Fracture Strength and Fatigue Resistance of All‐Ceramic Molar Crowns Manufactured with CAD/CAM Technology

Abstract

The performance of VMII crowns was superior to YZ crowns in the fatigue test. The premature fractures and cracks of the YZ crowns were attributed to weakness in the YZ veneer layer or in the core/veneer bond.

Laboratory Simulation of Y-TZP All-ceramic Crown Clinical Failures

“…The intermediate elastic modulus of zirconia is an advantage in reinforced layered structures, shifting damage and fracture modes into the porcelain veneer layer (Kim et al, 2007a). Only recently reported is a fatigue study on anatomically correct crowns which reported cohesive failure in the porcelain veneer and in the veneer/core bond (Zahran et al, 2008). This study used uni-axial loading, where the tooth-cusp-simulating indenter did not lift off the porcelain.…”

Fitting accuracy and fracture resistance of crowns using a hybrid zirconia frame made of both porous and dense zirconia

“…The fracture load on the crowns with a dense zirconia frame was 1,930 N and on those with a commercial zirconia frame was 1,863 N. Larrson et al 23) reported that the fracture load of a crown with a dense zirconia frame made by milling a completely sintered zirconia block in the same manner as was done in our experiment was 1,800 N; and Ereifej et al 24) and Zahran et al 25) also stated in their reports that the fracture load of a crown with a dense zirconia frame designed for a lower molar was 2,081 N (Ereifej) and 1,459 N (Zahran) . However, one cannot compare these results one-for-one, because the experimental conditions including the abutment design, the shape and location of the crowns, the point of loading and the loading method varied from one experiment to another.…”

“…In previous reports [23][24][25] , there were fractures or dislodgements of the porcelain veneer from frames after fracture testing. By contrast, for five of the seven crowns with a hybrid zirconia frame, the zirconia frame fractured with the veneering porcelain still stuck to it, exposing the abutment tooth.…”

Farkli Güdük Materyalleri̇, Saklama Ortami Ve Si̇manin Zi̇rkon Alt Yapilarinin Kirilma Di̇renci̇ Üzeri̇nde Etki̇si̇

“…Bu yüzden çalıĢmamız in vitro ortamda gerçek-leĢtirilmiĢtir. 37 Tam seramik kuronlarda kırılma dayanı-mının değerlendirildiği çoğu çalıĢmada güdük materyali olarak metal 21,38,39 , pirinç 40,41 , epoksi rezin 21,38,42,43 ve dentin 21,44 kullanılmıĢtır. Bu çalıĢmada da bu amaçla klinik ortamı taklit edebilmek ve standardizasyonu sağlayabilmek için dentinin elastik modülüne yakın güdük materyali arayıĢına girilmiĢtir.…”