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127 Cards in this Set

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Class III

don't use composite on distal-lingual of canine (amalgam or gold)


prepare larger filling first, fill smaller one first

Ideal b/w prep and pulp

2 mm: thermal insulator, place caoh or zoe under amalgam to be a thermal insulator since amalgam is bad at that

Mercury

used to initiate reaction with alloy

Class II inlay vs amalgam

inlay: divergent walls, sharp internal line angles, reverse bevel


amalgam: convergent walls, rounded internal line angles, retentive grooves

Overtriturated

still has optimal strength


longer trituration time smaller setting expansion


want it shiny and wet

Class V amalgam

retentive grooves


deformed trapezoid (kidney shaped)



delayed expansion of amalgam

insufficient trituration/condesation and contamination of amalgam by moisture during condensation (main cause of failure)


-compressive strength reduced with combined with moisture


tooth and amalgam have different coeficcients of thermal expansion


high thermal conductor


poor thermal insulator



amalgam strength

has to do with mercury content


>55% mercury dramatic loss in strength

Gamma

unreacted alloy (30% amalgam)

Gamma one

matrix for unreacted alloy 60%, second strongerst

Gamma two

weakest, most susceptible to corrosion


low copper amalgams have gamma two phase while high copper amalgams do not

Class II amalgam

butt joint, occlusal dovetail, walls converge occlusally, bevel axiopulpal line angle bevel


2 mm amalgam functional cusps


1.5 mm amalgam for non functional cusps

Gingival cavosurface margin bevel

only if in enamel to remove unsupported


ging margin trimmer



Mandibular first bicuspid

tilt bur lingually to prevent encroachment on facial pulp horm

Divergent walls

Only mesial and distal


not buccal lingual they converge


for class I inlays also


PM from marginal ride>proximal at least 1.6 mm. 2 mm for molars



Wedging

to compensate for thickness of the matrix band

Polishing amalgam

reduces marginal discrepancy, prevents tarnishing, improves appearance


avoid generating heat

Dimensional change

Setting expansion: more mercury, less trituration time, less pressure in condensation, greater particle size

Strength of amalgam

higher condensation, smaller particle, longer trituration, fewer voids

cavosurface margin

obtuse, 90 degrees (butt joint)


amalgam is brittle



Constituents in amalgam

most to least


silver


tin


copper


mercury


high copper: less marginal breakdown less likely to corrode

Creep

process that happens over time, deformation with time in response to constant stress: main cause of marginal fracture


increase condensation decreases the creep rate

Free mercury

no free mercury in triturated amalgam because trituration coats alloy particles with mercury

Pulp protection

thickness of remaining dentin most important


diff b/w a base, cement, and liner is their thickness

Cements

15-25 micron thick

Cavity liners

thin coating (5 microns) barrier to chemical irritants

Bases

1 mm to 2mm


substitutes for dentin


barrier chemical irritants, thermal insulation, resist condensation forces

Glass ionomer cements

release f, chem adhesion, therm insul, therm expan like tooth, low solubility


fluoro-alumino-silicate glass that reacts with polyacrylic acid

Zinc phosphate cement

oldest, standard


low ph-sensitivity, no anticariogenic


superior strength: mechanical interlocking


mix very slowly: cool mixing slab, add small amounts every 20 seconds


need to apply varnish before han

zinc polycarboxylate cement

chemically adjesive-mainly to enamel, chelation


good to pulp


high tensile strength, lower compressive strength


disadvantage: thick, short working time



rmgi luting agents

higher strength and lower solubility and good characteristics of glass ionomers


don't use with all ceramic-fracture

resin luting agents

bond to dentin, high strength low solubility


irritate pulp


use for ceramic restorations

zoe sedative restoration

neutral ph


palliative on pulp


don't use on a pulp calp


low strength base under non resin restorations


interferes with subsequent placement of a resin filling



glass ionomer restorations

root caries in high risk, adheres to mineralized tooth


light cured is preferred


low stress areas


lower compressive strength, tensile strength, and hardness compared to composite


technique sensitive: high solubility


only material used as a cement and permanent restorative material

Base

Primary: placed on dentin near pulp: calcium hydroxide under comp/amal, use zinc polycarboxylate/phosphate under gold


