dental materilas exam 2 extras stuff

what are benfits of the 3 types of fillers (quartz, silica, & glass)

increases strength & wear resistance

- decreases thermal expansion (percolation)

- decreases shrinkage at polymerization

midi

1-10μ

mini

0.1-1μ

micro

0.01-.1μ

nano

0.001-0.01μ

What are some disadvantages of posterior composites theres 5

more costly

- easier wear than amalgam

- shrinks when cured

- micro leakage

- not indicated for large posterior restorations

What are icontraindications of sealants? there’s 2

evidence of dental caries

- partially erupted teeth

what are the results when whitening materials of the free radicals penterates too deeply

sensitivity occurs

define carbamide peroxide and their use and characstertistics theres 4

liquid/gel (10-44%)

- weaker

can be used for at home whitening but should be diluted

AVOID contact with Gingival Tissues

10% carbamide =

3% hydrogen peroxide

in-office whitening uses what

- power whitening + walking bleach

Whitening strips uses what element

- hydrogen or carbamide peroxide

Paint-on whitening paste uses what element

- hydrogen peroxide

Whitening gels in stock trays uses what element

10-22% carbamide peroxide gel

chemically-cured PMMA charasteristics there’s 4

dimensional change (24hrs)

- weaker/softer

- less color stability

- more porous (increased staining & microbes, weakens acrylic

define Gamma:

strongest

- least likely to corrode

define Gamma 1:

strong, but not as strong as gamma

define Gamma 2

: weakest

- corrodes easily

What are the disadvantages of amalgam theres 4

poor esthetics & edge strength

- tarnished with time

- high thermal conductivity

- delayed expansion

lathe-cut particles

irregular shaped

*combination is called "admired alloy"

explain high copper alloys and benefit

do NOT have a gamma-2 phase, much better clinically

describe over-triturated almagam:

wet

- decreased working time

- increased corrosion

- difficult to condense

describe condensation polymerization

- not used much in density

- produces by-products (water, H+, gas, alcohol)

the effects of creep

marginal break done

the effects of tarnish

oxidation of surface only

the effects of corrosion

weakened enamel + tooth staining / margin breakdown

the effects of dimesional change

delayed expansion

when the amount of fillers in a composite resin decreases, what also decreases

Strength and Elastic modulus (stiffness) mdodulus

when the amount of fillers in a composite resin decreases, what increases

Wear

Polymerization shrinkage
Coefficient of thermal expansion