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Abrasives 
Presented By : Arpit Viradiya Guided By : Dr Sandeep Metgud 
Dr Deepali Agrawal
Contents 
• Definition 
• Abrasive action 
• Types of abrasion 
• Principles : Cutting Grinding & Polishing 
• Desirable C...
• Craig has defined abrasion as: 
• "A process of wear whereby a hard rough 
surface (like a sand paper disk) or hard 
irr...
Abrasive action 
Harder material comes into frictional contact with 
the substrate 
Contact generates tensile and shear st...
Types of abrasion 
1. Two-body abrasion 
• Abrasive bonded to instrument 
Eg - diamond bur abrading a tooth.
Three-body abrasion 
• Non bonded abrasives 
• Abrasive particles are free 
Eg - dental prophylaxis paste
Erosion 
• Wear caused by hard particles impacting a 
substrate surface, carried by a stream of 
liquid or stream of air. ...
Principles 
Cutting 
• Use of any instrument in a bladelike fashion 
• Regularly arranged blades that remove small 
shavin...
Grinding 
• Removes small particles of a substrate 
through the action of bonded or coated 
abrasive instruments 
• Predom...
Polishing 
• Most refined of the finishing processes 
• Multidirectional in its course of action 
• Acts on an extremely t...
Desirable Characteristics Of An 
Abrasive 
• It should be irregular in shape so that it 
presents a sharp edge. 
• It shou...
Factors affecting abrasion 
• Hardness 
• Shape 
• Size 
• Pressure 
• Speed 
• lubricants
Factors affecting rate of abrasion 
Hardness 
• Relates to durability of an abrasive 
• Measure of a material’s ability to...
Material Moh’s Brinell Knoop Material Moh’s Brinell Knoop 
Talc 1 Alumnium oxide 9 1700 1900 
Gypsum 2 Silicon carbide 9-1...
Shape 
• Sharp, irregular particle produces deeper abrasion than 
rounder particle under equal applied force 
• Numerous s...
Size 
• Larger particles size, abrade a surface more rapidly 
• Particles based on their size: 
1. Coarse -53 μm to 142 μm...
Pressure 
Greater force during finishing 
Abrasive cut deeper into the surface 
More rapid removal of material 
Raise in t...
• Deeper and wider scratches are produced by increasing 
the applied force from F1and F2
Speed 
Faster speed 
Faster cutting rates 
Temperature increases 
Greater danger of overcutting
Lubrication 
• Minimize the heat buildup 
• Facilitates removal of debris 
• Cooling action and removal of debris enhances...
Abrasive Instrument Design 
• Abrasive Grits. 
• Bonded Abrasives. 
• Coated abrasive disks and strips 
• Non bonded abras...
Abrasive grits 
• Derived from materials that have been 
crushed and passed through a series of 
mesh screens 
• Dental ab...
Bonded abrasives 
• Abrasive particles are incorporated through 
a binder to form grinding tool 
• Particles are bonded by...
Type of bonding and grinding behaviour 
1. Bonded abrasives that tend to disintegrate 
rapidly against substrate are weak ...
Maintenance of the efficiency of abrasive 
• Truing : abrasive instrument is run against a 
harder abrasive block until th...
• Dressing : 
1)Reduces instrument to correct working 
size, shape 
2)Removes clogged debris (abrasive 
blinding) - Restor...
Coated Abrasive Disks and Strips 
• supplied as disks and finishing strips. 
• Fabricated by securing abrasive particles t...
Abrasive discs : 
• Gross reduction, contouring, finishing, and 
polishing of restoration surfaces 
• Coated with aluminum...
Non bonded abrasives 
• Polishing pastes - final polishing. 
• Applied to substrate with a nonabrasive 
device - synthetic...
Classification : 
Natural abrasives 
1. Arkansas Stone 
2. Chalk 
3.Corundum 
4.Diamond 
5.Emery 
6.Garnet 
7. Pumice 
8. ...
