Dental amalgam           INDIAN DENTAL ACADEMY     Leader in Continuing Dental Education        www.indiandentalacademy.co...
Contents1.    Introduction2.    History3.    Advantages and disadvantages4.    Classification5.    composition6.    Purpos...
1.   Manipulation2.   Failures3.   Amalgam bonding4.   Combi-restorations5.   Conclusion6.   references               www....
Introduction► Amalgam     : alloy that contains mercury as one of  its constituent► Amalgam: derived from greek word      ...
History► 1STform of amalgam developed by  M.Taveau( 1826) in Paris.► Crawcour brothers(1833) introduced it in  dental prof...
Advantages►   Durable►   High compressive    strength►   Insoluble in the fluids of    mouth►   Adaptability to walls of  ...
Disadvantages► Not tooth colored► Does not bond to tooth structure► Lack of edge strength► High conductivity► Mercury toxi...
Classification►    No of alloys:1.   Binary alloys– silver and tin2.   Ternary: silver , tin and copper3.   Quarternary: s...
►  Based on copper content1. Low copper: <6%Cu2. High copper: >6% Cu         admixed: 28%         single composition- 13-3...
►    Shape of powdered particle1.   Irregular: spindles, shavings2.   Spherical3.   Spheroidal      Based on zinc:1.   Zin...
Based on addition of noble              metals      1st generation: 3 parts silver+1 part tin    peritectic►    2nd genera...
Composition► Conventional low copper alloySilver: 68-72%Tin: 25-27%Copper: 2-6%Zinc: 0-3%              www.indiandentalaca...
Admixed alloy►Mixture of lathe cut low copper alloy and spherical alloy►Silver: 60-69%►Tin: 17-25%►Copper: 9-20%►zinc: 0-1...
Single composition Each particle has same composition► silver:40-60%► Tin: 22-30%► Copper: 13-30%► Indium: 0-5%► Palladium...
Functions of each ingredients►    Silver:1.   Increases strength2.   Increase setting expansion3.   Decreases flow4.   Imp...
Tin►    Advantages:1.   Decreases expansion2.   Helps in amalgamation►    Disadvantages:1.   Decreases strength2.   Settin...
copper►    Advantages:1.   Increases strength and hardness2.   Decreases flow3.   Setting will be quick►    Disadvantages:...
Zinc►    Advantages:1.   Scavenger/ de-oxidiser2.   Helps in workability3.   Quickens the setting time4.   Increases ultim...
Mercury►    Advantages:1.   Gives plasticity and softness2.   Binds the particles together3.   Essential for setting react...
Selenium: Improves the biocompatability of  amalgam (Sato and Kumei-1982)► Indium:   Decreases the mercury vapour  release...
Manufacturing of alloyLathecut:Ingot: 20-25 cm long and 3-8 cm diameterHomogenised anneal of ingot: oven 400C for 6-8 hrsB...
Spherical alloy► Atomised: liquid alloy  into a closed chamber  filled with inert gas► Size: 2-43 microns► Acid treatment ...
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Setting reaction► Amalgamation occurs when Hg contacts Ag-Sn► Low copper alloys:► Ag3Sn + Hg ---Ag2Hg3 +Sn8Hg+Ag3SnMicros...
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High copper admixed► 1part silver-copper eutectic alloy + 2 parts silver tin  alloy► Ag3Sn +Ag-cu+ Hg ---Ag2Hg3          ...
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Single composition► Ag3Sn + Cu3Sn+ HgCu6Sn5 +Ag2Hg3► Core: Ag3Sn and Ag-Cu► Matrix: Ag2Hg3► Cu6Sn5 is present in gamma1 m...
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Dimensional changes►    ADA specification1:     -15Micron to + 20     microns at 37c between     5 min and 24hrs after    ...
►    Severe contraction:1.   Microleakeage2.   Plaque accumulation3.   Secondary caries►    Excessive expansion1.   Pressu...
