Chapter 13: Abrasion, Finishing, and Polishing

Chapter 13: Abrasion, Finishing, and Polishing

Complete Chapter Questions With Answers

Sample Questions Are Posted Below

MULTIPLE CHOICE

1. Proper finishing, polishing, and cleaning of tooth structures and restorative materials _____ of the restorative material.
2. improves the esthetics
3. improves the tissue health
4. increases the longevity

ANS:  A

Proper finishing, polishing, and cleaning of tooth structures and restorative materials improves the esthetics, improves the tissue health, and increases the longevity of the restorative material. The goal of finishing and polishing restorations, intraoral appliances, and tooth structure is to remove excess material, smooth roughened surfaces, and produce an esthetically pleasing appearance with minimum trauma to hard and soft tissues.

REF:   p. 204             TOP:   INTRODUCTION

2. Which of the following scales ranks materials by their relative resistance to abrasion?

ANS:  B

The Moh scale ranks materials by their relative resistance to abrasion. Diamond has the highest resistance to abrasion and is considered the hardest; pumice rates a 6 on the Moh scale, which is similar to enamel but harder than amalgam and dentin. Therefore pumice may only polish amalgam, whereas it would be abrasive to dentin.

REF:   p. 205

TOP:   Finishing, Polishing, and Cleaning (Size, Irregularity, and Hardness of Abrasive Particles)

3. Which of the following is true concerning the hardness of porcelain relative to enamel and dentin?

ANS:  A

Porcelain is harder than enamel and dentin. Abrasive wear of tooth structures in contact with porcelain restorations is a problem for many patients. The greater the difference in the abrasive and the surface it is abrading, the faster and more effective the abrasive action is.

REF:   p. 205

TOP:   Finishing, Polishing, and Cleaning (Size, Irregularity, and Hardness of Abrasive Particles)

4. Abrasive particles that are _____ will cut more efficiently.

ANS:  B

Abrasive particles that are large and irregular will cut more efficiently. The sharpness, or efficiency, of the particle is usually lost with use as the edges break down and the particle no longer grabs the surface. Unlike the shape of the particle, the size of the particle does not always break down with use.

REF:   p. 206

TOP:   Finishing, Polishing, and Cleaning (Size, Irregularity, and Hardness of Abrasive Particles)

5. Which statement explains how fine-particle diamonds are supplied?

ANS:  D

Fine-particle diamonds are supplied in a paste for polishing composite and porcelain restorations. Coated abrasives are supplied on rotary disks and handheld finishing strips. Rotary diamonds are expensive and usually are not disposable, so they are most often found bonded in varying degrees of coarseness to rotary cutting shanks or disks. Tungsten carbide finishing burs come in several shapes, with designs ranging from 7 to 30 cutting flutes.

REF:   p. 208             TOP:   Finishing, Polishing, and Cleaning (Diamond)