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127 Cards in this Set
- Front
- Back
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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 |
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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 |
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Mercury |
used to initiate reaction with alloy |
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Class II inlay vs amalgam |
inlay: divergent walls, sharp internal line angles, reverse bevel amalgam: convergent walls, rounded internal line angles, retentive grooves |
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Overtriturated |
still has optimal strength longer trituration time smaller setting expansion want it shiny and wet |
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Class V amalgam |
retentive grooves deformed trapezoid (kidney shaped) |
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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 |
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amalgam strength |
has to do with mercury content >55% mercury dramatic loss in strength |
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Gamma |
unreacted alloy (30% amalgam) |
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Gamma one |
matrix for unreacted alloy 60%, second strongerst |
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Gamma two |
weakest, most susceptible to corrosion low copper amalgams have gamma two phase while high copper amalgams do not |
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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 |
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Gingival cavosurface margin bevel |
only if in enamel to remove unsupported ging margin trimmer |
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Mandibular first bicuspid |
tilt bur lingually to prevent encroachment on facial pulp horm |
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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 |
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Wedging |
to compensate for thickness of the matrix band |
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Polishing amalgam |
reduces marginal discrepancy, prevents tarnishing, improves appearance avoid generating heat |
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Dimensional change |
Setting expansion: more mercury, less trituration time, less pressure in condensation, greater particle size |
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Strength of amalgam |
higher condensation, smaller particle, longer trituration, fewer voids |
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cavosurface margin |
obtuse, 90 degrees (butt joint) amalgam is brittle |
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Constituents in amalgam |
most to least silver tin copper mercury high copper: less marginal breakdown less likely to corrode |
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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 |
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Free mercury |
no free mercury in triturated amalgam because trituration coats alloy particles with mercury |
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Pulp protection |
thickness of remaining dentin most important diff b/w a base, cement, and liner is their thickness |
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Cements |
15-25 micron thick |
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Cavity liners |
thin coating (5 microns) barrier to chemical irritants |
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Bases |
1 mm to 2mm substitutes for dentin barrier chemical irritants, thermal insulation, resist condensation forces |
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Glass ionomer cements |
release f, chem adhesion, therm insul, therm expan like tooth, low solubility fluoro-alumino-silicate glass that reacts with polyacrylic acid |
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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 |
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zinc polycarboxylate cement |
chemically adjesive-mainly to enamel, chelation good to pulp high tensile strength, lower compressive strength disadvantage: thick, short working time |
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rmgi luting agents |
higher strength and lower solubility and good characteristics of glass ionomers don't use with all ceramic-fracture |
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resin luting agents |
bond to dentin, high strength low solubility irritate pulp use for ceramic restorations |
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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 |
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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 |
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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 |
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Cavity liner |
not under composite: inhibits polymerization thin coatings over exposed dentin to protect pulp |
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Solution liner |
Varnish, water insolubel copalite, hydroxyline You don't need these as much anymore because of dentin bonding |
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Suspension liner |
water soluble pulpdent and hypo-cal |
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Calcium hydroxide |
released from liner or cement or base very basic react by drying |
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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 |
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Chronic caries |
shallow lesion, wide entrance, no pain |
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Acute caries |
rampant caries entrance small, lesion deep/narrow, pain, no staining, children |
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glucosyltransferase |
enzyme that strep mutans uses |
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demineralization |
pH 5.5 or below remin above |
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Step mutals |
produces lactic acid, stimulated by sucrose, |
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Light curing |
don't use UV anymore use visible light cure now |
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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 |
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Composite features |
low wear resistance |
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Microfill composite |
smallest |
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hybrids |
70-77% filled by volume |
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Microhybrids |
f |
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Flowable |
marginal adaptation of posterior composites |
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Composite filler particles |
reduces shrinkage on curing |
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Macrofills |
greater than one micron filler microfills: less |
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Filler content |
all properties of composite improved using higher filler levels: decreases fluidity though |
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Light curing methods |
hold within 2 mm, cure in increments 1.5-2 mm, cure longer for darker shades |
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Tooth prep composite |
rough walls, diamond burs, no resistance form or retention form, no base |
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Monomers for composite |
bis-gma uedma tegdma these are part of organic resin matrix questionable color stability and high viscosity |
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Methyl methacrylate |
most common acrylic used for temps cemented with zoe cement |
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lowest thermal conductivity and diffusivity |
unfilled resin high coefficient of thermal expansion |