Synthetic Abrasives 
1.Silicon carbide 
2.Aluminium oxide 
3.Synthetic diamond 
4.Rouge 
5.Tin oxide
Arkansas stone 
• Semi translucent , light gray, siliceous 
sedimentary rock. 
• Contains microcrystalline quartz. 
• Atta...
Chalk 
• Mineral forms of calcite. 
• White abrasive composed of 
calcium carbonate. 
• Used as a mild abrasive paste to 
...
Natural Diamond 
• Transparent colorless mineral 
composed of carbon 
• Superabrasive 
• Supplied in several forms 
• Bond...
Diamond abrasive instruments 
Introduced in the united states in 1942. 
Consists of 3 parts : 
metal blank 
powdered diamo...
Various Shapes of Diamond abrasive instruments
Diamond particle factors 
Particle size is categorized as: 
Coarse (125-150 um) 
medium (88-125 um) 
Fine (60-74 um) 
Very...
Corundum 
• Mineral form of aluminum 
oxide 
• Physical properties are inferior 
to those of alpha aluminum 
oxide. 
• Gri...
Emery 
• Natural form of an oxide of aluminium 
• Grayish- black corundum 
• Coated abrasive disks 
• Finishing metal allo...
Garnet 
• Dark red, very hard . 
• Comprise - silicates of Al, Co, 
Mg, Fe, Mn 
• Garnet is coated on paper or 
cloth with...
Pumice 
• Highly siliceous material of 
volcanic origin 
• Powder-crushing pumice stone 
• Abrasive action is not very hig...
Quartz 
• Very hard, colorless, and 
transparent. 
• Crystalline particles are 
pulverized to form sharp, 
angular particl...
Sand 
• Predominantly composed of silica. 
• Particles represent a mixture of color. 
Making it distinct in appearance. 
•...
Tripoli 
• Derived from light weight, friable siliceous sedimentary 
rock. 
• Rock is ground and made into bars with soft ...
Zirconium silicate / Zircon 
• Off -white mineral. 
• Ground to various particle sizes - coated 
abrasive disks and strips...
Cuttle 
• Referred to as cuttle fish, cuttle bone, or cuttle. 
• White calcareous powder 
• Available as a coated abrasive...
Kieselguhr 
• Siliceous remains of minute aquatic plants - 
diatoms. 
• Coarser form - diatomaceous earth 
• Excellent mil...
Synthetic Silicon Carbide 
• Extremely hard abrasive and 1st synthetic abrasive 
• Highly effective cutting of metal alloy...
Aluminum oxide 
• White powder 
• used as bonded abrasives, coated abrasives and air 
propelled abrasives. 
• Finishing me...
Rouge 
• Consists of iron oxide, which is the fine red 
abrasive component. 
• Blended in to various soft binders in to a ...
Tin Oxide 
• Extremely fine abrasive. 
• Less abrasive than quartz. 
• Polishing teeth and metallic 
restorations in the m...
Synthetic Diamond 
• Controllable, consistent size and shape. 
• Resin bonded diamonds have sharp edges 
• Larger syntheti...
Dentifrices 
• Available as toothpaste, gels and powders. 
• The abrasive concentrations in paste and gel 
dentrifices are...
Prophylaxis pastes 
• removal of exogenous stains, pellicle, material 
alba, and oral debris. 
• contain moderately abrasi...
Precautions 
• Heat generation during cutting and 
contouring , finishing and polishing 
procedures is a major concern. 
•...
Biological hazards 
• Aerosols – silica based materials (smaller 
than 5μm) 
• Silicosis or grinders disease 
• Precaution...
Recent Advances
Air abrasive Technology 
• Alternative to rotary instrument 
cutting. 
• High pressure stream of 25- 
30μm Al2O3. 
• ‘Air ...
Uses 
• Cavity preparation 
• Removal of defective restorations 
• Endodontic access through porcelain crowns 
• Minimal p...
CVD diamond-coated burs 
• Advantages such as less noise, less pain for 
the patient, precise cutting, conservative 
cavit...
Gripped diamond Strips 
Diamond-coated stainless steel metal strips 
Features: 
used for smoothing, contouring, finishing ...
