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Silver amalgam /certified fixed orthodontic courses by Indian dental academy


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Welcome to Indian Dental Academy …

Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients

State of the art comprehensive training-Faculty of world wide repute &Very affordable.

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  • 1. Dental amalgam INDIAN DENTAL ACADEMY Leader in Continuing Dental Education
  • 2. Contents1. Introduction2. History3. Advantages and disadvantages4. Classification5. composition6. Purpose of each ingredient7. Manufacturing of alloy8. Setting reaction9. Properties10. Gallium alloys
  • 3. 1. Manipulation2. Failures3. Amalgam bonding4. Combi-restorations5. Conclusion6. references
  • 4. Introduction► Amalgam : alloy that contains mercury as one of its constituent► Amalgam: derived from greek word malagma= emollient malassein= soften► Alloy : latin word alligare= to combine
  • 5. History► 1STform of amalgam developed by M.Taveau( 1826) in Paris.► Crawcour brothers(1833) introduced it in dental profession . Called Royal Mineral Succedaneum .► Amalgam War: 1840-1850► Dr.G.V.Black(1896):► ADA Specification 1 in 1929
  • 6. Advantages► Durable► High compressive strength► Insoluble in the fluids of mouth► Adaptability to walls of preparation► Least time consuming to place► Ability to corrode- decreased microleakage► Ability to take polish
  • 7. Disadvantages► Not tooth colored► Does not bond to tooth structure► Lack of edge strength► High conductivity► Mercury toxicity
  • 8. Classification► No of alloys:1. Binary alloys– silver and tin2. Ternary: silver , tin and copper3. Quarternary: silver ,tin, copper, indium► Powder particle size:1. Micro cut2. Fine cut3. Coarse cut
  • 9. ► Based on copper content1. Low copper: <6%Cu2. High copper: >6% Cu admixed: 28% single composition- 13-30%
  • 10. ► Shape of powdered particle1. Irregular: spindles, shavings2. Spherical3. Spheroidal Based on zinc:1. Zinc containing alloy: > 0.01% Zn2. Zinc free: < .01% Zn
  • 11. Based on addition of noble metals 1st generation: 3 parts silver+1 part tin peritectic► 2nd generation: copper is added upto 4%► 3rd generation : silver copper eutectic alloy + original alloy► 4th generation : alloying of copper to silver and tin upto 29%► 5th generation : silver, copper ,tin, indium► 6th generation: alloying palladium 10%, silver62%, copper 28%--- eutectic lathecut blended into 1st gen in ratio of 1:2
  • 12. Composition► Conventional low copper alloySilver: 68-72%Tin: 25-27%Copper: 2-6%Zinc: 0-3%
  • 13. Admixed alloy►Mixture of lathe cut low copper alloy and spherical alloy►Silver: 60-69%►Tin: 17-25%►Copper: 9-20%►zinc: 0-1%
  • 14. Single composition Each particle has same composition► silver:40-60%► Tin: 22-30%► Copper: 13-30%► Indium: 0-5%► Palladium: 0-1%
  • 15. Functions of each ingredients► Silver:1. Increases strength2. Increase setting expansion3. Decreases flow4. Improves color5. Setting time decreased6. Resist tarnish and corrosion
  • 16. Tin► Advantages:1. Decreases expansion2. Helps in amalgamation► Disadvantages:1. Decreases strength2. Setting will be slow3. Increases flow4. Tarnish and corrosion
  • 17. copper► Advantages:1. Increases strength and hardness2. Decreases flow3. Setting will be quick► Disadvantages:1. Increases expansion2. Can be tarnished3. Brittleness
  • 18. Zinc► Advantages:1. Scavenger/ de-oxidiser2. Helps in workability3. Quickens the setting time4. Increases ultimate strength► Disadvantages:1. Increases expansion in presence of moisture2. Diminishes edge strength
  • 19. Mercury► Advantages:1. Gives plasticity and softness2. Binds the particles together3. Essential for setting reaction and hardening► Disadvantages:1. Mercury toxicity
  • 20. Selenium: Improves the biocompatability of amalgam (Sato and Kumei-1982)► Indium: Decreases the mercury vapour released during mastication( Dowell and Youdelis 1992)► Platinum: Hardens alloy and corrosion resistant► Palladium: Hardens and whitens alloy
  • 21. Manufacturing of alloyLathecut:Ingot: 20-25 cm long and 3-8 cm diameterHomogenised anneal of ingot: oven 400C for 6-8 hrsBallmilling : to reduce size particle treatment with acids to improve the reactivityAging process life improve shelf
  • 22. Spherical alloy► Atomised: liquid alloy into a closed chamber filled with inert gas► Size: 2-43 microns► Acid treatment
  • 23.
