soap & water immediately Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 113 CRAIG’s Restorative Dental Materials;12th ed
  • 112.
    Amalgam scrap &materials contaminated with mercury or amalgam should not be incinerated or subjected to heat sterilization Adequate water spray & suction should be used during amalgam polishing & removal During the intra oral placement & condensation procedures, rubber dam & high volume evacuation should be used Eye protection , a disposable mask & gloves are now standard requirements for dental offices Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 114 CRAIG’s Restorative Dental Materials;12th ed
  • 113.
    Spent capsules &mercury contaminated cotton rolls or paper napkins should not be thrown out with regular trash, rather they should be stored in a tightly capped plastic container or closed plastic bag for separate disposal Perform yearly mercury determinations on all personnel regularly employed in dental offices Determine mercury vapors levels in operatories periodically Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Alert all personnel who handle mercury, especially during training of the potential hazard of mercury vapors & the necessity for observing good mercury & amalgam practices 115 Sturdevant’s Art & Science of Operative Dentistry; 5th ed
  • 114.
  • 115.
  • 116.
  • 117.
  • 118.
    The older generationof low-copper amalgams (before 1963) had a limited life span because they contained the gamma-2 phase that caused progressive weakening of the amalgam through corrosion Several clinical studies have demonstrated that high-copper amalgams can provide satisfactory performance for more than 12 years Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 120 Dental amalgam: An update
  • 119.
    This appears tobe true even for large restorations that replace cusps In addition, high-copper amalgams do not appear to require polishing after placement, as was recommended for low-copper amalgams, to increase their longevity Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 121 Dental amalgam: An update
  • 120.
    Plasmins et al.evaluated the long-term survival of multisurface restorations and found that extensive amalgam restoration had no influence on the survival rate J Dent Res. 1998;77:453–60 this is in accordance with the results of a retrospective study by Robins and Summitt, who found 50% survival rate for 11.5 years Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Oper Dent. 1988;13:54–7 122
  • 121.
    The satisfactory functioningof the extensive amalgam restorations over a long period of time results from the prevention of the most important traditional mechanical failure of amalgam restorations. These include marginal fracture, bulk fracture and tooth fracture. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 123 Dental amalgam: An update
  • 122.
    The zinc andcopper content of the alloy has been found to have a strong impact on the survival rates of amalgam restorations since it influences the corrosion resistance of the amalgam. High-copper amalgams has higher survival rates than conventional amalgams Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 124 Dental amalgam: An update
  • 123.
    ` • Letzel investigatedsurvival and modes of failure of amalgam restorations retrospectively. The leading mode of failure was bulk fracture (4.6%), followed by tooth fracture (1.9%) and marginal ridge fracture (1.3%). For other reasons, 0.8% Amalgam restorations: Survival, failures and causes of failure of Mater. restorations failed Dent the 1989;5:115–21 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 125
  • 124.
    ALTERNATIVES TO AMALGAM Metalalloys:Cast gold Gallium alloys TOOTH COLORED ALTERNATIVES Glass ionomer cements Composite resins Glass ionomer resin hybrids Compomers Ceramics Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Br Dent J 1997; 183: 11-14126
  • 125.
    Dr G VBlack Dr Michael Buonocore 127
  • 126.
    COMPOSITES….. • Aesthetically superior •Mercury-free • Strengthens the tooth by chemical bonding thereby reducing the chance of tooth fracture Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 128
  • 127.
    Safety of Compositeresin Br Dent J 1997; 183: 11-14 • Produce more cytotoxicity than amalgam in comparative in vitro tests • Classifiable as toxic restorative material Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion • Produce an inflammatory response in pulp when placed in test cavities in animals • Strongly allergenic • Inhibit RNA synthesis of cells 129
  • 128.
     Prospective clinicalstudies have shown comparable annual failure rates of both materials (Manhart et a!., 2004). • However, three recently published studies reported better longevity of amalgam restorations compared with composite restorations (Van Nieuwenhuysen et at, 2003; Berrtardo et at, 2007; Soncini at at, 2007). Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 130
  • 129.
    amalgam has agreater longevity than composite resin in posterior restorations Longevity of Composite Resin and Amalgam Restorations in Posterior Teeth: An Evidence-Based Review of the Literature DEN300Y – Community Dentistry, winter 2009 Numerous studies have shown amalgam restoration to last longer than resin composite restorations Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Amalgam-Resurrection & Redemption Quintessence Int 2001;32;525-535 131
  • 130.