Finishing and Polishing 
system 
designed to finish and polish all 
types of resin restoratives By 
incorporating a superi...
Perforated Diamond Strips 
Designed for complete control during inter-proximal 
reduction, shaping, and contouring. 
The d...
single-gel diamond 
polishing system 
it can polish the surface of all 
restorative materials: composite, 
glass ionomer, ...
SUMMARY & CONCLUSION 
• Though a varied range of abrasive and 
polishing agents have been described with 
relation to indi...
References 
• Sturdevant’s Art and Science of Operative 
Dentistry, 5th edition, Elsevier publications. 
• Anusavice, Phil...
Thank You
Abrasive agents in dentistry
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Abrasive agents in dentistry

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Dental Abrasives

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Abrasive agents in dentistry

  1. 1. Abrasives Presented By : Arpit Viradiya Guided By : Dr Sandeep Metgud Dr Deepali Agrawal
  2. 2. Contents • Definition • Abrasive action • Types of abrasion • Principles : Cutting Grinding & Polishing • Desirable Characteristics Of An Abrasive • Factors affecting rate of abrasion • Abrasive instrument design • Classification of abrasive agents • Precautions • Biological hazards of abrasive agents • Recent Advances • Summary & Conclusion
  3. 3. • Craig has defined abrasion as: • "A process of wear whereby a hard rough surface (like a sand paper disk) or hard irregular shaped practicles (like those in an abrasive slurry) plough grooves in a softer material and cause materials from these grooves to be removed from the surface".
  4. 4. Abrasive action Harder material comes into frictional contact with the substrate Contact generates tensile and shear stresses Break atomic bonds Substrate particles are removed
  5. 5. Types of abrasion 1. Two-body abrasion • Abrasive bonded to instrument Eg - diamond bur abrading a tooth.
  6. 6. Three-body abrasion • Non bonded abrasives • Abrasive particles are free Eg - dental prophylaxis paste
  7. 7. Erosion • Wear caused by hard particles impacting a substrate surface, carried by a stream of liquid or stream of air. Eg. Sand blasting a surface • Chemical erosion Acid etching Enhance bonding
  8. 8. Principles Cutting • Use of any instrument in a bladelike fashion • Regularly arranged blades that remove small shavings of the substrate • Unidirectional cutting pattern
  9. 9. Grinding • Removes small particles of a substrate through the action of bonded or coated abrasive instruments • Predominantly unidirectional • Innumerable unidirectional scratches • Eg: a diamond coated rotary instrument
  10. 10. Polishing • Most refined of the finishing processes • Multidirectional in its course of action • Acts on an extremely thin region of the substrate surface • Progress - fine polishing media • Final stage produces fine scratches - not visible unless greatly magnified
  11. 11. Desirable Characteristics Of An Abrasive • It should be irregular in shape so that it presents a sharp edge. • It should be harder than the surface it abrades. • Abrasive point should always fracture rather than dull out so that always a sharp point or edge is available. • Abrasive should possess attrition resistance so that it does not wear.
  12. 12. Factors affecting abrasion • Hardness • Shape • Size • Pressure • Speed • lubricants
  13. 13. Factors affecting rate of abrasion Hardness • Relates to durability of an abrasive • Measure of a material’s ability to resist indentation • Abrasive particle must be harder than the surface to be abraded • First ranking of hardness was published in 1820 by Friedrich Mohs • Knoop and Vickers hardness tests
  14. 14. Material Moh’s Brinell Knoop Material Moh’s Brinell Knoop Talc 1 Alumnium oxide 9 1700 1900 Gypsum 2 Silicon carbide 9-10 3000 2500 Chalk 3 Boron carbide 9-10 2800 Rouge 5-6 Diamond 10 >3000 7000 Pumice 6 450 560 SUBSTRATES Tripoli 6-7 Acrylic 2-3 25 Garnet 6.5-7 550 Pure gold 2.5-3 30 Tin oxide 6-7 Porcelain 6-7 400 Sand 7 650 800 Amalgam 4-5 90 Cuttle 7 650 800 Dentin 3-4 Tool steel 800 Enamel 5-6 270 Zirconium 7-7.5 Glass 5-6 silicate Tungsten carbide 9 1200 2100 Resin composite 5-7 200
  15. 15. Shape • Sharp, irregular particle produces deeper abrasion than rounder particle under equal applied force • Numerous sharp edges - enhanced cutting efficiency • Abrasion rate of an abrasive decreases with use
  16. 16. Size • Larger particles size, abrade a surface more rapidly • Particles based on their size: 1. Coarse -53 μm to 142 μm, 2. Medium -15 μm to 52 μm, 3. Fine - 7 to 14 μm. 4. Superfine – 2 to 6 um.
