Dental Materials Flashcards
Inelastic impression
Plaster of paris aka impression plaster or type I stone
Elastic impressions (4)
Colloidal solutions
ZOE
Impression compounds
Elastomers
Reversible hydrocolloids are ____ from seaweeds
And is used with specialized equipments**
Agar-agar
Reversible hydrocolloids impt properties (3)
Imbibition
Syneresis
Hysteresis
Absorbs water
Imbibition - expansion
Releases water
Syneresis - syrink
Ability of material to change its form based on temperature
Hysteresis
Liquefaction temp
Gel to sol
Gelation temp
Sol to gel
Reversible hydrocolloid composition (2)
Water
Agar
Principal content of reversible hydrocolloid
Water 85%
Agar is 15% only mixed with BORAX (hardener)
Component of irreversible hydrocolloids (4)
Sodium alginate or K alginate
Ca sulfate
Diatomaceous earth
NaPO4
Major reactor of irreversible hydrocol
Sodium alginate or K alginate
Principal component of irreversible hydrocol
Diatomaceous Earth
Made from SILICA *
Flexites are made from
Nylon
ZOE contains
Oil of cloves
Contraindic for zoe (2)
Resins
Cavity varnish
Most common technique to soften impression compound
Dry heat
Water bath another one :)
First invented elastomer with the longest setting time
Polysulfide
Base and catalyst of polysulfide
Base - mercaptan
Catalyst - lead peroxide (causes foul and stains)
Least dimensionally stable among elastomers
Condensation silicones
Most dimensionally stable among elastomers
Addition silicones
Silicones
Powder/filler:____
Catalyst:____
Silica
Tin octoate
Polyether
Base:___
Catalyst:____
Polyether
Alkyl-aromatic sulfonate
Dehydrate form of gypsum
Calcium sulfate hemihydrate
Plaster of paris aka
Beta calcium sulfate hemihydrate
Type I plaster of paris
Impression plaster
Type II plaster of paris
Model plaster or study cast
Type IV gypsum
High strength stone (die stone)
Type III gypsum
Dental stone or alpha calcium sulphate hemihydrate
Gypsum retarder (2)
Borax
Na citrate
Gypsum accelerator (3)
Gypsum
Potassium sulfate
Sodium chloride
Investment for cast gold
Gypsum bonded investment
Imvestment for cast cobalt chromium
Phosphate bonded investment
Wax for bite wax
Corrective wax
Wax for boxing wax sticky wax and utility wax
Processing wax
Wax for inlay crowns rpd wax casting wax
Pattern wax
Natural waxes used in dental waxes are (3)
Paraffin
Beeswax
Carnauba
Tendency of molecule to expand or shrink depending on the temp
Coef of thermal expansiom
Best way to prevent warpage of patterns is to
Invest immediately
Best thing to do preserve dimension
Refrigerate - shrink place room temp then invest
Principal component of pattern waxes
Paraffin
Hardest structure in the world
Diamond
High noble aka
Content (2)
Examples (4)
Precious metal
>=60% noble metal
>=40% gold
Silver
Platinum
Palladium
Titanium
Noble aka
Content???
Semiprecious
>=25% noble
Base dental alloy aka
Content
Non-precious
<=25%
Hardest component used in dent (3)
Porcelain
Gold
Acrylic
Resistance to breaking under compressiom
Compressive strength
Resistance to breaking under tension
Tensile strength
Resistance to breaking or slide under horizontal forces
Shear strength
Max stress before fracturing
Ultimate tensile strength
Most important, resistance to permanent deformation
Yield strength
Rigidity or stiffness
Modulus of stiffness
Important for wear characteristics and finishing
Hardness
Change in length per 1 degree celcius change in temp
CTE
Process of joining two piece metal together through the use of lower fusing intermediate metal
Solder
Fusion temp p
100-150 degree F
Optimal space for solder
0.25 mm
Added to metal to improve flow of solder, dissolves oxides and prevent contaminatiom
Flux
Placed around the area that is to be soldered to restrict flow
Antiflux
Flame with excessive oxygen that produces oxide
Oxidizing
Flame with low oxygen. That produces carbon in metal
Reducing
Flame with balance oxygen levels
Neutral
Most common anti flux
Soft graphite pencil
Flame best to use with cast gold resto
Blue correct
Boards is REDUCING FLAME
Exposure of walls of prep to a fluid
Percolation
Principal component of dental porcelain
Feldspar
Act as matrix in dent porcelain
Feldspar
Provides skeleton and strength
Filler of porcelain
Quartz
Clay that acts as a binder opaquer and flux
Kaolin
Properties of dental porcelain (2)
CS> tensile or shear
Low plastic deformation
Saturation of hue
Chroma
Lightness or whiteness or darkness or blackness
Value
Actual color
Hue
Other component of ZOE that increases strength
Ethoxy benzoic acid
First cement that bond to tooth structure
Faster setting than zinc phosphate
Zinc polycarboxylate
Powder and liquid of zn phosphate cement
Zinc xodie
Orthophoshoric acid
Only cement that is basic
CaOH
Most soluble cement
Silicate
Least soluble cement
gi cement
First cement to the release fluoride
Silicate cements
GIC principal fluid
Polyacrylic acid
Zinc silicophosphate powder and liquid
Zinc phosphate and silicate
Phosphoric acid