    12-year Survival ofComposite vs. Amalgam Restorations NJ.M. Qpdam*, E.M. Bronkhorst, B.A.C. Loomans, and M.-C.D.NJ.M. Huysmans JDentRes 89(10):1063-l067, 2010 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 132
  • 131.
    Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recentadvances Sideeffects of mercury Durability Future Conclusion Survey of Practice Types Civilian General Dentists 32% Amalgam free Amalgam users 68% 133 Gen Dent 2005 Sep-Oct;53(5):369-75
  • 132.
    Frequency of PosteriorMaterials by Practice Type Amalgam Users 3% 7% 39% 51% Amalgam Amalgam Free Direct Composite 12% Indirect Composite Other Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 3% 8% 77% 134 Gen Dent 2005 Sep-Oct;53(5):369-75
  • 133.
    Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Doyou place fewer amalgams Manipulation than 5 years ago? Recent advances Sideeffects of 12% mercury No Durability Future Conclusion Yes Profile of Amalgam Users Civilian Practitioners Do you use amalgam in your practice? 22% No Yes 78% 88% 135 DPR 2005
  • 134.
    Review of ClinicalStudies (Failure Rates in Posterior Permanent Teeth) % Annual Failure 8 6 4 2 0 Amalgam Direct Comp Comp Inlays Longitudinal Ceramic CAD/CAM Inlays Inlays Gold Inlays & Onlays Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion GI Cross-Sectional 136 J Adhes Dentistry 2001 Spring;3(1):45-64.
  • 135.
    Review of ClinicalStudies (Failure Rates in Posterior Permanent Teeth) % Annual Failure 15 10 Standard Deviation Longitudinal and Cross-Sectional Data 5 AR T Tu nn el GI Am al ga Di m re ct Co Co mp m po m Co er m p Ce In la ra ys m ic In la CA ys D/ CA M Ca st G ol d 0 Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion 137 Oper Dent2004 Sep-Oct;29(5):481-508
  • 136.
  • 137.
    Future of dentalamalgam • The prediction that amalgam would not last until the end of the 20th century was wrong. Its unaesthetic appearance, its inability to bond tooth, concerns about the mercury and versatility of other materials have not led to the elimination of this inexpensive and durable material. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 139 Dental amalgam: An update
  • 138.
    Mercury released from dentalamalgam restorations does not contribute to systemic disease or systemic toxicological effects Allergic reactions to mercury from dental amalgam restorations have been demonstrated, but these are extremely rare Available scientific data do not justify the discontinuation of dental amalgam use from clinical practice or the replacement with other single-tooth restorative dental materials. There are cases where dental amalgam is the only choice with no other alternative Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Biocompatibility of Dental Amalgams-a review International Journal of Dentistry;Volume 2011, Article ID 981595,140 7 pages doi:10.1155/2011/981595
  • 139.
    possibility & perhaps probabilitythat dental amalgam will lose its importance in some more distant future the importance of dental amalgam at present and at least in the near future, the fact that dental amalgam is a material unique to the dental application CRITICAL ISSUES FOR Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion AMALGAM’S FUTURE DENTAL AMALGAM: REACTOR RESPONSE 141 Adv Dent Res 2(l):87-90, August, 1988
  • 140.
    the longevity ofdental restorations is dependent on many factors, including those related to materials, the dentist, and the patient Amalgam restorations are being replaced because of alleged adverse health effects and inferior aesthetic appearance Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Is it the end of the road for dental amalgam? A critical review Shenoy A; Conserv Dent. 2008 Jul;11(3):99-107 142
  • 141.
