Abrasives finals

Arkansas Stone

A semi-translucent light-gray siliceous sedimentary rock mined in Arkansas, contains microcrystalline quartz and is dense, hard, and uniformly textured.

Arkansas Stone

Used for fine grinding of tooth enamel and metal alloys.

Chalk

One of the mineral forms of calcite, a white abrasive composed of calcium carbonate.

Chalk

Used as a mild abrasive paste to polish tooth enamel, gold foil, amalgam, and plastic materials.

Cuttle

Cuttlebone is a white calcareous powder made from the pulverized internal shell of a Mediterranean marine mollusk of the genus Sepia.

Cuttle

Useful for delicate abrasion operations such as the polishing of metal margins and dental amalgam restorations.

Corundum

White mineral form of aluminum oxide.

Corundum

Used primarily for grinding metal alloys and is available as a bonded abrasive in several shapes, most commonly used in an instrument known as white stone.

Natural Diamond

A transparent colorless mineral composed of carbon; the hardest known substance with superabrasive ability to abrade any other known substance.

Natural Diamond

Supplied as bonded abrasive rotary instruments, metal-backed abrasive strips, and diamond polishing pastes.

Natural Diamond

Mostly used on ceramic and resin-based composite materials.

Synthetic Diamond Abrasives

Have consistent size and shape and lower cost. Can be bonded to metal or resins.

Synthetic Diamond Abrasives

Used primarily on tooth structure, ceramic materials, and resin-based composite materials.

Emery

A grayish-black corundum prepared in a fine-grain form, used predominantly in coated abrasive discs and available in a variety of grit sizes.

Emery

Used for finishing metal alloys or acrylic resin materials.

Garnet

Includes different minerals like silicates of aluminum, cobalt, iron, magnesium, and manganese; usually dark red and extremely hard.

Garnet

Available on coated discs and arbor bands.

Garnet

Used in grinding metal alloys and acrylic resin materials.

Kieselguhr

Composed of the siliceous remains of minute aquatic plants known as diatoms.

Kieselguhr

The coarser form is called diatomaceous earth and is used as a filler in many dental materials.

Kieselguhr

An excellent mild abrasive; chronic exposure may produce a risk for silicosis.

Pumice

Produced from volcanic activity, used mainly in grit form, and also found in some rubber-bonded abrasives.

Pumice

Flour of pumice is an extremely fine-grained volcanic rock derivative from Italy.

Pumice

Used in polishing tooth enamel, direct-filling gold, dental amalgam, and acrylic resins.

Quartz

The most commonly used form of silica (SiO₂); a very hard, colorless, transparent, and widespread mineral.

Quartz

Particles are pulverized to form sharp, angular particles useful in making coated abrasive discs.

Quartz

Used primarily to finish metal alloys and may also be used to grind dental enamel.

Sand

A mixture of small mineral particles predominantly composed of silica.

Sand

Particles vary in color and have rounded to angular shapes.

Sand

Applied under air pressure through sandblasting to remove refractory investment materials from base metal alloy castings.

Sand

Also coated onto paper discs for grinding metal alloys and acrylic resin materials.

Tripoli

Derived from lightweight, friable siliceous sedimentary rocks that may be white, gray, pink, red, or yellow.

Tripoli

The gray and red types are most frequently used in dentistry.

Tripoli

Used for polishing metal alloys and some acrylic resin materials.

Rouge

Iron oxide is its fine red abrasive component and is blended with various soft binders into a cake form.

Rouge

Used to polish high noble metal alloys such as yellow gold alloys.

Silicon Carbide

The first synthetic abrasive produced; extremely hard and brittle.

Silicon Carbide

Green and blue-black types are available, with the green form often preferred.

Silicon Carbide

Available as coated discs and as vitreous- and rubber-bonded instruments.

Silicon Carbide

Used for highly efficient cutting of metal alloys, ceramics, and acrylic resin materials.

Tin Oxide

An extremely fine abrasive material.

Tin Oxide

Used extensively as a polishing agent for teeth and metallic restorations such as dental amalgams in the mouth.

Tin Oxide

Mixed with water, alcohol, or glycerin to form a mildly abrasive paste.

Zirconium Silicate

Zircon or zirconium silicate (ZrSiO₄) is supplied as an off-white mineral.

Zirconium Silicate

Ground to various particle sizes and used to make coated abrasive discs and strips.

Zirconium Silicate

Frequently used as a component of dental prophylaxis pastes.

Aluminum oxide and diamond

most popular nonbonded abrasives

○ ceramics

○ metals

○ resin-based composites.

Different abrasives are used for the three major classes of materials:

● tooth cleaning (dental prophylaxis),

● occlusal adjustment of tooth enamel and restoration surfaces,

● contouring of material (acrylic, composite, metal, and ceramic) surfaces,

● finishing and debris removal (grinding and air-particle abrasion), and

● fine polishing to produce glossy surfaces.

Dental abrasives are used for:

● Gingival health

● Chewing efficiency

Also, tarnish and corrosion activity of some metallic restorations can be significantly reduced.

● Patient comfort

● Esthetics

BENEFITS OF FINISHING AND POLISHING RESTORATIVE MATERIALS

Cutting

usually involves the use of a bladed instrument or any other instrument in a bladelike fashion.

Grinding

uses bonded or coated abrasive instruments with randomly arranged abrasive particles.

grinding and cutting

both considered unidirectional in their action

1. diamond burs, abrasive wheels- grinding

2. tungsten carbide burs, steel burs- cutting

Bulk Reduction process can be achieved by:

Contouring

requires finer cutting instruments or abrasives to provide better control of contouring surface details.

Finishing

provides a relatively blemish-free smooth surface.

Polishing

the purpose is provide enamel-like luster to the restoration

coarse

medium coarse

medium, fine

superfine,

Dental abrasive grits are classified as

1. sintering

2. vitreous bonding (glass or ceramic)

3. resinous bonding (usually phenolic resin)

4. rubber bonding (latex-based or silicone-based rubber).

Particles are bonded by four general methods: (BONDED ABRASIVES)

Sintered abrasives

the strongest type because the abrasive particles are fused together.

Vitreous-bonded abrasives

mixed with a glassy or ceramic matrix material, cold pressed to the instrument shape, and fired to fuse the binder

Resin-bonded abrasives

cold-pressed or hot-pressed and then heated to cure the resin.

Coated abrasives

are fabricated by securing abrasive particles to a flexible backing material with a suitable adhesive material

Nonbonded Abrasives

are polishing pastes, dispersed in a water-soluble medium such as glycerin and applied to the substrate with a non abrasive devise such as synthetic foam, rubber, felt, or chamois cloth.

synthetic foam

rubber, felt

chamois cloth.

non abrasive devise such as

○ rotary

○ planar

○ reciprocal

The motion of abrasive instruments is classified as