  • 24.
  • 25. Setting reaction► Amalgamation occurs when Hg contacts Ag-Sn► Low copper alloys:► Ag3Sn + Hg ---Ag2Hg3 +Sn8Hg+Ag3SnMicrostructure:► Unreacted particles surrounded by matrix of gamma1 and gamma2,► Voids
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  • 27.
  • 28. High copper admixed► 1part silver-copper eutectic alloy + 2 parts silver tin alloy► Ag3Sn +Ag-cu+ Hg ---Ag2Hg3 +Sn8Hg +Ag3Sn + Agcu►Later,►Sn8Hg +Ag-Cu- Cu6Sn5+ Ag2Hg3►Gamma2 is eliminated►Core :Ag3Sn and Ag-cu surrounded by a halo of Cu6Sn5(n)
  • 29.
  • 30.
  • 31. Single composition► Ag3Sn + Cu3Sn+ HgCu6Sn5 +Ag2Hg3► Core: Ag3Sn and Ag-Cu► Matrix: Ag2Hg3► Cu6Sn5 is present in gamma1 matrix rather than as halo around Ag-Cu
  • 32.
  • 33.
  • 34. Dimensional changes► ADA specification1: -15Micron to + 20 microns at 37c between 5 min and 24hrs after beginning of trituration► Theory of dim.change:1. Initial contraction2. Expansion3. Delayed contraction
  • 35. ► Severe contraction:1. Microleakeage2. Plaque accumulation3. Secondary caries► Excessive expansion1. Pressure on pulp2. Post op sensitivity3. Protrusion of restoration
  • 36.
  • 37. Factors affecting dimensional change► Constituents: more gamma- more exp tin– less exp► Mercury: more ->expansion high► Particle size: smaller size-> more contraction► Trituration: more energy, longer time- contraction► Condensation: more forces  contraction► Particle shape: irregular expansion
  • 38. Creep► Creep: time dependent plastic strain of material under static load or constant stress► ADA specification : 3% or less► Low copper alloys: 0.8% to 8%► High copper alloys: 0.1%► Factors: 1. influence of microstructures 2. manipulative variables► High creep: more marginal detoriation
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  • 41. Compressive strength► Satisfactory compressive strength: 310 MPa► After 7 days , comp strength of high copper alloys is more than low copper alloys► After 1hr, single composition alloy strength is double that of other alloys► Amalgam is weak in tension
  • 42.
  • 43. Factors affecting strength► Trituration: more energy more strength► Mercury: weakest phase► Condensation: more forcemore strength► Porosity: decreases strength► Particle shape: regular and smooth  strong► Particle size: smaller diameter greater strength► Corrosion: decreases strength► Gamma2 2nd weakest phase
  • 44. Rate of attaining strength► Accelerated strength:1. Decreased particle size.2. More trituration energy3. More condensation energy4. Smooth and regular particles5. Homogenisation heat treatment6. Minimum mercury in the mix
  • 45. Tarnish and corrosion► Tarnish: surface discoloration on metal or even slight loss or alteration of the surface finish or luster.► Corrosion: actual detoriation of ametal by reaction with its environment► Active corrosion: interface between tooth and restoration crevice corrosion► selfsealing
  • 46.
