3: Physical properties of materials

3

Physical properties of materials

Figure 3.1 Effect of temperature rise on a restoration and tooth with different coefficients of thermal expansion.

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Table 3.1 Thermal properties of various dental materials

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Table 3.2 Coefficients of thermal expansion

Material Coefficient of thermal expansion (×10−6/°C)
Tooth (crown portion) 11.4
Amalgam 22.1–28.0
Gold 14.4
Composite resin 17–50
Acrylic resin 76.0
Porcelain 12.0
Glass ionomer 10.2–11.4
Inlay wax 350–450
Silicone impression material 210
Polysulfide impression material 140

Table 3.3 Electrical constants for dental materials and teeth

Material Resistivity (Ω·cm) Dielectric constant
Tooth enamel 2.6–6.9 × 106
Dentin 1.1–5.2 × 104 8.6
Glass ionomer 0.8–2.5 × 104 2–7 × 105
Zinc oxide–eugenol 109–1010 10
Zinc polyacrylate 0.4–4 × 105 4 × 103–2 × 105
Zinc phosphate 2 × 105

Table 3.4 Wavelengths of visible light

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Jan 1, 2015 | Posted by in Dental Materials | Comments Off on 3: Physical properties of materials
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