40: Strengthening porcelain

40

Strengthening porcelain

Figure 40.1 Reinforcing filler particle acting as a “crack stopper” for a propagating crack.

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Figure 40.2 Schematic representation of a PFM (metallo-ceramic) crown.

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Figure 40.3 Schematic representation of a crown constructed with a glass-infiltrated (In-Ceram) core.

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Table 40.1 Strengths of dental hard tissues and dental ceramics

Material Flexural strength (MPa) Fracture toughness (MN/m3/2)
Enamel 65–75 1
Dentin 16–20 2.5
Feldspathic porcelain 60–110 1.1
Leucite porcelain 120–180 1.3
Aluminous porcelain 130–140 2.0
Glass-infiltrated alumina 400–600 4–6
Spinel-infiltrated alumina 325–410 2.4

Porcelain restorations can be fabricated in a range of shades and translucencies that, with esthetics and chemical resistance, make them almost ideal replacements for lost hard tissue. Further, being a good thermal insulator, porcelain protects the pulp against heat insult even with marked hard tissue loss.

Limitations of porcelain were indicated in Chapter 39. Despite improvements that are possible by control/>

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Jan 1, 2015 | Posted by in Dental Materials | Comments Off on 40: Strengthening porcelain
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