Card Set Information
the purpose of an impression is to make a _________ reproduction of teeth and tissues then once poured in gypsum is to make a _______ reproduction of teeth and tissues
what are the two hydrocolloids, give examples
what are three types of elastomers
what are the two categories of elastic impressions
hydrocolloids and elastomers
what are three types of inelastic materials?
plaster-type I gypsum
reversible hydrocolloid unergoes what type of reaction?
the solid to gel state of a reversible hydrocolloid is temperautre dependent?
temp solidifies but not temp liquifies
contract and squeeze out liquid
reversible hydrocolloid (agar) is popular for ______ preparations but ______
solidification by called is called?
______ ______ is needed for proper set gypsum for the reversible hydrocolloid
what is the gel strengthener for reversible hydrocolloid?
what is the antifungal for the reversible hydrocolloid?
_____ and _____ retard set of gypsum products
borax and agar
what cancels the effect of borax and agar?
what are three advanatages to the reversible hydrocolloid (agar)
an example of irreversible hydrocolloid is?
what type of reaction does irreversible hydrocolloid undergo?d
t/f irreversible hydrocolloid is temperature dependent by
false not temperature dependent
how can you delay or accelerate the setting up of irreversible hydrocolloid (alginate)
t/firreversible hydrocolloids are susceptible to imbibition but not syneresis
false susceptible to both
what is the most widely used impression material?
irreversible hydrocolloid (alginate)
what is added to keep alginate from interfering with set of gypsum products?
what is the mixing time for regular set alginate?
what ist he workingtime for fast set alginate?
what is not recommended with preparing alginate to affect the setting time?
adjusting water to powder ration
how long do you rinse and disinfect an impression
you must pour an impression within _____ hour of taking the impression, why?
looses moisture and changes shape
why does an impression change shape over time?
due to water loss (shrinkage)
what must be covered on the maxillary of an impression? mandibular?
when loading a tray you load ____ increments and load ____
a right handed clinician must stand _____ pt at ____oclock position
a left handed clinician must stand _____ pt at ___oclock position
hydrocolloids are _____ and elastomers are ___ _____
t/f elastomers are hydrophobic
silicone rubber is a ______ reaction silicion
polyvinyl siloxane (PVS) is ______ reaction silicion
what type of material has the smallest dimensional change?
polyvinyl siloxane PVS
when must you pour a PVS impression
within one week
what type of gloves must be worn when mixing PVS? why?
latex interferes with set
what type disinfectants are appropriate for alginate and silicone
how long must you disinfect an impression?