Introduction: The purpose of this study was to investigate the influence of access cavities and tapers of canal preparations on fracture resistance of endodontically treated first molars by finite element method and Weibull analysis.
Methods: On the basis of the micro-computed tomography data of maxillary first molar, the models of endodontically treated teeth with conservative endodontic cavity, traditional endodontic cavity, and 4 tapers of canal preparations (0.02, 0.04, 0.06, and 0.08) were created. Four static loads (800 N in total) were applied vertically to the contact points. The stress distributions of maximum principal stress were recorded and analyzed. Weibull analysis was performed to analyze the failure risk in enamel and dentin.
Results: The stress distributions of maximum principal stress on occlusal surfaces were similar. In cervical region, the tensile stress was mainly concentrated on mesiobuccal root and root furcation. The finite element analysis and Weibull analysis showed that conservative endodontic cavity significantly reduced the maximum principal stress in cervical region and the failure probability, compared with traditional endodontic cavity. No significant difference was detected among tapers of prepared canals.
Conclusions: Preserving coronal dentin by using conservative endodontic cavity significantly reduced the concentration of tensile stress and the failure probability of dentin, although the maximum principal stress and failure probability were less affected by taper of canal preparation.
Keywords: Access cavity; canal taper; failure probability; minimally invasive.
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