    TEN CLINICAL &LEGAL MYTHS OF ANTIAMALGAM Amalgam-Resurrection & Redemption –I Quintessence Int,2001;32:525-535 FACT 1. Teeth with amalgam restorations have acusps MYTH 1. Amalgams commonly cause fractured low incidence of fractured cusps MYTH 2. the majority of clinically sound amalgam FACT 2. the vast majority of teeth with amalgam restorations have recurrent caries; the majority of restorations do not have recurrent caries resin restorations do not Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion FACT 3. numerous studies restorations last as long as MYTH 3. Resin composite have shown that amalgam restorations longer than resin composite restorations amalgam restorations 143
  • 142.
    FACT 4. amalgamcan be bonded to teeth; often MYTH 4. amalgam cannot be bonded to teeth yielding bond strength higher than obtained by resin composite FACT 5.5. because of recent advances in materials & MYTH improvements in amalgam restorative material & technique,in recent years have been as dramatic as techniques most studies of resin composites are those in resin compositeof amalgam are not outdated ;most studies materials FACT 6.6. resin composite restorations are superiorcan MYTH like resin composite restorations amalgam to often be repaired composites can be repaired amalgam because Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion MYTH Amalgam’s is 100 yrs old; resin composite is FACT 7.7. amalgamlongevity is testament to its safety & much newer & thus better efficacy Amalgam-Resurrection & Redemption –I Quintessence Int,2001;32:525-535
  • 143.
    MYTH 8. TheADA refuseson the safety & efficacy of FACT 8. ADA’s statements to admit that mercury containing amalgam apparently unrelated to fear of dental amalgam are is unsafe for fear of lawsuits lawsuits MYTH neither the holds the patent for amalgam & FACT 9.9. The ADA ADA nor the ADA’S health receives a have ever each amalgam restoration foundationroyalty for received remuneration for any placed amalgam restoration ever placed Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion FACT 10. Dental amalgam has not been banned in any MYTH 10. Amalgam has been banned in Germany & country in the European union Sweden Amalgam-Resurrection & Redemption –I 145 Quintessence Int,2001;32:525-535
  • 144.
    DISCUSSION “OPERATIVE DENTISTRY Inon the threshold of postamalgam age , which is based on tooth colored restorative material” Krejci & Lutz;1995 Operative dentistry;1995,20,218-22 We should seek alternatives, if such alternatives can meet the health needs of our patients equally well or better Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Rory Hume; Quintessence Int,1996;27:2 146
  • 145.
    If composite resins,which can be costly ,pose the next biological risk in dentistry , what materials do we move to next?? Steven Duke; Compendium; Feb2003;vol24, no22 The future of dental amalgam is dependent on emotional & socioeconomic aspects that are different in each nation Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Roulet, Zimmer, Losche & Noack; Quintessence Int,1996;27:2 147
  • 146.
    As other materialsand techniques improve, the use of amalgam will likely continue to diminish, and it will eventually disappear from the scene Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Yet, amalgam continues to be the best bargain in the restorative armamentarium because of its durability and technique insensitivity J Conserv Dent. 2010 Oct;13(4):204-8. 148 Dental amalgam: An update
  • 147.
    “Amalgam will probablydisappear eventually, but its disappearance will be brought about by a better and more esthetic material, rather than by concerns over health hazards” “ When it does disappear, it will have served dentistry and patients well for more than 200 years” Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. Dental amalgam: An update 149
  • 148.
  • 149.
    CONCLUSION • Amalgam restorationshave served the profession well and will continue to do so in the years to come. In terms of longevity, they are probably superior to composite resins, especially when used for large restorations and cusp capping Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion J Conserv Dent. 2010 Oct;13(4):204-8. 151 Dental amalgam: An update
  • 150.
    The new highcopper single composition alloys offer superior properties but may not offer as good seal as older amalgams The use of amalgam can be continued as a material of choice if esthetics is not a concern. Introduction History Amalgam wars Classification Components setting reaction Manufacture Properties Manipulation Recent advances Sideeffects of mercury Durability Future Conclusion Prepare a tooth as conservative as possible, making access large enough only for removal of carious dentin and using resin sealants for non carious fissures J Conserv Dent. 2010 Oct;13(4):204-8. 152 Dental amalgam: An update
  • 151.
    Dental Amalgam willnot go away even if it were to be immediately discontinued as a restorative material. It will keep going , going & going 153
  • 152.
