Ch. 3, 17, 18, 22, 31, 4

Question 1

vapor pressure

Answer 1

measure of a liquid’s tendency to evaporate and become a gas

Question 2

thermal conductivity

Answer 2

rate of heat flow through a material

Question 3

heat of fusion

Answer 3

amount of energy required to melt a material

Question 4

heat of vaporization

Answer 4

amount of energy required to boil a material

Question 5

coefficient of thermal expansion

Answer 5

measure of change in volume in relation to change in temp

Question 6

viscosity

Answer 6

material’s ability to flow

Question 7

wetting

Answer 7

measured by determining contact angle of liquid on solid

Question 8

elastic deformation

Answer 8

when a stress is removed and object returns to its original length

Question 9

nonvital tooth

Answer 9

gives no response to temp change or electrical stimulus

Question 10

reversible pulpitis

Answer 10

temporary inflammation of pulp tissues, can occur if hydrogen peroxide penetrates enamel

Question 11

power whitening

Answer 11

pro in office whitening, uses higher concentrations of hydrogen peroxide

Question 12

laser whitening

Answer 12

uses argon or carbon dioxide laser beam that activates whitening agent

Question 13

carbamide peroxide

Answer 13

10-22%, dispensed into custom made resin trays

Question 14

stock mouthguard

Answer 14

available in different sizes, not preferred because of poor fit and excess bulk

Question 15

mouth-formed guard

Answer 15

boil and bite, can become distorted and does not accommodate an individual’s unique oral features

Question 16

custom made mouth guard

Answer 16

fits precisely over the individual’s dentition

Question 17

fluoride custom trays

Answer 17

good for high caries risk, xerostomia, overdentures, hypersensitivity, radiation therapy

Question 18

thermoplastic

Answer 18

polymer softens on heating and then hardens into final shape upon cooling

Question 19

light activated materials

Answer 19

you can undercure but you can’t overcure, will begin to set in ambient room light

Question 20

vital tooth whitening contraindications

Answer 20

pregnant or lactating women, children under 18 without parental consent, heavy smokers, pts who are sensitive to any ingredient in whitening agent, anterior restorations that will not be replaced

Question 21

micromechanical bonding

Answer 21

bonding using surface irregularities smaller than can be seen with the naked eye or felt with a dental explorer; advantage is that a greater number of small surface irregularities are used, force more evenly distributed; stronger

Question 22

macromechanical bonding

Answer 22

mechanism by which most glues join two pieces of wood, repair broken toys, etc; surface roughness can be seen/felt; ex. screws/nails/nuts; stress is greatly concentrated in the vicinity of fastener

Question 23

uses of adhesion/bonding

Answer 23

retention of restorations, reduction of microleakage, reduction of recurrent caries

Question 24

microleakage

Answer 24

seeping and leaking of fluids and bacteria between tooth/restoration junction or interface; increases the likelihood of recurrent caries and postoperative sensitivity

Question 25

percolation

Answer 25

repeated expansion and contraction of teeth and restorations at different rates results in fluids being sucked in and pushed out at margins of restoration

Question 26

margins

Answer 26

junction of tooth and restoration; margins that leak frequently become dark/stained

Question 27

acid etching

Answer 27

micromechanical bonding technique that was first used to retain pit and fissure sealants; reduces leakage and staining of margins

Question 28

polycarboxylate cements

Answer 28

first chemically adhesive dental cement; use polyacrylic acid and zinc oxide

Question 29

glass ionomer cements

Answer 29

use polyacrylic acid, but include glass powder instead of zinc oxide

Question 30

adhesive failure

Answer 30

type of break that occurs if adhesive comes off cleanly, when break occurs at interface

Question 31

cohesive failure

Answer 31

when failure occurs inside the bonding material

Question 32

acid etching process

Answer 32

creates “enamel tags” or “micropores”; first enamel surface is cleaned with pumice then rinsed away with water and dried with compressed air; the acid or etchant which is typically 37% orthophosphoric acid is applied for 15-30 seconds, then rinsed away and the surface is completely dried again. Next, liquid bonding resin (polymer system) is applied and it chemically reacts or “cures”. Then layers of restorative materials are chemically bonded to initial layer of bonding resin.

Question 33

why do deciduous teeth need to be etched longer than permanent teeth?

Answer 33

because the enamel rods of deciduous teeth are less regularly arranged, 30-40 sec required; should etched enamel be contaminated with saliva only a 5 sec etch is necessary

Question 34

modulus of elasticity

Answer 34

the load (stress) and change in length (strain) are proportional; this is called the proportionality constant or the slope of a graph of stress versus strain

Question 35

elastic deformation

Answer 35

when a stress is removed and the object returns to its original length

Question 36

permanently stretched out

Answer 36

plastic deformation

Question 37

poisson’s ration

Answer 37

ratio of strain in the direction of the stress to the strain in a direction perpendicular to the stress

Question 38

resilience

Answer 38

the ability to absorb energy and not become deformed

Question 39

fracture toughness

Answer 39

measure of energy required to fracture a material when a crack is present

Question 40

fatigue

Answer 40

when things fail after being stressed repetitively for a long time

Question 41

creep

Answer 41

small change in shape that results when an object is under continuous compression

Question 42

stress concentration

Answer 42

stress increases around defects

Question 43

stress relaxation

Answer 43

similar to creep, occurs slowly over time

Question 44

smear layer

Answer 44

layer of debris