Secondary: zinc phosphate cement over caoh base

Cavity liner

not under composite: inhibits polymerization


thin coatings over exposed dentin to protect pulp

Solution liner

Varnish, water insolubel


copalite, hydroxyline


You don't need these as much anymore because of dentin bonding

Suspension liner

water soluble


pulpdent and hypo-cal

Calcium hydroxide

released from liner or cement or base


very basic


react by drying

Carious dentin zones

Zone 1: normal dentin


Zone 2: subtransparent dentin: cpable to remineralize


Zone 3: transparent dentin: capable to remineralize


Zone 4: turbid dentin: bacterial invasion, not capable of remin


Zone 5: infected dentin outermost, totally removed

Chronic caries

shallow lesion, wide entrance, no pain

Acute caries

rampant caries


entrance small, lesion deep/narrow, pain, no staining, children

glucosyltransferase

enzyme that strep mutans uses

demineralization

pH 5.5 or below


remin above

Step mutals

produces lactic acid, stimulated by sucrose,

Light curing

don't use UV anymore


use visible light cure now



Composites

polymerization shrinkage: causes internal stresses and gap formations at butt joints


C factor: ratio of bonded and unbonded surfaces: increase in c factor is increase in polymerization shrinkage

Composite features

low wear resistance



Microfill composite

smallest

hybrids

70-77% filled by volume

Microhybrids

f

Flowable

marginal adaptation of posterior composites

Composite filler particles

reduces shrinkage on curing



Macrofills

greater than one micron filler


microfills: less

Filler content

all properties of composite improved using higher filler levels: decreases fluidity though

Light curing methods

hold within 2 mm, cure in increments 1.5-2 mm, cure longer for darker shades

Tooth prep composite

rough walls, diamond burs, no resistance form or retention form, no base

Monomers for composite

bis-gma


uedma


tegdma


these are part of organic resin matrix


questionable color stability and high viscosity

Methyl methacrylate

most common acrylic used for temps


cemented with zoe cement

lowest thermal conductivity and diffusivity

unfilled resin


high coefficient of thermal expansion

Acid etch

increases surface energy, chemical cleans tooth, creates micropores for micromechanical retention


37% phosphoric acid

Class V outline form

with composite you can make them more rounded


use a bevel with composite to stop microleakage done when the cavosurface margin is on enamel



Dentin bonding

5th gen: two step etch and rinse


6th gen: type 2: one step self etch


7th gen: one step no mixing



Shoeing

veneering non functional cusp with a finishing bevel

Capping

complete coverage of functional cusp with 1.5 mm gold

Onlay preps

1.0 mm gold non func 1.5 mm gold func


taper lingual/buc walls



Gold

increases resistance to tarnish and corrosion

Copper

increases hardness

Silver

modifies orange color of copper

Gold alloys

I: highest gold, small inlays


II: larger inlays/onlays


III: onlays and crowns


IV: bridges, rpds, hardest

Onlay prep

all walls must converge


0.5 mm bevel on cavosurface margin: 40 degrees


gingival bevel

Class V gold

trapezoid or kidney


outline form determined by caries

Sprue pin

molten alloy reaches the mold

Gypsum bonded investments

refractory filler (quartz) gives thermal expansion


binder: adds strength


modifiers



Class II gold inlay

history of perio problems

Gypsum bonded gold

used with types 1-3 gold alloys



Chamfer

hollow ground bevel


use bevel with gold



Class II onlay prep

occlusal lock (dovetail)


rounded marginal edges

Taper

main reason why crowns fail


3 mm is minimal height of crown prep


retention: area and parallel of axial wall





Retention form

Length of walls: 3 mm minimum


Taper of walls: 2-5 degrees


more parallel

Base metal alloy

corrosion resistant


strength and low density

Noble metals

very resistant to corrosion

Onlay bevel

30-40 degree bevel

Ferrule effect

if a tooth can't have a crown it can't have an onlay


envelopment of tooth structure by a crown. 1.5 mm of bucall and lingual subgingival tooth structure is sufficient


