Dental Materials: Abrasion, Finishing, and Polishing

These flashcards cover key concepts from dental materials focusing on abrasion, finishing, and polishing as discussed in the lecture notes.

Why is proper finishing and polishing of restorations clinically relevant?

It improves esthetics, improves tissue health, and increases the longevity of the restorative material.

What is the difference between finishing, polishing, and cleaning?

Finishing is done immediately after placing a restoration, changing its shape. Polishing changes only the surface texture. Cleaning refers to removing soft biofilm without abrasion.

What is the correct order to use abrasives during finishing or polishing?

Fine to coarse or coarse to fine.

What does the Moh scale rank materials by?

The Moh scale ranks materials by their relative abrasion resistance (hardness).

Why would a patient with porcelain crowns have increased wear on their mandibular anterior teeth?

Porcelain has a Moh ranking of 6-7, which is harder than enamel at 5.5-6, causing wear over time.

What does grit refer to in dental procedures?

Grit refers to the size of the abrasive particles.

What happens to the abrasiveness of particles when lubricant is added?

Abrasiveness is reduced.

What are the negatives of high speed and heavy pressure when using a rotary instrument?

Deeper scratches, decreased control of material removal, decreased tactile sensitivity, decreased cutting efficiency, and increased frictional heat that may aggravate the pulp.

What does it mean if an abrasive is two-body? Give an example.

Two-body abrasives are fixed, like burs or polishing disks.

What are bonded abrasives?

They are made from abrasive particles that are uniformly incorporated in a binder and bonded to a device, such as brownies and greenies.

What are coated abrasives? Give an example.

Coated abrasives have abrasive particles secured to one surface with an adhesive, such as soft rotary disks with flexible backing.

What does it mean if an abrasive is three-body? Give an example.

Three-body abrasives are free powders and pastes.

What does microparticle abrasive mean? Give an example.

Microparticle abrasives are delivered by air pressure, such as air polishing.

What grits is prophy paste available in?

Prophy paste is available in coarse, medium, fine, and super fine.

What should you follow coarse or medium grit prophy paste with?

You should follow up with super fine paste or tin oxide to smooth out scratches.

What is the Moh ranking of enamel?

The Moh ranking of enamel is 5.5-6.

What is the Moh ranking of dentin?

The Moh ranking of dentin is 3-4.

What is the Moh ranking of porcelain?

The Moh ranking of porcelain is 6-7.

What is the polishing requirement concerning Moh ranking?

1 to 2 Moh rankings above the material to be polished.

What does the ADA seal on dentifrice indicate?

The toothpaste's RDA (relative dentin abrasivity) is acceptable and does not exceed the minimal acceptable level of abrasiveness (250).

What must be done between applications of each abrasive agent?

Rinsing thoroughly to remove each abrasive agent before beginning the next.

What is margination?

The process of removing excess restorative material to bring the restoration flush with the cavosurface tooth structure.

What is the difference between flash and overhang?

Flash is extra material on the occlusal surface; overhang is extra material on the proximal or cervical area.

How soon can you polish an amalgam that has just been placed?

You can polish it 24 hours later.

How are gold alloy restorations finished and polished?

In the dental lab with diamonds, a burlew wheel, or rouge on a rag wheel.

How do you remove a stain from resin bonded margins of porcelain restorations?

Use aluminum oxide or fine/super fine grit prophy paste with intermittent pressure.

What type of PPE should be worn when polishing restorations?

A mask, eyewear, gloves, and gown should be worn.

How should clients be educated about home care for stain removal?

Regular brushing and flossing, professional cleanings, and periodic supervised whitening are recommended.