  17. 17. Pressure Greater force during finishing Abrasive cut deeper into the surface More rapid removal of material Raise in temperature within the substrate Distortion or physical changes within the substrate
  18. 18. • Deeper and wider scratches are produced by increasing the applied force from F1and F2
  19. 19. Speed Faster speed Faster cutting rates Temperature increases Greater danger of overcutting
  20. 20. Lubrication • Minimize the heat buildup • Facilitates removal of debris • Cooling action and removal of debris enhances the abrasion process. • Water is the most common lubricant • Eg. Water, glycerin or silicone • Excess lubrication – prevent abrasive contact
  21. 21. Abrasive Instrument Design • Abrasive Grits. • Bonded Abrasives. • Coated abrasive disks and strips • Non bonded abrasives
  22. 22. Abrasive grits • Derived from materials that have been crushed and passed through a series of mesh screens • Dental abrasive grits based on particle size are • Coarse • Medium coarse • Medium • Fine • Superfine
  23. 23. Bonded abrasives • Abrasive particles are incorporated through a binder to form grinding tool • Particles are bonded by four general methods: • Sintering • Vitreous bonding • Resinous bonding • Rubber bonding (latex or silicon based)
  24. 24. Type of bonding and grinding behaviour 1. Bonded abrasives that tend to disintegrate rapidly against substrate are weak • Increased abrasive cost - Reduced instrument life 2. Abrasives that tend to degrade too slowly clog with grinding debris • Loss of abrasive efficiency, increased heat generation, and increased finishing time
  25. 25. Maintenance of the efficiency of abrasive • Truing : abrasive instrument is run against a harder abrasive block until the abrasive instrument rotates in the hand piece without eccentricity or runout when placed on a substrate.
  26. 26. • Dressing : 1)Reduces instrument to correct working size, shape 2)Removes clogged debris (abrasive blinding) - Restores grinding efficiency Truing
  27. 27. Coated Abrasive Disks and Strips • supplied as disks and finishing strips. • Fabricated by securing abrasive particles to a flexible backing material • available in different diameters with thin and very thin backings. • Moisture – resistant backings are advantageous
  28. 28. Abrasive discs : • Gross reduction, contouring, finishing, and polishing of restoration surfaces • Coated with aluminum oxide abrasive Abrasive strips : • With plastic or metal backing are available for smoothening and polishing the interproximal surfaces of direct and indirect bonded restorations
  29. 29. Non bonded abrasives • Polishing pastes - final polishing. • Applied to substrate with a nonabrasive device - synthetic foam , rubber, felt, or chamois cloth. • Dispersed in water soluble medium such as glycerin for dental applications. • Aluminium oxide and diamond
  30. 30. Classification : Natural abrasives 1. Arkansas Stone 2. Chalk 3.Corundum 4.Diamond 5.Emery 6.Garnet 7. Pumice 8. Quartz 9. Sand 10. Tripoli 11. Zirconium silicate 12. Cuttle 13. Kieselguhr
  31. 31. Synthetic Abrasives 1.Silicon carbide 2.Aluminium oxide 3.Synthetic diamond 4.Rouge 5.Tin oxide
  32. 32. Arkansas stone • Semi translucent , light gray, siliceous sedimentary rock. • Contains microcrystalline quartz. • Attached to metal shanks and trued to various shapes • Fine grinding of tooth enamel and metal alloys
  33. 33. Chalk • Mineral forms of calcite. • White abrasive composed of calcium carbonate. • Used as a mild abrasive paste to polish tooth enamel, gold foil, amalgam and plastic materials.
