Slow crack growth and reliability of dental ceramics

Abstract

This study provides a detailed microstructural and slow crack growth characterization of widely used dental ceramics. This is important from a clinical standpoint to assist the clinician in choosing the best ceramic material for each situation as well as predicting its clinical longevity. It also can be helpful in developing new materials for dental prostheses.

Effect of Grinding and Multi-Stimuli Aging on the Fatigue Strength of a Y-TZP Ceramic

“…Our study corroborates that assumption, since we used the methodology preconized by this systematic review (14) to avoid defect introduction (handpieces coupled to slow speed motors and the use of plenty coolant) and we did not notice a deleterious effect, even using coarse diamond burs during grinding. As stated previously, restorations clinically fail by fatigue effects (15). Previous studies about fatigue behavior of ground Y-TZP ceramics present high heterogeneity and by that gave inconclusive results.…”

“…The failure under fatigue is defined as the progressive fracture in response to cyclic forces below the monotonic strength of the material (15). Basically, cyclic forces work on existing defects resulting in the progressive growth of these defects until it achieves a critical size where the fracture occurs; this mechanism is known as slow crack growth (16).…”

Fracture statistics of dental ceramics: Discrimination of strength distributions

“…Data sets 2-5 contain different amounts of leucite (KAlSi 2 O 6 ) within a glass matrix [34][35][36]. The microstructure of a leucite-containing dental porcelain (IPS Empress I) is shown in Fig.…”

“…Such a phenomenon eventually leads to strength degradation over time. For example, due to the heterogeneous distribution of leucite clusters in porcelain, cracks are more likely to propagate through the large areas of glassy matrix, which are more susceptible to the slow crack growth [34]. For in vitro testing, the stress rate dependence of strength is a characteristic sign of SCG [50].…”

“…Then, the porous structure is infiltrated with lanthanum glass that has a low viscosity at high temperatures, so that the molten glass is able to penetrate into pores and results in a dense ceramic (see Fig. 7(a)) [34]. The alumina particles act as crack stoppers.…”