  • 47. ► Both low and high copper corrosion products are oxides and chlorides of tin► In high copper amalgam: corrosion process is limited,since n (Cu6Sn5) is least susceptible to corrosion than gamma2► Gold restoration when placed in contact with an amalgam,large difference in EMFcorrosion
  • 48. Other propertiesEffect of moisture contamination:► Zinc-containing amalgam contaminated by moisture , a large expansiondelayed expansion or secondary expansion► H2O + Zn ZnO2 +H2 (gas)► This hydrogen gas collects in restoration  expansion, protrusion , increased creep, increased microleakage, corrosion, pain.
  • 49. Marginal adaptation► Tendency to minimise microleakeage –self sealing► Due to corrosion products which seals restoration► Low copper alloys–> 2-3 months► High copper alloys10-12 months► Problems due to improper adaptation1. Marginal detoriation2. Accumulation of debris3. Recurrent caries4. Post op sensitivity
  • 50. Gallium alloy► Alloy: Liquid:Silver60%Tin 25% Gallium 62%copper 13% Iridium 25%Palladium 20% Tin 25%
  • 51. Gallium alloys► Puttkammer 1928► Comp.strength and tensile strength comparable to amalgam► Creep—0.09%► Sets early polishing can be done on same day► They expand after mixing, better marginal seal► Sticks to walls of capsule.► More costly.
  • 52.
  • 53. Copper amalgam► Copper and mercury► Antiseptic► Composion: 70%Hg , 30% copper-  pellet► Heated in a spoon,then triturated► Adv: increased hardeness, not effected by moisture, no creepDisadv: discoloration and shrinkage
  • 54. Manipulation1. Choice of alloy and mercury2. Proportioning3. Trituration4. Mulling5. Condensation6. Burnishing7. Carving8. Finishing and polishing
  • 55. Choice of alloy and mercury► Selection of alloy depend on: setting time, particle size and shape, composition, presence or absence of zinc.► 90% amalgams placed are high Cu ,admixed alloys► Adv: no gamma2, low creep high early strength good corrosion resistance decreased marginal failure► Zinc containing and zinc free:
  • 56. Proportioning of alloy and mercury► Preferably done by weight rather than volume► Mode of supply: powder particles, pellet ,disposable capsules, reusable capsules► Dispensers with preweighed tablets and Hg containers are available► NO TOUCH :preweighed capsules are available with alloy and Hg seperated by membrane.► Size of mix:400,600,800 +appropriate Hg--- color coded
  • 57. Contd► Reusable capsules :1.friction fit 2. screw type—better► Disposable capsules should not be reused► Increasing dryness techique: 52-53% Hg very plastic mix, large restorations, multiple auxillary means of retention► Eames technique: 48-50% Hg
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  • 59. Trituration► Act or rubbingObjectives:► Achieve workable mass► Removes oxides from powder particles► Pulverize pellets to particles► Dissolve particles of powder in Hg► Reduce particle size► Keep gamma1 matrix crystals minimal and evenly distribute
  • 60. Triturators► 2 types: hand and mechanical► Hand: mortar and pestle► Mechanical: amalgamators► Has plastic or metal capsule, metal or plastic ball or pestle.► Hoods.► 3 basic movements of pestle: centrifugal figure 8 straight line
  • 61. Contd► Coherence time: minimum mixing time required for an amlagam to form a single coherent pellet.► Effective trituration depends on duration and speed of mixing.► Duration:► Speed: low :3200-3400 cycles/ min medium:3700-3800 cycles /min high :4000-4400 cycles/min► Spherical or irregular low copper: low speed► High copper alloys: high speed
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  • 63.
