12
Inelastic impression materials
Component | Addition level (%) |
---|---|
Thermoplastic (rosin, copal resin, carnauba wax) | 47 |
Lubricant (stearic acid) | 3 |
Filler (talc) | 50 |
Material | Flow at 37°C | Flow at 45°C |
---|---|---|
Type I (impression compound) | <6% | >85% |
Type II (tray compound) | <2% | 70–85% |
Base paste | Reactant |
---|---|
Zinc oxide, 85% Inert oil, 15% |
Eugenol, 15% Rosin, gum, oil, 65% Filler (talc, kaolin), 16% |
Impression materials, central to fabricating all fixed and removable prostheses, fall into two broad categories, inelastic and elastic. The former are used for edentulous patients and for interocclusal records whereas the latter (Chapter 13) are for dentate patients.
12.1 Factors in impression-making
An impression material must wet the hard a/>