finishing and polishing materials.9

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Finishing and polishingFinishing and polishingmaterialsmaterials

Key terms:Key terms:Finishing:Finishing: Process of removing the excessProcess of removing the excessmaterialsmaterialsPolishing:Polishing: smooth and luster the finishedsmooth and luster the finishedsurfacesurfaceAbrasive:Abrasive: A hard substance used to finishA hard substance used to finish

,grinding or polishing a less hard surface.,grinding or polishing a less hard surface.Substrate :Substrate : is the object to be finished andis the object to be finished andpolished.polished.


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Importance of finishingImportance of finishing&polishing:&polishing:

1-promotes the oral health by resisting1-promotes the oral health by resistingaccumulation of food debrisaccumulation of food debris

2- Enhancing oral functions because foods glides2- Enhancing oral functions because foods glides

more freely over occlusal surfaces duringmore freely over occlusal surfaces duringmasticationmastication

3- Improve strength of the restorations3- Improve strength of the restorations

4-Glazed surface provide a good aesthetic4-Glazed surface provide a good aesthetic

5- easy cleaning the restoration5- easy cleaning the restoration


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Factors affecting rate of abrasionFactors affecting rate of abrasion

11 . Hardness. Hardness ;; most effective grinding occur whenmost effective grinding occur whenthere is large differences in hardness betweenthere is large differences in hardness betweenabrasives and substrate.abrasives and substrate.2. Particle size:2. Particle size: abrasives classified into large,abrasives classified into large,medium &fine particles , so large particle sizemedium &fine particles , so large particle sizeproduce more grinding.produce more grinding.3.Particle shape:3.Particle shape: which may be irregular orwhich may be irregular orregular . The irregular particle size will abraderegular . The irregular particle size will abraderapidly.rapidly.4.Speed and pressure:4.Speed and pressure: The greater the speedThe greater the speedand friction will abrade more rapidlyand friction will abrade more rapidly5. lubricant:5. lubricant: as silicone grease-water spray andas silicone grease-water spray andglycerol will reduce heat generationglycerol will reduce heat generation


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Types of abrasivesTypes of abrasives

1. Finishing abrasives1. Finishing abrasives :: generally hard,generally hard,coarse ,irregular which used to removecoarse ,irregular which used to removeexcess and contouring the restorationsexcess and contouring the restorations2. Polishing abrasives:2. Polishing abrasives: Generally lessGenerally lesshard, fine ,smooth to produce a lusterhard, fine ,smooth to produce a lustersurfacesurface3. Cleansing abrasives3. Cleansing abrasives :: Generally softGenerally softmaterials with small particle size tomaterials with small particle size to

remove a soft material that adhere toremove a soft material that adhere toenamel or restoration.enamel or restoration.Typical abrasive media are alumina,Typical abrasive media are alumina,silicone carbide and chromic oxide.silicone carbide and chromic oxide.


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POLISHING MATERIALSPOLISHING MATERIALSa.Tin Oxide.a.Tin Oxide. Tin oxide is used in polishing teeth and metalTin oxide is used in polishing teeth and metal

restorations. Tin oxide is a fine, white powder that is maderestorations. Tin oxide is a fine, white powder that is madeinto a paste by adding water or glycerin.into a paste by adding water or glycerin.

b. Pumice.b. Pumice. Pumice is used as an abrasive and polishing agent forPumice is used as an abrasive and polishing agent foracrylic resins, amalgams, and gold. It consists mainly of acrylic resins, amalgams, and gold. It consists mainly of complex silicates of aluminum, potassium, and sodium. Twocomplex silicates of aluminum, potassium, and sodium. Twogrades--flour of pumice and coarse pumice--are listed in thegrades--flour of pumice and coarse pumice--are listed in theFederal Supply Catalog.Federal Supply Catalog.

c.c. Chalk (Whiting).Chalk (Whiting). Chalk is used for polishing acrylic resins andChalk is used for polishing acrylic resins andmetals. It is composed primarily of calcium carbonate.metals. It is composed primarily of calcium carbonate.

d. Tripoli.d. Tripoli. Tripoli is usually used for polishing gold and otherTripoli is usually used for polishing gold and othermetals. It is made from certain porous rocks.metals. It is made from certain porous rocks.e. Rouge (Jeweler's). Rouge is used for polishing gold and ise. Rouge (Jeweler's). Rouge is used for polishing gold and is

composed of iron oxide. It is usually in cake or stick form.composed of iron oxide. It is usually in cake or stick form.f. Zirconium Silicate.f. Zirconium Silicate. Zirconium silicate is used for cleaning andZirconium silicate is used for cleaning and

polishing teeth. It may be mixed with water or with fluoridepolishing teeth. It may be mixed with water or with fluoridesolution for caries prevention treatment. For fullsolution for caries prevention treatment. For full

effectiveness, instructions must be followed exactly to obtaineffectiveness, instructions must be followed exactly to obtainthe proper proportions of powder to liquid.the proper proportions of powder to liquid.


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c. Disadvantages.c. Disadvantages. (1) They shrink when used with a solvent.(1) They shrink when used with a solvent.(2) They are not always easy to introduce into the root(2) They are not always easy to introduce into the root

canal.canal.

SILVER ROOT CANAL POINTSSILVER ROOT CANAL POINTS

a. Advantagesa. Advantages . The dental officer has the option to use. The dental officer has the option to usesilver root canal points in filling a root canal.silver root canal points in filling a root canal.(1) They are more easily inserted than gutta-percha(1) They are more easily inserted than gutta-percha

points and they have all the same advantages.points and they have all the same advantages.(2) Sight selection of silver points is easy because they(2) Sight selection of silver points is easy because they

come in the same sizes and tapers as standard rootcome in the same sizes and tapers as standard rootcanal broaches and reamers.canal broaches and reamers.b. Disadvantages.b. Disadvantages. (1) They are more expensive than gutta-percha.(1) They are more expensive than gutta-percha.(2) They do not adapt to contours of the root canal.(2) They do not adapt to contours of the root canal.(3) They tend to corrode if subjected to body fluids.(3) They tend to corrode if subjected to body fluids.

finishing and polishing materials.9

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