  • 64. Trituration energy► Trituration(work) = motor speed * time * capsule-pestle action► Trituration Energy:1. Speed or no. of unit movements per unit time2. Thrust of the movement3. Weight of the capsule or pestle4. Difference in size between pestle and capsule5. Time
  • 65. Mulling► Continuation of trituration► Provides homogenicity to the mix► 2 ways:1. Mix is enveloped in dry piece of rubberdam and rubbed betweem 1st finger and thumb.2. After trituration,pestle is removedfrom capsule and mix is triturated for 2-3 sec.► This assures cleaning of capsule walls of remnants of mix and developing a single coherent mix
  • 66. Type of mixTest for correct mix:Normal mix:May be warmSmooth and soft Overtrituration: Alloy will be hot Hard to remove from the capsule Shiny wet and soft Undertrituration1. Alloy will be dry2. Will crumble if dropped from approximately 30cm
  • 67.
  • 68. condensation► Continuation of trituration process► Purpose:1. Squeezes unreacted Hg out of increments2. This Hg squeezed to surface binds further sucessive increments3. Forces used brings stronger phase together boosting final strength4. Adapts plastic mix to the walls of preparation5. Decreases no. of voids
  • 69. Condensation► Should start immediately after trituration► 3-3 ½ min► Further condensation causes cracks► 3 ways: 1. hand condensation 2. mechanical: a. vibratory b. impact 3. ultrasonic► Pressure inversely proportional to square of surface area
  • 70.
  • 71. Types of condensors► Shapes:1. Round2. Parallelogram3. Diamond4. EllipticalVarious contours:1. Flat2. Concave3. angular
  • 72. Round condensors► 3 instruments of diameter 15,25,35► Angle 10 degrees to shaft► Nibs 7mm long► 15-25 diameter: compressing amalgam in small pits► 35 diameter: final heavy pressure in occlusal surface of molars
  • 73. Parallelogram condensors► 2 pairs► Smaller: 30*10- 7-10 10* 30-7-10 proximo occlusal in bicuspids and molars► Larger: 35* 15- 7-10 15*35-7-10 molars
  • 74.
  • 75. ► Sweeney’s instrumentshas sharp angles condensing amalgam into angles
  • 76. condensation► Face or nib should be flat or smooth► Atleast 6 pounds should be used► Amalgam is inserted into cavity in small increments and condensed with smaller instruments.► Minimises voids and adapts to smaller details► Near surface, larger consensors are used.
  • 77. Nonspherical alloys► Force applied at 45deg to walls and floor► Next increment at 90 deg to previous one► Centre to periphery condensation► Excess Hg which comes to surface is excavated and discarded.
  • 78. Spherical alloys► Large increments► Largest condensor that will fit the cavity, to prevent lateral escape of spherical part► Particles have tendency to roll over► Less energy than nonspherical
  • 79. Final appearanceConcave amalgam surface should face condensor indicating proper angulation and application of forcesCondensed increment should not be indententedby further cond. force showing a coherent mass
  • 80. Blotting mix► An overdried amalgam mix is condensed heavily on the restoration using large condensors► Blots excess Hg from critical marginal and surface area of restoration
  • 81. Burnishing or surfacing► Process of rubbing, usually performed to make a surface shiny► Light strokes, from amalgam to tooth surface► Objectives:1. Dec size and no. of voids on critical areas and margins2. Brings excess Hg to surface3. Adapts amalgam to cavosurface anatomy► Precarve and post carve burnishing
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  • 83. carving► Anatomical sculpting of amalgam.► Begins immediately after condensation and precarve burnishing► Objectives:1. Produce restoration with no under hangs2. Proper physiological contours and contacts3. Adequate and compatible marginal ridges4. Physiological embrasures5. Functional non interfering occlusal anatomy6. Enhance periodontal health and integrity
  • 84. Carving - steps► Initial carving– discoid carver removes extra bulk► Accessible embrasures : sharp explorer or lateral edge of hollenback carver► Creating triangular fossa: discoid /cleoidThis coupled with previous procedure will erect marginal ridges► Margination: discoid /hollenback removes marginal flash, from tooth to amalgam
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  • 86. Contd► Facial and lingual grooves: hollenback, chisel, cleoid /discoid► Cusp ridges and inclined planes: hollenback placed concurrently on amalgam and adjacent tooth surface ,lateral movement with intact tooth as guide► Anatomic grooves: anatomic burnisher► Post carve burnishing : light forces not done in fast setting amalgams
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  • 89. Finishing and polishing► Finishing: process which continues the carving objectives, removes flash and overhangs , corrects minimal underhangsDone at placement appointmentPolishing: smoothing the surface to a point of high gloss or lusture.Creates corrosion resistant layer by removing scratches & irregular surfaceAfter 24hrs preferably
  • 90. objectives1. Conversion of superficial amalgam into relatively inert layer galvanically2. Removal of superficial scratches and irregularities3. Minimises concentration cell corrosion
  • 91. contd► Gross smoothening: finishing burs► Polishing agents: Tinoxide, Zincoxide ,PPT chalk► Polishing convex surfaces like facial ,lingual proximal: progressive finer disks, abrasive impregnated cups► Concave surfaces : Abr impregnated rubber points► Contact areas and gingival embrasures: linen polishing strips or dental tape► Abundance of air-coolant and intermittent contact
  • 92.