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Factors affecting dimensional               change► Constituents:   more gamma- more exp                   tin– less exp► ...
Creep► Creep: time dependent plastic strain of         material under static load or constant         stress► ADA specific...
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Compressive strength► Satisfactory compressive strength: 310 MPa► After 7 days , comp strength of high copper  alloys is m...
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Factors affecting strength► Trituration: more energy more strength► Mercury: weakest phase► Condensation: more forcemore...
Rate of attaining strength►    Accelerated strength:1.   Decreased particle size.2.   More trituration energy3.   More con...
Tarnish and corrosion► Tarnish: surface discoloration on metal or  even slight loss or alteration of the surface  finish o...
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► Both low and high copper corrosion products are oxides and chlorides of tin► In high copper amalgam: corrosion process ...
Other propertiesEffect of moisture contamination:► Zinc-containing amalgam contaminated by  moisture , a large expansiond...
Marginal adaptation►    Tendency to minimise microleakeage –self     sealing►    Due to corrosion products which seals    ...
Gallium alloy►  Alloy:                         Liquid:Silver60%Tin 25%                           Gallium 62%copper 13%    ...
Gallium alloys► Puttkammer 1928► Comp.strength and tensile strength  comparable to amalgam► Creep—0.09%► Sets early polis...
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Copper amalgam► Copper and mercury► Antiseptic► Composion: 70%Hg , 30% copper-  pellet► Heated in a spoon,then triturated...
Manipulation1.   Choice of alloy and mercury2.   Proportioning3.   Trituration4.   Mulling5.   Condensation6.   Burnishing...
Choice of alloy and mercury►   Selection of alloy depend on:    setting time, particle size and shape,    composition, pre...
Proportioning of alloy and mercury► Preferably done by weight rather than volume► Mode of supply: powder particles, pellet...
Contd► Reusable capsules :1.friction fit                       2. screw type—better► Disposable capsules should not be reu...
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Trituration►  Act or rubbingObjectives:► Achieve workable mass► Removes oxides from powder particles► Pulverize pellets to...
Triturators► 2 types: hand  and mechanical► Hand: mortar and pestle► Mechanical: amalgamators► Has plastic or metal capsul...
Contd►   Coherence time: minimum mixing time required for an    amlagam to form a single coherent pellet.►   Effective tri...
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www.indiandentalacademy.com
Trituration energy►    Trituration(work) = motor speed *              time * capsule-pestle action►    Trituration Energy:...
Mulling►    Continuation of trituration►    Provides homogenicity to the mix►    2 ways:1.   Mix is enveloped in dry piece...
Type of mixTest for correct mix:Normal mix:May be warmSmooth and soft      Overtrituration:      Alloy will be hot      Ha...
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condensation►    Continuation of trituration process►    Purpose:1.   Squeezes unreacted Hg out of increments2.   This Hg ...
Condensation► Should start immediately after trituration► 3-3 ½ min► Further condensation causes cracks► 3 ways: 1. hand c...
www.indiandentalacademy.com
Types of condensors►   Shapes:1. Round2. Parallelogram3. Diamond4. EllipticalVarious contours:1. Flat2. Concave3. angular ...
Round condensors► 3 instruments of diameter 15,25,35► Angle 10 degrees to shaft► Nibs 7mm long► 15-25 diameter: compressin...
Parallelogram condensors► 2 pairs► Smaller: 30*10- 7-10           10* 30-7-10      proximo occlusal in bicuspids and  mola...
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► Sweeney’s instrumentshas sharp angles  condensing amalgam  into angles                www.indiandentalacademy.com
condensation► Face or nib should be flat or smooth► Atleast 6 pounds should be used► Amalgam is inserted into cavity in sm...
Nonspherical alloys► Force applied at 45deg  to walls and floor► Next increment at 90  deg to previous one► Centre to peri...