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Acid etch |
increases surface energy, chemical cleans tooth, creates micropores for micromechanical retention 37% phosphoric acid |
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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 |
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Dentin bonding |
5th gen: two step etch and rinse 6th gen: type 2: one step self etch 7th gen: one step no mixing |
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Shoeing |
veneering non functional cusp with a finishing bevel |
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Capping |
complete coverage of functional cusp with 1.5 mm gold |
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Onlay preps |
1.0 mm gold non func 1.5 mm gold func taper lingual/buc walls |
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Gold |
increases resistance to tarnish and corrosion |
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Copper |
increases hardness |
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Silver |
modifies orange color of copper |
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Gold alloys |
I: highest gold, small inlays II: larger inlays/onlays III: onlays and crowns IV: bridges, rpds, hardest |
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Onlay prep |
all walls must converge 0.5 mm bevel on cavosurface margin: 40 degrees gingival bevel |
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Class V gold |
trapezoid or kidney outline form determined by caries |
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Sprue pin |
molten alloy reaches the mold |
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Gypsum bonded investments |
refractory filler (quartz) gives thermal expansion binder: adds strength modifiers |
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Class II gold inlay |
history of perio problems |
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Gypsum bonded gold |
used with types 1-3 gold alloys |
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Chamfer |
hollow ground bevel use bevel with gold |
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Class II onlay prep |
occlusal lock (dovetail) rounded marginal edges |
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Taper |
main reason why crowns fail 3 mm is minimal height of crown prep retention: area and parallel of axial wall |
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Retention form |
Length of walls: 3 mm minimum Taper of walls: 2-5 degrees more parallel |
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Base metal alloy |
corrosion resistant strength and low density |
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Noble metals |
very resistant to corrosion |
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Onlay bevel |
30-40 degree bevel |
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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 |
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Retention of an onlay |
parallel axial walls sharp point and line angles box/groove: box gives more retention |
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Shimstock |
check occlusion of gold crown |
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Air bubbles on gold castings |
vacuum invest them to get rid of em |
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Minimum occlusal reductions |
amalgam: 2.5/2 Cast gold: 1.5/1 PFM: 2/1.5 |
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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 |
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Rake face |
surface of blade that hits the tooth |
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Clearance face |
surface of blade away from direction of bur rotation |
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Edge angle |
angle b/w rake face and clearance face |
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Clearance angle |
angle b/w clearance face and tangent to path of rotation |
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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 |
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Hachets/chisels |
cut enamel |
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Excavators |
Hoe Angle former Hatchet Spoon excavator |
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Hoe |
class III and V gold preps |
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Angle former |
sharpen line angles |
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Hatchet |
Anterior teeth for retention |
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Spoon excavator |
removes carious dentin and carves amalgam |
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Cleoid |
pointed side of soon |
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Speed of burs |
slow under 12,000 rpm intermediate 12,000 to 200,000 high above 200,00 |
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In office bleaching |
35% hydrogen peroxide |
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At home bleeching |
carbamide peroxide 10%: ADA sealed |
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Anticholinergic |
xerostomia |
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Embrasures |
spillway for food teeth self-cleansing protect gingival tissue from friction |
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Why proper embrasures |
prevent food impaction stabilize dental arches protects periodontium |
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Premolar contacts |
Jxn occlusal and middle third |
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Molar contacts |
middle third |
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Indirect pulp cap |
CaOH base on thin layer of questionable dentin over pulp, wait 3-4 months to remove remaining decay |
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Reversible pulpitis |
pain not longer than 10 seconds short duration and low intensity tx: remove high restoration, sedative restoration, indirect pulp cap |
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Irreversible pulpitis |
pain longer than 15 seconds |
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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 |
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Sealants |
more like unfilled direct resins low viscosity |
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Fluoride |
reduces rate of enamel solubility precipitates fluorapatite remineralizes carious lesions antimicrobial |
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optimal fluoride conc in water |
around 1 ppm (0.7-1.2) |
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Hydrodynamic theory |
explains sensitivity of exposed roots to stimuli: dentinal fluid movement in tubules |
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Fluoride gel in custom trays |
rample caries xerostomia h/n radiation abutment tooh overdenture hypersensitive roots |
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Sodium fluoride |
most common otc fluoride |
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phosphate fluoride |
in office fluoride very acidic don't give on porcelain and composite |
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Toxic fluoride |
5 mg/kg body weight |
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Ductility |
ability of metal to be worked into desired shapes |
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Malleability |
metal hammered without rupture gold most ductile and malleable then silver |
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Extension for prevention |
place margins in areas of lessened caries susceptibility |
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Galvanic shock |
brief sharp electrical sensation when two similar metals touch in mouth, ends in a few days |
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Coefficient thermal expansion |
tendency of material to change shape under temperature change. gold best: close to teeth unfilled resins worst, then comp |
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done |
done |