    REFERENCES • PHILLIPS’ Scienceof Dental Materials;11th ed Kenneth J. Anusavice • CRAIG’s Restorative Dental Materials;12th ed John M. Powers, Ronald L. Sakaguchi • Materials science for dentistry;9th ed B.W.Darvell • Sturdevant’s Art & Science of Operative Dentistry; 5th ed; Roberson, Heymann, Swift • fundamentals of operative dentistry, a contemporary approach; 3rd ed Summitt, Robbins, Hilton, Schwartz • Essentials of operative dentistry; I Anand Sherwood 154
  • 153.
    • Dental amalgam:An update J Conserv Dent. 2010 Oct-Dec; 13(4): 204–208 • Effect of admixed indium on the clinical success of amalgam restorations . • • operative dentistry journal1992 Sep-Oct;17(5):196-202 JPD 1981;VOL46;.5 Dental Materials, Volume 3, Issue 3, June 1987, Pages 117-120 • A Safe Protocol for AmalgamRemoval • • • • • Journal of Environmental and Public Health;Volume 2012 BDJ;VOL.183;NO.1;JULY,1997 Dent Mat Mar 2001 17 (2), 142-8 Quint Int, Mar'99, 30(3) 185-91 DM, Volume 6, Issue 4, October 1990, Pages 256-265 Br Dent J. 2009 Jan 24;206(2):E3 • Immediate hypersensitivity reaction associated with the mercury component of amalgam restorations • • Br Dent J. 2008 Nov 22;205(10):547-50 The mercury enigma in dentistry; JADA,VOL.92,June 1976 Mercury toxicity in the dental office: a neglected problem JADA,Vol.92,June 1976 155
  • 154.
    • Br DentJ 1997;182;293-297 • J Dent Res. 1998;77:453–60 • Oper Dent. 1988;13:54–7 • Amalgam restorations: Survival, failures and causes of failure Dent Mater. 1989;5:115–21 • Br Dent J 1997; 183: 11-14 • Longevity of Composite Resin and Amalgam Restorations in Posterior Teeth: An Evidence-Based Review of the Literature DEN300Y – Community Dentistry, winter 2009 • Amalgam-Resurrection & Redemption Quintessence Int 2001;32;525-535 • 12-year Survival of Composite vs. Amalgam Restorations JDentRes 89(10):1063-l067, 2010 • Review of the clinical survival of direct and indirect restorations in posterior teeth of the permanent dentition Oper. Dent. 2004 Sep-Oct;29(5):481-508 • Survey of general dentists regarding posterior restorations, selection criteria, and associated clinical problems. Gen Dent 2005 Sep-Oct;53(5):369-75; quiz 376, 367-8. 156
  • 155.
    • • Longevity of restorationsin posterior teeth and reasons for failure J Adhes Dentistry 2001 Spring;3(1):45-64. Review of the clinical survival of direct and indirect restorations in posterior teeth of the permanent dentition Oper Dent2004 Sep-Oct;29(5):481-508 Biocompatibility of Dental Amalgams-a review International Journal of Dentistry Volume 2011, Article ID 981595, 7 pages • DENTAL AMALGAM: REACTOR RESPONSE Adv Dent Res 2(l):87-90, August, 1988 • Is it the end of the road for dental amalgam? A critical review Shenoy A; Conserv Dent. 2008 Jul;11(3):99-107 • Amalgam-Resurrection & Redemption –I Quintessence Int,2001;32:525-535 • • • Operative dentistry;1995,20,218-22 Quintessence Int,1996;27:2 Steven Duke; Compendium; Feb2003;vol24, no22 157
  • 156.

Editor's Notes

  • #13 With recommendations of no touch procedures for mercury mercury n alloy dispensers are replaced.
  • #71 2) :.. 2 is also available. Gallium GF causes as a powder and contains; (by wt) - - Ag 50%, Sn-25.7%, Cu - 15%, Pd -9% and traces - 0.9%. It is also available as liquid containing Ga-65%, In - 18.85%, tin - 16% and traces -0.5%.
  • #85 4META-METHACRYLOXY TRIMELLITATE ANHYDRIDE