Fatigue of dental ceramics

Abstract

Objectives Clinical data on survival rates reveal that all-ceramic dental prostheses are susceptible to fracture from repetitive occlusal loading. The objective of this review is to examine the underlying mechanisms of fatigue in current and future dental ceramics. Data/sources The nature of various fatigue modes is elucidated using fracture test data on ceramic layer specimens from the dental and biomechanics literature. Conclusions Failure modes can change over a lifetime, depending on restoration geometry, loading conditions and material properties. Modes that operate in single-cycle loading may be dominated by alternative modes in multi-cycle loading. While post-mortem examination of failed prostheses can determine the sources of certain fractures, the evolution of these fractures en route to failure remains poorly understood. Whereas it is commonly held that loss of load-bearing capacity of dental ceramics in repetitive loading is attributable to chemically-assisted 'slow crack growth' in the presence of water, we demonstrate the existence of more deleterious fatigue mechanisms, mechanical rather than chemical in nature. Neglecting to account for mechanical fatigue can lead to gross overestimates in predicted survival rates. Clinical significance Strategies for prolonging the clinical lifetimes of ceramic restorations are proposed based on a crack-containment philosophy.

A multi technique study of a new lithium disilicate glass-ceramic spray-coated on ZrO2 substrate for dental restoration

“…Leucite, for example, displays an unsatisfactory failure which is revealed in a high incidence of fracture or chipping [3,8,12,14,15,25,28,[30][31][32][33]. The strong increase of chipping with time, as discussed in reference [33] for glass-ceramic veneers on ZrO 2 substrate indicates that many parameter and fatigue mechanisms contribute to eventual failure.…”

“…Today, different routes for processing are employed by the industry for all ceramic dental restoration [1,3,[11][12][13][14]. The development of new ceramics for dental restoration demands not only a high mechanical performance [15] but also aesthetical and health aspects need to be considered.…”

Correlations between fracture load of zirconia implant supported single crowns and mechanical properties of restorative material and cement

“…To predict clinical behavior of restorations, fracture load tests on crowns are performed although their significance is controversially discussed [9][10][11][12][13][14][15] . Due to differences in test set up, fracture load of restorative materials can vary significantly [10][11][12][13][14][15] .…”

Op kronen en bruggen uitgeoefende krachten en het weerstaan daarvan 2. Mechanische belastbaarheid

“…Vermoeiing, oorspronkelijk ook wel metaalmoeheid genoemd, is het fenomeen waarbij een metaal fractureert als gevolg van herhaalde belastingen die elk op zich onder de maximale mechanische belastbaarheid blijven (The glossary of prosthodontic terms, 2005). Van oorsprong was gezien deze definitie de term vermoeiing alleen van toepassing op metalen, maar inmiddels is gebleken dat ook andere materialen vermoeiing kunnen vertonen, zoals keramiek (Zhang et al, 2013). Waar het kronen en bruggen betreft uit vermoeiing zich, ongeacht het materiaal waarvan ze zijn gemaakt, als meestal aan het oppervlak beginnende microfracturen die steeds verder uitbreiden en groter worden en uiteindelijk tot een fractuur leiden (O'Brien, 2008).…”