12: Inelastic impression materials

12

Inelastic impression materials

Figure 12.1 Structure of eugenol.

c12-fig-0001

Figure 12.2 Structure of zinc eugenolate.

c12-fig-0002

Table 12.1 Impression compound

Component Addition level (%)
Thermoplastic (rosin, copal resin, carnauba wax) 47
Lubricant (stearic acid) 3
Filler (talc) 50

Table 12.2 Flow properties of impression and tray compound

Material Flow at 37°C Flow at 45°C
Type I (impression compound) <6% >85%
Type II (tray compound) <2% 70–85%

Table 12.3 Zinc oxide–eugenol impression material

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/>

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Jan 1, 2015 | Posted by in Dental Materials | Comments Off on 12: Inelastic impression materials
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