MCPHS Dental Materials Final Exam (all
crossword vocab)
setting expansion - the slight swelling of the gypsum while it is getting hard, crystals push against
each other creating porosities
study model cast - is a positive reproduction of both maxillary and mandibular, is a positive
reproduction of the hard & soft tissues of the oral cavity
sodium phosphate - common additive to alginate that acts as a retarder to slow down working
time
hygroscopic expansion - if the gypsum becomes immersed into water or comes in contact with
water while setting the gypsum will take-up additional water; swells
calcination - The process whereby water is lost when gypsum is heated during manufacturing
condensation silicone - impression material that is very hydrophobic, must be poured
immediately, usually has many voids
wet strength - from start of pour to one hour after, water still present
one minute - mixing time for alginate
calcium sulfate dihydrate - main component of gypsum, still contains water content
2-3 minutes - setting time of alginate
.- .
, final setting time - from start of mix to rigid mass that can be separated from impression,
minimum 1-hour/safe to separate, not fully set
10 minutes - disinfection time of alginate impression
syneresis - Water exudes causing the impression contracts
positive reproduction - study model/cast of oral structures
hysteresis - melting point much higher than boiling point, and gelling at mouth temperature
dry strength - reached in 24-hours, water has evaporated , 2X as great as wet strength
diatomaceous earth - silica, inert filler used in alginate; Gives the material 'body'
reversible hydrocolloid - impression material used for crowns, requires special equipment, water
cooled trays, can be softened and reused
exothermic reaction - gives off heat as it set or gets hard
Gilmore needle - device used to determine setting time of gypsum
Hydration - When mixed with water, the hemihydrate is converted back to dihydrate
polysulfide material - rubber base impression material, used for dentures, special spatula, long
working time 4-6 minutes
imbibition - Water may be absorbed causing the impression to swell
crossword vocab)
setting expansion - the slight swelling of the gypsum while it is getting hard, crystals push against
each other creating porosities
study model cast - is a positive reproduction of both maxillary and mandibular, is a positive
reproduction of the hard & soft tissues of the oral cavity
sodium phosphate - common additive to alginate that acts as a retarder to slow down working
time
hygroscopic expansion - if the gypsum becomes immersed into water or comes in contact with
water while setting the gypsum will take-up additional water; swells
calcination - The process whereby water is lost when gypsum is heated during manufacturing
condensation silicone - impression material that is very hydrophobic, must be poured
immediately, usually has many voids
wet strength - from start of pour to one hour after, water still present
one minute - mixing time for alginate
calcium sulfate dihydrate - main component of gypsum, still contains water content
2-3 minutes - setting time of alginate
.- .
, final setting time - from start of mix to rigid mass that can be separated from impression,
minimum 1-hour/safe to separate, not fully set
10 minutes - disinfection time of alginate impression
syneresis - Water exudes causing the impression contracts
positive reproduction - study model/cast of oral structures
hysteresis - melting point much higher than boiling point, and gelling at mouth temperature
dry strength - reached in 24-hours, water has evaporated , 2X as great as wet strength
diatomaceous earth - silica, inert filler used in alginate; Gives the material 'body'
reversible hydrocolloid - impression material used for crowns, requires special equipment, water
cooled trays, can be softened and reused
exothermic reaction - gives off heat as it set or gets hard
Gilmore needle - device used to determine setting time of gypsum
Hydration - When mixed with water, the hemihydrate is converted back to dihydrate
polysulfide material - rubber base impression material, used for dentures, special spatula, long
working time 4-6 minutes
imbibition - Water may be absorbed causing the impression to swell
