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Biomedical subjects

W G de Rijk

Publications and source records attributed to W G de Rijk.

22 records · Page 2Linked to original sources

The effect of crown length on the fracture resistance of posterior porcelain and glass-ceramic crowns.

This in vitro study measured the changes in the fracture resistance of posterior crowns as a function of crown length. The crowns, 10 for each group, were made of a feldspathic porcelain (Ceramco), a glass-ceramic material (Dicor), and an alumina-reinforced glass (In-Ceram). Three different crown lengths were tested on acrylic resin dies. The restorations were fractured in a testing machine using a steel ball, 12.7 mm in diameter, that contacted the occlusal surface at three distinct points. Statistical analysis was performed using the Weibull distribution. The fracture resistance increased significantly with increasing crown length for all crown materials.

Aluminum Oxide↗

The fracture resistance of all-ceramic crowns on supporting structures with different elastic moduli.

This in vitro study evaluated the fracture resistance of all-ceramic crowns as a function of the elastic modulus of the supporting die. All-ceramic crowns were made for dies with three different elastic moduli and two different crown lengths. The occlusal surface was loaded in compression with a 12.7-mm steel ball. The fracture load increased markedly with the increase in elastic modulus. The largest increase was seen when only the occlusal surface of the crown was covered. The characteristic fracture load of the complete-crown restorations was more than double that of the occlusal-cover restorations in the dies with the lowest modulus of elasticity, while for the dies with the highest modulus of elasticity the difference in the characteristic fracture load for the two configurations was not significant.

Chemical Phenomena↗