Abrasive and Polishing Materials

Cutting and Grinding

Involve the removal of larger amounts of material through the action of blades or abrasive particles that generate sufficient tensile and shear stresses to fracture and detach substrate particles (2).

Finishing

Refines these surfaces by using progressively finer abrasives to eliminate deep scratches and create a uniform texture.

Polishing

Completes the sequence by producing a smooth, glossy surface with microscopic scratch patterns that enhance aesthetics, reduce plaque accumulation, and improve material longevity.

Bulk-Reduction Process

Is performed using instruments such as: diamond burs, tungsten carbide burs, steel burs, abrasive wheels, separating discs, and abrasive-coated discs.

Carbide

For resin-based composites, use 8–12 fluted _______ burs or abrasives ≥100 µm, Mohs hardness 9-10.

Diamonds - Flutes

For resin-based composites, coarse ________ / low _____ create faster cut, rougher surface.

Carbide

For resin-based composites, higher fluted _______ burs creates a smoother finish.

Contouring

May begin during bulk reduction but often requires finer cutting instruments or abrasives to achieve better control of anatomy and surface details.

Finishing

_________ produces a relatively smooth, blemish-free surface and is typically performed with: 18- to 30-fluted carbide burs, fine or superfine diamond burs, or abrasives ranging from 8 to 20 µm.

20

Polishing uses very fine abrasives, ideally ≤__ µm, to produce an enamel-like luster, with each step followed by cleaning to prevent deep scratches.

Profilometry - Microscopy

The quality of the polish can be assessed using ____________ or __________, although in clinical practice luster is judged visually.

Porous

Tools such as rubber points, fine discs, strips, and polishing pastes applied with _______ applicators are used.

Yes

Is polishing multidirectional and heat-sensitive?

Finishing

Dispersions of solid particles are generated and released into the breathing space during _________ operations, and these particles may contain tooth structure, dental materials, and microorganisms.

Silicosis

Also called grinder’s disease and is caused by inhalation of aerosol particles from silica based materials used in processing and finishing of dental restorations.

Silicosis

It is a fibrotic pulmonary disease that severely debilitates the lungs and doubles the risk for lung cancer.

95%

About __% of generated aerosol particles are smaller than 5 µm in diameter, allowing them to reach the pulmonary alveoli during normal respiration.

Wear

Is a material removal process that occurs when surfaces slide against each other.

Abrasive - Substrate

The outermost particles or surface material of an abrading instrument are the ________, while the material being finished is the _________.

Opposite

Translating the handpiece and bur ________ to the rotational direction produces a smoother grinding action.

Two-body

___-____abrasion occurs when abrasive particles are firmly bonded to the surface of the abrasive instrument, such as a diamond bur abrading a tooth.

Three-body

_____-____ abrasion occurs when abrasive particles are free to translate and rotate between two surfaces, such as nonbonded abrasives in dental prophylaxis pastes.

Lubricants

Used to minimize unintentional shifts between two-body and three-body wear; they improve the efficiency of cutting and grinding.

Water

Examples of lubricants include water, glycerin, and silicone, with a _____-soluble lubricant preferred intraorally.

Erosive

_______ wear is caused by hard particles impacting a substrate surface, carried by a stream of liquid or a stream of air, as in sandblasting.

Chemical

________ erosion uses chemicals such as acids and alkalis to remove substrate material, unlike hard particles.

Acid Etching

Chemical erosion, commonly called ____ _______, is not used for finishing dental materials but is used to prepare tooth surfaces to enhance bonding or coating.

Knoop and Vickers

These tests use indentation methods, applying a diamond indenter under a known load, usually 100 Newtons.

Efficient

The farther apart a substrate and an abrasive are in hardness, the more _________ the abrasion process.

Abrasive Grits

Derived from materials that have been crushed and passed through a series of mesh screens (sieves) to obtain different particle size ranges.

Bonded Abrasives

Abrasive particles incorporated through a binder to form grinding tools such as points, wheels, separating discs, coated thin discs, etc.

Sintering - Vitreous Bonding - Resinous Bonding - Rubber Bonding

What are the 4 bonding methods?

Sintering

(Method) These abrasives are the strongest type because the abrasive particles are fused together.

Vitreous Bonding

(Method) These abrasives are mixed with a glassy or ceramic matrix material, cold-pressed to the instrument shape, and fired to fuse the binder.

Resinous Bonding

(Method) Abrasives are cold pressed or hot-pressed and then heated to cure the resin.

Rubber Bonding

(Method) These abrasives are made in a manner similar to that for resin-bonded abrasives

Aluminum Oxide Abrasive

Most types of discs are coated with?

Metal Strips

(Strips) Usually limited to situations in which very tight proximal contacts are involved. Useful for ceramic restorations but are also used for resin composites and amalgams.

Metal-backed Strips

(Strips) More costly, but can be autoclaved and used several times if not damaged.

Plastic-backed Strips

(Strips) Used primarily for resin composites, compomers, hybrid ionomers, and resin cements.

