Lifetime prediction of CAD/CAM dental ceramics

Abstract

The dynamic fatigue method was used to obtain subcritical crack growth parameters n and A for a commercial feldspathic dental porcelain and for a lanthanum-glass-infiltrated alumina glass ceramic. Five stress rates d sigma/dt ranging from 50 to 0.01 MPa s(-1) were applied. The inert strength values were calculated with the use of Weibull statistics and maximum-likelihood approaches for the Weibull parameter m. Strength-probability-time (SPT) diagrams were derived for both materials. The alumina glass composite showed a high fracture strength sigma(0) (442 MPa) at a failure probability of P(F) = 63.2% and a high resistance against subcritical crack growth (n = 36.5). The development of strength under fatigue conditions was calculated for exemplary 1 year. The strength of the alumina glass material dropped to 228 MPa within this period. This fact is due to a low content of infiltrated lanthanum glass phase in the composite material (25 wt%). In contrast, for the high-silica-glass-containing porcelain a distinct decrease of strength sigma(0) from initial 133 to 47 MPa after 1 year was predicted. This, mainly because of a low crack growth resistance (n = 16.8) of the feldspathic porcelain. Much lower strength values were calculated, assuming a failure probability of P(F) = 5%. The decrease is mainly caused by the sensitivity of high-glass-containing ceramics against water corrosion.

Determination of the slow crack growth susceptibility coefficient of dental ceramics using different methods

“…The n d values determined in the constant stress‐rate test were similar to those reported in the literature for veneering ceramics (from 15 to 41)5, 13, 26, 31, 37, 38, 41, 43, 44; for leucite‐ and lithium disilicate‐based glass‐ceramics (from 20 to 31)5, 39, 40, 45, 46; and for glass‐infiltrated alumina composites (from 16.5 to 36.5) 38, 47. These studies also used indirect methods for the determination of n .…”

Determination of the slow crack growth susceptibility coefficient of dental ceramics using different methods

“…The n d values determined in the constant stress‐rate test were similar to those reported in the literature for veneering ceramics (from 15 to 41)5, 13, 26, 31, 37, 38, 41, 43, 44; for leucite‐ and lithium disilicate‐based glass‐ceramics (from 20 to 31)5, 39, 40, 45, 46; and for glass‐infiltrated alumina composites (from 16.5 to 36.5) 38, 47. These studies also used indirect methods for the determination of n .…”

Scaling of strength and lifetime probability distributions of quasibrittle structures based on atomistic fracture mechanics

“…Fig. 1 H-K documents further close fits of histograms of flexural strength of various industrial and dental ceramics (32)(33)(34). Previous investigators fitted them closely by the 3-parameter Weibull distribution with a nonzero threshold, though with unreasonably small Weibull moduli m. It is now clear that close fits were possible because only a few hundred tests were made.…”

Monolith Dental Bridge by Soft Machining of Dried Ceramic Dough

“…In addition, final strength depends on the interplay of different processing parameters, such as sintering time, temperature, doping, and grain size distribution. Further, both the alumina and YSZ processed by this dough process as presented in the previous study showed strength greater than those reported for ceramics used in dental restorations (34,35). The longevity of a dental restoration under constant cyclic loading and a complex set of masticatory forces is influenced by fatigue in the prosthesis.…”

Determination of the slow crack growth susceptibility coefficient of dental ceramics using different methods

“…The n d values determined in the constant stress‐rate test were similar to those reported in the literature for veneering ceramics (from 15 to 41)5, 13, 26, 31, 37, 38, 41, 43, 44; for leucite‐ and lithium disilicate‐based glass‐ceramics (from 20 to 31)5, 39, 40, 45, 46; and for glass‐infiltrated alumina composites (from 16.5 to 36.5) 38, 47. These studies also used indirect methods for the determination of n .…”

Scaling of strength and lifetime probability distributions of quasibrittle structures based on atomistic fracture mechanics

“…Fig. 1 H-K documents further close fits of histograms of flexural strength of various industrial and dental ceramics (32)(33)(34). Previous investigators fitted them closely by the 3-parameter Weibull distribution with a nonzero threshold, though with unreasonably small Weibull moduli m. It is now clear that close fits were possible because only a few hundred tests were made.…”

Monolith Dental Bridge by Soft Machining of Dried Ceramic Dough

“…In addition, final strength depends on the interplay of different processing parameters, such as sintering time, temperature, doping, and grain size distribution. Further, both the alumina and YSZ processed by this dough process as presented in the previous study showed strength greater than those reported for ceramics used in dental restorations (34,35). The longevity of a dental restoration under constant cyclic loading and a complex set of masticatory forces is influenced by fatigue in the prosthesis.…”

Determination of the slow crack growth susceptibility coefficient of dental ceramics using different methods

“…The n d values determined in the constant stress‐rate test were similar to those reported in the literature for veneering ceramics (from 15 to 41)5, 13, 26, 31, 37, 38, 41, 43, 44; for leucite‐ and lithium disilicate‐based glass‐ceramics (from 20 to 31)5, 39, 40, 45, 46; and for glass‐infiltrated alumina composites (from 16.5 to 36.5) 38, 47. These studies also used indirect methods for the determination of n .…”

Scaling of strength and lifetime probability distributions of quasibrittle structures based on atomistic fracture mechanics

“…Fig. 1 H-K documents further close fits of histograms of flexural strength of various industrial and dental ceramics (32)(33)(34). Previous investigators fitted them closely by the 3-parameter Weibull distribution with a nonzero threshold, though with unreasonably small Weibull moduli m. It is now clear that close fits were possible because only a few hundred tests were made.…”

Monolith Dental Bridge by Soft Machining of Dried Ceramic Dough

“…In addition, final strength depends on the interplay of different processing parameters, such as sintering time, temperature, doping, and grain size distribution. Further, both the alumina and YSZ processed by this dough process as presented in the previous study showed strength greater than those reported for ceramics used in dental restorations (34,35). The longevity of a dental restoration under constant cyclic loading and a complex set of masticatory forces is influenced by fatigue in the prosthesis.…”