Influence of Connector Design on Fracture Probability of Ceramic Fixed-partial Dentures

Abstract

Fracture of ceramic fixed-partial dentures (FPDs) tends to occur in the connector area because of stress concentrations. The objective of this study was to test the hypothesis that the radius of curvature at the gingival embrasure of the FPD connector significantly affects the fracture resistance of three-unit FPDs. Two three-dimensional finite element models (FEMs), representing two FPD connector designs, were created in a manner corresponding to that described in a previous experimental study (Oh, 2002). We performed fractographic analysis and FEM analyses based on CARES (NASA) post-processing software to determine the crack initiation site as well as to predict the characteristic strength, the location of peak stress concentrations, and the risk-of-rupture intensities. A good correlation was found between the experimentally measured failure loads and those predicted by FEM simulation analyses. Fractography revealed fracture initiation at the gingival embrasure, which confirms the numerically predicted fracture initiation site. For the designs tested, the radius of curvature at the gingival embrasure strongly affects the fracture resistance of FPDs.

Effect of Connector Design on Fracture Resistance in Zirconia-based Fixed Partial Dentures for Upper Anterior Region

“…The present study aimed to exclude these factors and focus on the effects of the cross-sectional form of the connector. Many studies have reported that the curvature of the dental arch and curvature radius of the connector also influence fracture resistance 2,18,19,24) , and that the strength of an FPD framework decreases in a dynamically loaded or wet environment 3,6) . Therefore, further study is needed to elucidate the influence of connector form employing conditions as close as possible to that of the oral environment.…”

A review of dental CAD/CAM: current status and future perspectives from 20 years of experience

“…According to clinical and in vitro studies using finite element and fractographic analyses, the primary causes of failure reported for all-ceramic FPDs differed from those reported for the metalceramic FPDs. Fractures of ceramic FPDs tended to occur in the connector areas because of the concentrated stress [57][58][59][60][61] . Therefore, the design of the connector, particularly the dimensions, must be made independently depending on the type of ceramic material used for the framework.…”

Effect of Connector Design on Fracture Resistance in All-ceramic Fixed Partial Dentures for Mandibular Incisor Region

“…Being the narrowest part of an FPD, stress This paper was a thesis submitted by Dr. Murase to the Graduate School of Tokyo Dental College. tends to be concentrated on the connector, placing considerable mechanical requirements on this area 1,6,8,11) . A cross-sectional area of 9.0 mm 2 or greater has been reported to be desirable for the connector of a 3-unit Y-TZP framework in order to obtain sufficient strength 16) , and as such is recommended by many manufacturers of dental materials.…”