1 mm tooth thickness after prep


4 mm suprabony tooth



Retention of an onlay

parallel axial walls


sharp point and line angles


box/groove: box gives more retention

Shimstock

check occlusion of gold crown



Air bubbles on gold castings

vacuum invest them to get rid of em

Minimum occlusal reductions

amalgam: 2.5/2


Cast gold: 1.5/1


PFM: 2/1.5

Rake angle

ange b/w line connecting edge of blade to axis of bur and rake face (pos or neg)


soft materials (acrylic): positive rake angle


hard (amalgam): negative rake angle


carbide: negative rake angles



Rake face

surface of blade that hits the tooth

Clearance face

surface of blade away from direction of bur rotation

Edge angle

angle b/w rake face and clearance face



Clearance angle

angle b/w clearance face and tangent to path of rotation

Cutting instrument formular

10-85-8-14


10 mm width of blade


85 degree primary cutting edge angle


8 mm blade length


14 degree blade angle

Hachets/chisels

cut enamel



Excavators



Hoe


Angle former


Hatchet


Spoon excavator



Hoe

class III and V gold preps

Angle former

sharpen line angles

Hatchet

Anterior teeth for retention

Spoon excavator

removes carious dentin and carves amalgam

Cleoid

pointed side of soon




Speed of burs

slow under 12,000 rpm


intermediate 12,000 to 200,000


high above 200,00

In office bleaching

35% hydrogen peroxide

At home bleeching

carbamide peroxide 10%: ADA sealed

Anticholinergic

xerostomia

Embrasures

spillway for food


teeth self-cleansing


protect gingival tissue from friction

Why proper embrasures

prevent food impaction


stabilize dental arches


protects periodontium



Premolar contacts

Jxn occlusal and middle third

Molar contacts

middle third

Indirect pulp cap

CaOH base on thin layer of questionable dentin over pulp, wait 3-4 months to remove remaining decay

Reversible pulpitis

pain not longer than 10 seconds


short duration and low intensity


tx: remove high restoration, sedative restoration, indirect pulp cap

Irreversible pulpitis

pain longer than 15 seconds

Pin amaglams

one pin per missing line angle


choose largest pin possible


improves retention of large restoration, weakens the restorative material


best is 2 mm into dentin, 2 mm in amalgam, 1 mm from dej

Sealants

more like unfilled direct resins


low viscosity



Fluoride

reduces rate of enamel solubility


precipitates fluorapatite


remineralizes carious lesions


antimicrobial

optimal fluoride conc in water

around 1 ppm (0.7-1.2)

Hydrodynamic theory

explains sensitivity of exposed roots to stimuli: dentinal fluid movement in tubules



Fluoride gel in custom trays

rample caries


xerostomia


h/n radiation


abutment tooh overdenture


hypersensitive roots

Sodium fluoride

most common otc fluoride

phosphate fluoride

in office fluoride


very acidic


don't give on porcelain and composite

Toxic fluoride

5 mg/kg body weight

Ductility

ability of metal to be worked into desired shapes

Malleability

metal hammered without rupture


gold most ductile and malleable then silver

Extension for prevention

place margins in areas of lessened caries susceptibility

Galvanic shock

brief sharp electrical sensation when two similar metals touch in mouth, ends in a few days

Coefficient thermal expansion

tendency of material to change shape under temperature change.


gold best: close to teeth


unfilled resins worst, then comp

done

done