Finite element and Weibull analyses to estimate failure risks in the ceramic endocrown and classical crown for endodontically treated maxillary premolar

Abstract

The present study evaluated the failure risks of an endodontically treated premolar with severely damaged coronal hard tissue and restored with either a computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic endocrown or a classical crown configuration. Two, three-dimensional finite element maxillary premolar models were designed with endodontic treatment and restored with either a chairside economic reconstruction of esthetic ceramic (CEREC) ceramic endocrown or a classical crown. The Weibull function was incorporated with finite element analysis to calculate the long-term failure probability relative to different load conditions. Additionally, an in vitro fatigue-load fracture experiment was performed to validate the numerical simulation results. The results indicated that the stress values on the dentin and luting cement for the endocrown restoration were lower than those for the crown configuration. Weibull analysis revealed that the individual failure probability in the endocrown dentin and luting cement diminished more than those for the crown restoration. While the overall failure probabilities for the endocrown and the classical crown were similar, fatigue fracture testing revealed that the endocrown restoration had higher fracture resistance than the classical crown configuration (1,446 vs. 1,163 MPa). This investigation implies that the endocrown can be considered as a conservative, aesthetic, and clinically feasible restorative approach for endodontically treated maxillary premolars.

A comparison of the fracture resistances of endodontically treated mandibular premolars restored with endocrowns and glass fiber post-core retained conventional crowns

“…In previous studies, there has been considerable disagreement about the endocrown as an available method for premolars. Some studies found that endocrowns for endodontically treated maxillary premolars had higher fracture resistance than the conventional restorations,1617 while others reported that endocrowns appeared inadequate for premolars compared with conventional crowns 2021. Moreover, there has not been any recommendation about the validity of the endocrown for endodontically treated mandibular premolars, which have quite different anatomic forms from maxillary premolars.…”

“…Several in vitro studies have reported that molars and maxillary premolars with ceramic endocrowns showed better fracture resistance than those with conventional postcore supported ceramic crowns 151617. However, there were few studies about the fracture strength of endocrowns of the mandibular premolars, whose coronal and radicular geometries are quite different from their maxillary counterparts.…”

Fracture Resistance and Microleakage of Endocrowns Utilizing Three CAD-CAM Blocks

“…This approach has shown promising results and comparable short-term survival when compared to post, core, and crown systems. [18][19][20][21][22] A wide collection of ceramic materials has been available for CAD/CAM technology, ranging from relatively weak feldspathic ceramic and leucite glass ceramic to high-strength lithium disilicate glass ceramic and zirconium oxide. 23 Most recently, a resin nanoceramic has been introduced for permanent CAD/CAM fabricated restorations.…”

Fracture Strength and Retention of All-Ceramic Endocrowns Luted Using Two Different Resin Cements

“…This result was in agreement with other studies which observed higher fracture loads for endocrowns compared to fiber post and core supported crowns. (13,19,22) The root resistance to fracture is directly related to the volume of remaining dentin. (23) Study was reported that thicker root dentin walls significantly increase the fracture resistance of endodontically treated teeth.…”

“…(12) The surfaces available within the pulp chamber obtain stability and retention of the restoration through adhesive bonding. (13) This type of restoration can be fabricated through computeraided design/computer aided manufacturing (CAD/ CAM) technology, providing the possibility for chair-side design and fabrication. (14) The advantages of endocrowns over foundation restorations can be summarized as follows: they reduce the interfaces of the restorative systems, they have ability of restoring teeth with insufficient vertical dimension, they can restore badly broken down teeth while preserving the maximum tooth structure rendering more efficient and aesthetic results and they also reduce the need for macroretentive geometry.…”