Ch. 5, 36, 32

Question 1

polymers

Answer 1

materials made of large, long molecules formed by chemically reacting molecular building blocks called monomers; common polymers or plastics include polyethylene, Plexiglas

Question 2

polymerization

Answer 2

links monomers together to produce polymer

Question 3

thermoplastic

Answer 3

can be heated and molded to shaped after polymerization reaction

Question 4

thermoset polymers

Answer 4

polymers with a cross-linked rather than a linear structure tend not to melt, rather they decompose, can’t be heated or molded, tend to be stronger, most dental resins are cross-linked and are therefore thermoset

Question 5

free radicals

Answer 5

the polymerization reaction of acrylic resins is called free radical or addition polymerization; a free radial or unpaired electron is involved in reaction and one monomer is added at a time to polymer chain as reaction proceeds

Question 6

initiation

Answer 6

first step in addition polymerization; first formation of free radicals then the free radical reacts with a monomer molecule to start a growing chain

Question 7

propagation

Answer 7

second step in addition polymerization, which is the growth or lengthening of the chain; involves adding the 2nd, 3rd, 4th, and later monomers to the growing chain until that chain is hundreds/thousands of monomers long

Question 8

termination

Answer 8

two free radicals at the ends of two growing chains may react; if they do, they will form a carbon-carbon bond; at this point, no free radicals are left to continue growth of the chain

Question 9

heat activated acrylic resins

Answer 9

typically use benzoyl peroxide as the initiator, heat is the activator, in hot water bath; most complete and partial dentures use heat-activated acrylic resins for denture base

Question 10

chemically activated

Answer 10

use BPO as initiator, tertiary amines as activator; used to make temp crows, ortho retainers

Question 11

light activated

Answer 11

use several activator and initiator chemicals; the activator absorbs light and then reacts with the initiator; supplied as single paste

Question 12

dual-cure

Answer 12

have both chemical and light-activated capabilities

Question 13

working time

Answer 13

can occur very rapidly, an inhibitor, typically hydroquinone reacts with the first free radicals that are produced during the initiation process, this reaction competes with polymerization process and wins

Question 14

percolation

Answer 14

repeated expansion and contraction can open and close gaps at the margin of a restoration, can result in leakage and recurrent caries

Question 15

macrofilled composite

Answer 15

first type of dental composite, large size of filler particles in macrofilled composites results in a restoration that feels rough to explorer and can appear rough to the eye

Question 16

microfilled composite

Answer 16

particle size far smaller, will polish smooth and lustrous

Question 17

hybrid composite

Answer 17

are strong and polish well

Question 18

flowable composites

Answer 18

flow into cavity prep b/c of lower viscosity, used as initial increment then covered with a hybrid material

Question 19

condensable composites

Answer 19

have a filler particle feature that inhibits the filler particles from sliding by one another

Question 20

finishing composite

Answer 20

contours are corrected while margins and irregularities are smoothed

Question 21

polishing composite

Answer 21

produces smooth lustrous finish

Question 22

evaluating restoration

Answer 22

it is useful to dry tooth, then visually inspect the contours to detect anatomical form, chips, voids, strains, or defects, check occlusion, look at margins, check with dental floss

Question 23

scalpel blade

Answer 23

most effective instrument to remove interproximal overhangs and flash

Question 24

flame-shaped finishing burs

Answer 24

can be used to smooth contours and margins and remove overhangs

Question 25

finishing disks

Answer 25

useful when the restoration extends onto the facial or lingual surface thereby allowing access to the area

Question 26

finishing strips

Answer 26

the center contains no abrasives, position the strip both on tooth structure and restoration and gently pull strip over surface

Question 27

egg or football shaped finishing burs

Answer 27

can be used to complete all occlusal finishing

Question 28

finishing points and cups

Answer 28

used to smooth the surface and grooves

Question 29

flame shape finishing burs

Answer 29

can be used to contour surfaces, smooth margins, and remove flash

Question 30

debonding

Answer 30

complete removal of the composite and cement material from enamel surfaces after appliances are removed

Question 31

debonding procedure

Answer 31

identify resin, remove resin bulk, final finishing

Question 32

tips for clinician during debonding

Answer 32

during use of bur, apply air frequently to dry tooth and examine surface; make sure the pt moved his or her tongue over each tooth surface slowly to detect any residual resin, emphasize importance of office and home fluoride to remineralize enamel after debonding; begin the stroke with the bur at the cervical portion of the resin and move toward the incisal or occlusal surface to avoid accidental trauma to gingiva