Reliability of reduced-thickness and thinly veneered lithium disilicate crowns

A selection of abstracts of clinically relevant papers from other journals. The abstracts on this page have been chosen and edited by John R. Radford.

Abstract

Metal ceramic crowns would still be considered the 'gold standard'.

Main

Silva NRFA, Bonfante EA et al. J Dent Res 2012; 91: 305–310

The step-stress method, fractography of post mortem specimens and Weibull modulus (that reflects the variability in strength of brittle materials) was calculated in order to examine the 'reliability' of different materials used to fabricate ceramic crowns. There was no difference between the Weibull characteristic failure loads of monolithic IPS e.max^™ CAD crowns (1 mm thickness) and those veneered with fluorapatite ceramic. They also found that these lithium disilicate crowns had superior mechanical characteristics compared with zirconia crowns. Figure 3 contextualises some of the laboratory findings by showing a clinical photograph of the degradation of an e.max^™ CAD crown. When considering zirconia crowns, it was reported that modifications to core/framework design has reduced veneer chipping. Nevertheless, such failure is still higher than that for metal ceramic crowns.