  34. 34. Natural Diamond • Transparent colorless mineral composed of carbon • Superabrasive • Supplied in several forms • Bonded abrasive rotary instruments • Flexible metal backed abrasive strips • Diamond polishing pastes. • Used on tooth structure; ceramic and resin based composite materials
  35. 35. Diamond abrasive instruments Introduced in the united states in 1942. Consists of 3 parts : metal blank powdered diamond abrasive metallic bonding material. •Blank resembles a bur without blades. •The diamonds are attached to the blank by electroplating a layer of metal on the blank while holding the diamonds in place against it. •Diamond instruments are available in variety of sizes & shapes. •More than 200 shapes & sizes are available. •Lack of uniform nomenclature for diamond instruments.
  36. 36. Various Shapes of Diamond abrasive instruments
  37. 37. Diamond particle factors Particle size is categorized as: Coarse (125-150 um) medium (88-125 um) Fine (60-74 um) Very fine (38-44 um) Diamond finishing instruments use even finer diamonds (10-38 um) Only cause of failure of diamond instruments is loss of diamonds from critical areas which results from the use of excess pressure in attempt to increase the cutting rate.
  38. 38. Corundum • Mineral form of aluminum oxide • Physical properties are inferior to those of alpha aluminum oxide. • Grinding metal alloys • A bonded abrasive in several shapes. • Used in instrument – White stone
  39. 39. Emery • Natural form of an oxide of aluminium • Grayish- black corundum • Coated abrasive disks • Finishing metal alloys or acrylic resin materials.
  40. 40. Garnet • Dark red, very hard . • Comprise - silicates of Al, Co, Mg, Fe, Mn • Garnet is coated on paper or cloth with glue. • Fractured during grinding  sharp, chisel-shaped plates • Grinding metal alloys or acrylic resin materials.
  41. 41. Pumice • Highly siliceous material of volcanic origin • Powder-crushing pumice stone • Abrasive action is not very high • Polishing tooth enamel, gold foil, dental amalgam and acrylic resins
  42. 42. Quartz • Very hard, colorless, and transparent. • Crystalline particles are pulverized to form sharp, angular particles - coated abrasive discs. • Grinding tooth enamel and finishing metal alloys.
  43. 43. Sand • Predominantly composed of silica. • Particles represent a mixture of color. Making it distinct in appearance. • Rounded to angular shape. • Applied under air pressure to remove refractory investment materials • Coated on to paper disks
  44. 44. Tripoli • Derived from light weight, friable siliceous sedimentary rock. • Rock is ground and made into bars with soft binders • Color- white/grey/pink/red/yellow. • Grey and red types • Polishing for metal alloys and some acrylic resins.
  45. 45. Zirconium silicate / Zircon • Off -white mineral. • Ground to various particle sizes - coated abrasive disks and strips. • Component of dental prophylaxis pastes
  46. 46. Cuttle • Referred to as cuttle fish, cuttle bone, or cuttle. • White calcareous powder • Available as a coated abrasive • Polishing of metal margins and amalgam restorations.
  47. 47. Kieselguhr • Siliceous remains of minute aquatic plants - diatoms. • Coarser form - diatomaceous earth • Excellent mild abrasive • Risk for respiratory silicosis caused by chronic exposure
  48. 48. Synthetic Silicon Carbide • Extremely hard abrasive and 1st synthetic abrasive • Highly effective cutting of metal alloys, ceramics and acrylic resin materials. • Abrasive in coated disks and as vitreous - bonded and rubber instruments.
  49. 49. Aluminum oxide • White powder • used as bonded abrasives, coated abrasives and air propelled abrasives. • Finishing metal alloys, resin based composites and ceramic materials. • Pink and ruby variations- adding chromium compounds
  50. 50. Rouge • Consists of iron oxide, which is the fine red abrasive component. • Blended in to various soft binders in to a cake form. • Used to polish high noble metal alloys.