Spherical alloys► Large increments► Largest condensor that  will fit the cavity, to  prevent lateral escape  of spherical ...
Final appearanceConcave amalgam surface should face condensor indicating proper angulation and application of forcesConden...
Blotting mix► An overdried amalgam mix is condensed  heavily on the restoration using large  condensors► Blots excess Hg f...
Burnishing or surfacing►    Process of rubbing, usually performed to make a surface     shiny►    Light strokes, from amal...
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carving►    Anatomical sculpting of amalgam.►    Begins immediately after condensation and precarve     burnishing►    Obj...
Carving - steps► Initial carving– discoid carver removes extra  bulk► Accessible embrasures : sharp explorer or lateral  ...
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Contd► Facial and lingual grooves: hollenback, chisel,  cleoid /discoid► Cusp ridges and inclined planes: hollenback  plac...
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Finishing and polishing► Finishing: process which continues the carving objectives, removes flash and overhangs , corrects...
objectives1. Conversion of superficial amalgam into   relatively inert layer galvanically2. Removal of superficial scratch...
contd► Gross smoothening: finishing burs► Polishing agents:    Tinoxide, Zincoxide ,PPT chalk► Polishing convex surfaces l...
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Failures of amalgam►    Visual level1.   Marginal fracture2.   Bulk fracture3.   Dimensional change4.   Secondary caries5....
Reasons for failures► Defective cavity preparation: 56% of failures► Defective manipulation:  42% failures► Defective matr...
Marginal failures  www.indiandentalacademy.com
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Defective cavity preparation►   Insufficient occlusal extension►   Under extension of proximal box►   Over extended cavity...
Defective amalgam manipulation► Improper condensation► Incorrect mercury alloy ratio► Contamination► Defective finishing a...
Post operative pain► High points► Delayed expansion► Inadequate pulp protection► Continuous leakage around                ...
Finishing and polishing► Overcarving► Failure to polish► Temperatures greater than 65c  mercury  is released from amalgam...
Amalgam bonding► Amalgam is hydrophobic while enamel and  dentin are hydrophilic.► Wetting agent should have both the  pro...
Bonding interface► Tag formation► Chemical binding to the inorganic or org  components of dentin► Formation of hybrid laye...
Advantages► Dentin sealing► Resistance and retention form increased► Improves marginal seal► Use of retention pins elimina...
Limitations► Technique sensitive► Bond strength is reduced after some years► Cost of bonded amalgam is more than nonbonded...
Gallium alloy►  Alloy:                         Liquid:Silver60%Tin 25%                           Gallium 62%copper 13%    ...
Gallium alloys► Puttkammer 1928► Comp.strength and tensile strength  comparable to amalgam► Creep—0.09%► Sets early polis...
www.indiandentalacademy.com
conclusion  www.indiandentalacademy.com
References1.   Dr .G.V.Blacks Operative dentistry2.   Operative Dentistry By Mc Gehee3.   Dental materials by Philips4.   ...