Truing

Procedure by which the abrasive instrument is run against a harder abrasive block until the abrasive instrument rotates in the handpiece without eccentricity or runout when placed on the substrate.

Dressing

Reduces the instrument to its correct working size and shape and is used to remove clogged debris from the abrasive instrument to restore grinding efficiency.

Diamond

Binders for _______ abrasives are manufactured specifically to resist abrasive particle loss rather than to degrade at a certain point and release particles.

Metal Wheels - Bur Blanks

Diamond particles are bonded to _____ _______ and ___ _______ with special heat resistant resins such as polyimides.

Coated Abrasives

Fabricated by securing abrasive particles to a flexible backing material (heavyweight paper, metal, or Mylar) with a suitable adhesive material.

Nonbonded

Polishing pastes are considered _________ abrasives and are primarily used for final polishing.

Water

(Nonbonded) Abrasive particles are dispersed in a _____-soluble medium such as glycerin for dental applications.

Aluminum Oxide - Diamond

Most popular nonbonded abrasive materials (2).

Rotary - Planar - Reciprocal

Abrasive motion is classified as (3)?

Manufactured Abrasives

Are synthetically produced abrasives and preferred because of their predictable physical properties.

Aluminum Oxide (Alumina)

Fused _________ _____ was the second synthetic abrasive developed.

Aluminum Oxide (Alumina)

Fused ________ _____ was the second synthetic abrasive developed.

Aluminum Oxide (Alumina)

Pure white powder and can be harder than natural corundum due to greater purity. Replaced emery in many uses.

White Stone (Sintered Alumina)

(Alumina) For adjusting enamel and finishing metal alloys, resin composites, and ceramic materials.

Pink and Ruby Stones

(Alumina) Made by adding chromium compounds; used in preparing metal–ceramic alloys before porcelain application.

Corundum

A mineral form of aluminum oxide. Primarily used in white stones for grinding metal alloys.

Corundum

Usually white in color. Primarily used in white stones for grinding metal alloys.

Emery

Grayish-black corundum prepared in fine-grain form. Used in coated abrasive discs. For finishing metal alloys and acrylics.

Cuttle

Commonly known as cuttlefish, cuttlebone, or cuttle. Available as coated abrasive.

Cuttle

Made from the pulverized internal shell of the Mediterranean marine mollusk of the genus Sepia.

Arkansas Stone

A semi-translucent, light-gray siliceous sedimentary rock. Used for fine grinding of enamel and metal alloys.

Arkansas Stone

A semi-translucent, light-gray siliceous sedimentary rock. Contains microcrystalline quartz and is dense, hard, and uniform texture.

Natural Diamond

Transparent, colorless mineral composed of carbon. Hardest known material. Called as a superabrasive due to its ability to abrade any other substance.

Chalk

A white, soft abrasive form of calcium carbonate. Mild abrasive.

Garnet

A natural dark red mineral that belongs to a group of aluminum silicates.

Kieselguhr (Diatomaceous Earth)

Is made from the fossilized shells of tiny algae called diatoms. It looks like a very fine, soft, white powder. It’s not a strong abrasive—more like a mild, gentle polishing agent.

Pumice

A volcanic glass with many tiny air pockets, making it both abrasive and lightweight. Commonly mixed with water to form a slurry.

Quartz

Crystalline silica; very hard natural abrasive. Previously used for grinding and trimming.

Sand

Dental “____” is mostly silica particles used for sandblasting and air abrasion.

Tripoli

A soft abrasive made from weathered siliceous rock. It has a brownish color and a mild cutting action. It leaves a satin-like, semi-smooth surface, making it perfect before the final polish.

Rouge (Jeweler’s Rouge)

A very fine iron oxide powder, usually red or reddish brown. Creates a mirror-like shine and is used after tripoli for a perfect finish.

Silicon Carbide

A synthetic abrasive that is extremely hard (around Mohs 9), usually black or dark green.

Tin Oxide

A very fine, white polishing powder. Traditionally used for the final polish. Mixed with water or glycerin to form a paste. Produces a glossy, smooth surface without scratching.

Zirconium Silicate

Hard, durable abrasive commonly found in prophy pastes and polishing agents. Offers good abrasive control and is gentle enough for enamel.

Burnishing

(Amalgam) __________ before carving removes excess mercury; and after carving it improves smoothness.

Low Speed

(Amalgam) Is low or high speed handpieces recommended?

Gold

Pure ____ is soft and ductile and requires slow-speed finishing.

Tungsten

(Acrylic) Contour with ________ carbide burs and sandpaper.

Air-Particle Abrasion Technology

Alternative to rotary cutting instruments. Uses a high-pressure stream of 25–30 µm aluminum oxide particles.

Dentifrices

Provide more efficient removal of debris, plaque, and stained pellicle compared with use of a toothbrush alone.

Tartar-Control Agents

Agents such as potassium and sodium pyrophosphates can reduce the rate at which new calculus deposits form supragingivally.