  51. 51. Tin Oxide • Extremely fine abrasive. • Less abrasive than quartz. • Polishing teeth and metallic restorations in the mouth. • Produces excellent polish of enamel. • Mixed with water or glycerin - abrasive paste.
  52. 52. Synthetic Diamond • Controllable, consistent size and shape. • Resin bonded diamonds have sharp edges • Larger synthetic diamond particles – greenish • Blocks with embedded diamond particles – truing other bonded abrasives • Used primarily on tooth structure, ceramics and resin based composites.
  53. 53. Dentifrices • Available as toothpaste, gels and powders. • The abrasive concentrations in paste and gel dentrifices are 50% to 75% lower than those of powder dentrifices • Function : • Abrasive and detergent action • Polish teeth • Act as vehicles
  54. 54. Prophylaxis pastes • removal of exogenous stains, pellicle, material alba, and oral debris. • contain moderately abrasive materials : pumice • Silcon dioxide and zirconium silicate are used • Applied to teeth through rubber cup on a slow speed handpiece
  55. 55. Precautions • Heat generation during cutting and contouring , finishing and polishing procedures is a major concern. • To avoid adverse effects to the pulp, cool the surface using air water spray and intermittent contact.
  56. 56. Biological hazards • Aerosols – silica based materials (smaller than 5μm) • Silicosis or grinders disease • Precautions -adequate water spray, suction -eyeware ,facemasks -proper ventilation
  57. 57. Recent Advances
  58. 58. Air abrasive Technology • Alternative to rotary instrument cutting. • High pressure stream of 25- 30μm Al2O3. • ‘Air polishing’- controlled delivery of air, water and Sodium bicarbonate slurry.
  59. 59. Uses • Cavity preparation • Removal of defective restorations • Endodontic access through porcelain crowns • Minimal preparation to repair crown margins • Superficial removal of stains • Roughening of internal surfaces of indirect porcelains or composite restorations
  60. 60. CVD diamond-coated burs • Advantages such as less noise, less pain for the patient, precise cutting, conservative cavity, preparation, longer lifetime, less injury to the dental structures, no cutting of soft tissues and easier access of the carious lesion.
  61. 61. Gripped diamond Strips Diamond-coated stainless steel metal strips Features: used for smoothing, contouring, finishing and trimming proximal, incisal and interproximal areas two, color-coded working areas with different grit sizes handles help to pull through tight contact areas
  62. 62. Finishing and Polishing system designed to finish and polish all types of resin restoratives By incorporating a superior abrasive into a special resin. System uses a one-piece disc and mandrel - with no metal boss. So that, the possibility of discolouring the restoration has been completely eliminated. It completes intermediate and final finishing without the need to change discs.
  63. 63. Perforated Diamond Strips Designed for complete control during inter-proximal reduction, shaping, and contouring. The design assists in debris removal, provides improved visibility, control, and flexibility; made of stainless steel to resist breaking and stretching. They are color coded for grit identification: blue for medium, red for fine and yellow for super-fine.
  64. 64. single-gel diamond polishing system it can polish the surface of all restorative materials: composite, glass ionomer, compomer, amalgam, precious metal and enamel. Even porcelain achieves a lustrous surface in less time due to the optimal concentration of micron-sized diamond particles.
  65. 65. SUMMARY & CONCLUSION • Though a varied range of abrasive and polishing agents have been described with relation to individual dental materials, an ideal abrasive or a polishing agent which would satisfy all polishing needs of the dental materials, one would say is yet to be developed.
  66. 66. References • Sturdevant’s Art and Science of Operative Dentistry, 5th edition, Elsevier publications. • Anusavice, Phillips Science of Dental Materials, 12th edition, Elsevier publications. • Craig . Powers and Wataha, Dental Materials, Properties and manipulation, 8th edition, Elsevier publications. • Contemporary fixed prosthodontics. 2nd Edition, Stephen F. Rosensteil.
  67. 67. Thank You

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