  • 93. Failures of amalgam► Visual level1. Marginal fracture2. Bulk fracture3. Dimensional change4. Secondary caries5. Tooth fracture► Microstructural level1. Corrosion and tarnish2. Stresses► Pain following restoration
  • 94. Reasons for failures► Defective cavity preparation: 56% of failures► Defective manipulation: 42% failures► Defective matrix adaptation► Defective materials
  • 95. Marginal failures
  • 96.
  • 97.
  • 98.
  • 99.
  • 100.
  • 101. Defective cavity preparation► Insufficient occlusal extension► Under extension of proximal box► Over extended cavity preparation► Cavity depth► Floor► No butt joint► Fracture of isthmus► Sharp axiopulpal line angle► Incomplete removal of caries► Hyperemia of pulp► Additional retentive forms to be in dentin
  • 102. Defective amalgam manipulation► Improper condensation► Incorrect mercury alloy ratio► Contamination► Defective finishing and polishing
  • 103. Post operative pain► High points► Delayed expansion► Inadequate pulp protection► Continuous leakage around filling
  • 104. Finishing and polishing► Overcarving► Failure to polish► Temperatures greater than 65c  mercury is released from amalgam► Amalgam which have greater tendency for tarnish and corrosion
  • 105. Amalgam bonding► Amalgam is hydrophobic while enamel and dentin are hydrophilic.► Wetting agent should have both the properties► 4-methyloxy ethyl trimellitic anhydride► Thick layers of bonding agents(10-50 microns) are applied about 8-10 times► Amalgam bond, scotch bond MP, All Bond 2,
  • 106. Bonding interface► Tag formation► Chemical binding to the inorganic or org components of dentin► Formation of hybrid layer of reinforced dentin
  • 107. Advantages► Dentin sealing► Resistance and retention form increased► Improves marginal seal► Use of retention pins eliminated► Microleakeage ,recurrent caries, postoperative sensitivity reduced► Cavity can be made conservatively► Cost effective for extensively carious tooth
  • 108. Limitations► Technique sensitive► Bond strength is reduced after some years► Cost of bonded amalgam is more than nonbonded
  • 109. Gallium alloy► Alloy: Liquid:Silver60%Tin 25% Gallium 62%copper 13% Iridium 25%Palladium 20% Tin 25%
  • 110. Gallium alloys► Puttkammer 1928► Comp.strength and tensile strength comparable to amalgam► Creep—0.09%► Sets early polishing can be done on same day► They expand after mixing, better marginal seal► Sticks to walls of capsule.► More costly.
  • 111.
  • 112. conclusion
  • 113. References1. Dr .G.V.Blacks Operative dentistry2. Operative Dentistry By Mc Gehee3. Dental materials by Philips4. Craigs restorative dental materials5. Dental materials by Soratur6. Marzouk7. Charbeneau8. Restoration of tooth Str: G.J.Mount
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  • 115.
  • 116. Thank you