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Thank you  www.indiandentalacademy.com
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Silver amalgam /certified fixed orthodontic courses by Indian dental academy

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Silver amalgam /certified fixed orthodontic courses by Indian dental academy

  1. 1. Dental amalgam INDIAN DENTAL ACADEMY Leader in Continuing Dental Education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. Contents1. Introduction2. History3. Advantages and disadvantages4. Classification5. composition6. Purpose of each ingredient7. Manufacturing of alloy8. Setting reaction9. Properties10. Gallium alloys www.indiandentalacademy.com
  3. 3. 1. Manipulation2. Failures3. Amalgam bonding4. Combi-restorations5. Conclusion6. references www.indiandentalacademy.com
  4. 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 www.indiandentalacademy.com
  5. 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 www.indiandentalacademy.com
  6. 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 www.indiandentalacademy.com
  7. 7. Disadvantages► Not tooth colored► Does not bond to tooth structure► Lack of edge strength► High conductivity► Mercury toxicity www.indiandentalacademy.com
  8. 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 www.indiandentalacademy.com
  9. 9. ► Based on copper content1. Low copper: <6%Cu2. High copper: >6% Cu admixed: 28% single composition- 13-30% www.indiandentalacademy.com
  10. 10. ► Shape of powdered particle1. Irregular: spindles, shavings2. Spherical3. Spheroidal Based on zinc:1. Zinc containing alloy: > 0.01% Zn2. Zinc free: < .01% Zn www.indiandentalacademy.com
  11. 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 www.indiandentalacademy.com
  12. 12. Composition► Conventional low copper alloySilver: 68-72%Tin: 25-27%Copper: 2-6%Zinc: 0-3% www.indiandentalacademy.com
  13. 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% www.indiandentalacademy.com
  14. 14. Single composition Each particle has same composition► silver:40-60%► Tin: 22-30%► Copper: 13-30%► Indium: 0-5%► Palladium: 0-1% www.indiandentalacademy.com
  15. 15. Functions of each ingredients► Silver:1. Increases strength2. Increase setting expansion3. Decreases flow4. Improves color5. Setting time decreased6. Resist tarnish and corrosion www.indiandentalacademy.com
  16. 16. Tin► Advantages:1. Decreases expansion2. Helps in amalgamation► Disadvantages:1. Decreases strength2. Setting will be slow3. Increases flow4. Tarnish and corrosion www.indiandentalacademy.com
  17. 17. copper► Advantages:1. Increases strength and hardness2. Decreases flow3. Setting will be quick► Disadvantages:1. Increases expansion2. Can be tarnished3. Brittleness www.indiandentalacademy.com
  18. 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 www.indiandentalacademy.com
  19. 19. Mercury► Advantages:1. Gives plasticity and softness2. Binds the particles together3. Essential for setting reaction and hardening► Disadvantages:1. Mercury toxicity www.indiandentalacademy.com
  20. 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 www.indiandentalacademy.com www.indiandentalacademy.com
  21. 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 towww.indiandentalacademy.com life improve shelf
  22. 22. Spherical alloy► Atomised: liquid alloy into a closed chamber filled with inert gas► Size: 2-43 microns► Acid treatment www.indiandentalacademy.com
  23. 23. www.indiandentalacademy.com
  24. 24. www.indiandentalacademy.com
  25. 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 www.indiandentalacademy.com
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  28. 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) www.indiandentalacademy.com
  29. 29. www.indiandentalacademy.com
  30. 30. www.indiandentalacademy.com
  31. 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 www.indiandentalacademy.com
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  34. 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 www.indiandentalacademy.com
  35. 35. ► Severe contraction:1. Microleakeage2. Plaque accumulation3. Secondary caries► Excessive expansion1. Pressure on pulp2. Post op sensitivity3. Protrusion of restoration www.indiandentalacademy.com
  36. 36. www.indiandentalacademy.com
  37. 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 www.indiandentalacademy.com
  38. 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 www.indiandentalacademy.com
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  41. 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 www.indiandentalacademy.com
  42. 42. www.indiandentalacademy.com
  43. 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 www.indiandentalacademy.com
  44. 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 www.indiandentalacademy.com
  45. 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 www.indiandentalacademy.com
  46. 46. www.indiandentalacademy.com
  47. 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 www.indiandentalacademy.com
  48. 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. www.indiandentalacademy.com
  49. 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 www.indiandentalacademy.com
  50. 50. Gallium alloy► Alloy: Liquid:Silver60%Tin 25% Gallium 62%copper 13% Iridium 25%Palladium 20% Tin 25% www.indiandentalacademy.com
  51. 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. www.indiandentalacademy.com
