Chapter 11 Terms

Question 1

what are abrasives?

Answer 1

A sharp, hard, natural or synthetic substance used for grinding, finishing, or polishing a softer surface.

Question 2

what is air particle abrasion?

Answer 2

Process of removing material, contaminants, stain, or carious tissue by use of air pressure and abrasive particles appropriate for the substrate being treated.

Question 3

what if buffing?

Answer 3

Process of producing a lustrous surface through the abrading action of fine abrasives bound to a nonabrasive carrier with or without a liquid or paste medium.

Question 4

what is bulk reduction?

Answer 4

Process of removing excess material (natural tooth or synthetic structure) by cutting or grinding with rotary instruments to provide a desired anatomic form.

Question 5

what is contouring?

Answer 5

Process of producing a desired anatomic form by cutting or grinding away excess material.

Question 6

what is cutting?

Answer 6

Process of removing material from the substrate by use of a bladed bur or an abrasive embedded in a binding matrix on a bur or disc.

Question 7

define finished and polished resto

Answer 7

A prosthesis or direct restoration whose outer surface has been progressively refined to a desired state of surface finish.

Question 8

what is finishing?

Answer 8

Process of removing surface defects or scratches created during the contouring process through the use of cutting or grinding instruments or both.

-step wise process

Question 9

what is a glazed ceramic?

Answer 9

A specially formulated ceramic powder that, when mixed with a liquid, applied to a ceramic surface, and heated to an appropriate temperature for a sufficient time, forms a smooth glassy layer on a dental ceramic surface (see natural glaze).

Question 10

define grinding?

Answer 10

Process of removing material from a substrate by abrasion with relatively coarse particles.

Question 11

define natural glaze

Answer 11

vitrified layer that forms on the surface of a dental ceramic containing a glass phase when the ceramic is heated to a glazing temperature for a specified time.

Question 12

define overglaze

Answer 12

Thin surface coating of glass formed by fusing a thin layer of glass powder that becomes a viscous liquid at a lower temperature than that associated with the ceramic substrate.

Question 13

define polish

Answer 13

Luster or gloss produced on a finished surface.

–want it to mimic enamel in the cases of ceramic, composite, porcelain, etc

Question 14

define polishing

Answer 14

Process of providing luster or gloss on a material surface.

Question 15

cannot use the same type of abrasive for different kinds of material (e.g. amalgam, ceramics, gold)

Answer 15

ye

Question 16

In summary, dental abrasives are used for tooth cleaning (dental prophylaxis), occlusal adjustment of tooth enamel and restoration surfaces, contouring of material (acrylic, composite, metal, and ceramic) surfaces, nishing and debris removal (grinding and air-particle abrasion), and ne pol- ishing to produce glossy surfaces

Answer 16

ye

Question 17

Finished and polished restorations provide four bene ts of dental care: better gingival health, chewing e ciency, patient comfort, and esthetics, reduces tarnish and corrosion, reduces wear rates of opposing teeth, increases strength (rough surface = stress conc)

Answer 17

ye

Question 18

Smoother sur- faces have less retention areas and are easier to maintain in a hygienic state when preventive oral home care is practiced because dental oss and the toothbrush bristles can gain more complete access to all surfaces and marginal areas.

Answer 18

ye

Question 19

flutes on burs go up for cutting, contouring, then finishing

Answer 19

ye

Question 20

what is silicosis?

Answer 20

grinder’s disease; continuous inhalation of grinding aerosols;

debilitating lung disease, fibrosis of alveoli, inhibit air exchange

Question 21

abrasion is a type of wear–two surface gliding past each other

Answer 21

ye

Question 22

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

Answer 22

HOWEVER Chemical erosion, more commonly called acid etching in dentistry, is not used as a method of finishing dental materials

Question 23

As stated previously, the inherent strength of cutting blades or abrasive particles on a dental instrument must be great enough to remove particles of substrate material without becoming dull or fracturing too rapidly.

Answer 23

ye

Question 24

Mohs, Knoop, and Vicker’s hardness

Answer 24

ye

Question 25

what is truing?

Answer 25

Truing is a procedure by which the abra- sive 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

Question 26

what is dressing and what does it do?

Answer 26

e dressing procedure, like truing, is used to shape the instru- ment, but it accomplishes two di erent purposes as well. First, the dressing procedure reduces the instrument to its correct working size and shape. Second, it is used to remove clogged debris from the abrasive instrument to restore grind- ing e ciency during the nishing operation.

Question 27

what are nonbonded abrasives?

Answer 27

gel, pastes, etc

Question 28

Dental composites are among the most difficult types of materials to predictably nish and polish to a high luster because they contain a relatively so resin matrix and hard ller particles in their structures.

Answer 28

ye