  52. 52. www.indiandentalacademy.com
  53. 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 www.indiandentalacademy.com
  54. 54. Manipulation1. Choice of alloy and mercury2. Proportioning3. Trituration4. Mulling5. Condensation6. Burnishing7. Carving8. Finishing and polishing www.indiandentalacademy.com
  55. 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: www.indiandentalacademy.com
  56. 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 www.indiandentalacademy.com
  57. 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 www.indiandentalacademy.com
  58. 58. www.indiand
  59. 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 www.indiandentalacademy.com
  60. 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 www.indiandentalacademy.com
  61. 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 www.indiandentalacademy.com
  62. 62. www.indiandentalacademy.com
  63. 63. www.indiandentalacademy.com
  64. 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 www.indiandentalacademy.com
  65. 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 www.indiandentalacademy.com
  66. 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 www.indiandentalacademy.com
  67. 67. www.indiandentalacademy.com
  68. 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 www.indiandentalacademy.com
  69. 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 www.indiandentalacademy.com
  70. 70. www.indiandentalacademy.com
  71. 71. Types of condensors► Shapes:1. Round2. Parallelogram3. Diamond4. EllipticalVarious contours:1. Flat2. Concave3. angular www.indiandentalacademy.com
  72. 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 www.indiandentalacademy.com
  73. 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 www.indiandentalacademy.com
  74. 74. www.indiandentalacademy.com
  75. 75. ► Sweeney’s instrumentshas sharp angles condensing amalgam into angles www.indiandentalacademy.com
  76. 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. www.indiandentalacademy.com
  77. 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. www.indiandentalacademy.com
  78. 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 www.indiandentalacademy.com
  79. 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 www.indiandentalacademy.com
  80. 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 www.indiandentalacademy.com
  81. 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 www.indiandentalacademy.com
  82. 82. www.indiand
  83. 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 www.indiandentalacademy.com
  84. 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 www.indiandentalacademy.com
  85. 85. www.indiand
  86. 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 www.indiandentalacademy.com
  87. 87. www.indiand
  88. 88. www.indiand
  89. 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 www.indiandentalacademy.com
  90. 90. objectives1. Conversion of superficial amalgam into relatively inert layer galvanically2. Removal of superficial scratches and irregularities3. Minimises concentration cell corrosion www.indiandentalacademy.com
  91. 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 www.indiandentalacademy.com
  92. 92. www.indiandentalacademy.com
  93. 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 www.indiandentalacademy.com
  94. 94. Reasons for failures► Defective cavity preparation: 56% of failures► Defective manipulation: 42% failures► Defective matrix adaptation► Defective materials www.indiandentalacademy.com
  95. 95. Marginal failures www.indiandentalacademy.com
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  97. 97. www.indiandentalacademy.com
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  100. 100. www.indiandentalacademy.com
  101. 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 www.indiandentalacademy.com
  102. 102. Defective amalgam manipulation► Improper condensation► Incorrect mercury alloy ratio► Contamination► Defective finishing and polishing www.indiandentalacademy.com
  103. 103. Post operative pain► High points► Delayed expansion► Inadequate pulp protection► Continuous leakage around filling www.indiandentalacademy.com
  104. 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 www.indiandentalacademy.com
  105. 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, www.indiandentalacademy.com
  106. 106. Bonding interface► Tag formation► Chemical binding to the inorganic or org components of dentin► Formation of hybrid layer of reinforced dentin www.indiandentalacademy.com
  107. 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 www.indiandentalacademy.com
  108. 108. Limitations► Technique sensitive► Bond strength is reduced after some years► Cost of bonded amalgam is more than nonbonded www.indiandentalacademy.com
  109. 109. Gallium alloy► Alloy: Liquid:Silver60%Tin 25% Gallium 62%copper 13% Iridium 25%Palladium 20% Tin 25% www.indiandentalacademy.com
  110. 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. www.indiandentalacademy.com
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  112. 112. conclusion www.indiandentalacademy.com
  113. 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 www.indiandentalacademy.com
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  115. 115. www.indiandentalacademy.com
  116. 116. Thank you www.indiandentalacademy.com

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