Evaluation of mechanical and thermal stress in an endodontically treated cracked premolar with three restorative designs: 3D-finite element analysis

Purpose: We aimed to analyze the influence of different designs (inlay, onlay, and crown) on stress distribution and crack propagation in an endodontically treated cracked premolar.

Methods: Three-dimensional (3D) finite element analysis (FEA) was employed to model an endodontically treated cracked premolar with three different restorations (inlay, onlay, and crown). Six types of loadings (vertical loading of 600 N; hot thermal-600 N vertical coupling loading; cold thermal-600 N vertical coupling loading; oblique loading of 200 N; hot thermal-200 N oblique coupling loading; cold thermal-200 N oblique coupling loading) were applied to simulate the hot and cold food/beverages intake. The Von-Mises Stress (VMS) on the lower margin of the crack surface was measured at 20 points in each model, and the position of the stress concentration on the crack surface was analyzed.

Results: All three restoration types effectively improved stress distribution. The influence of different restorative modalities on the stress distribution at the crack tip exhibited different trends under different loading conditions. Lateral loading and/or hot thermal cycling increased the intensity of VMS, and crown restoration exhibited the highest stress concentration at the crack tip under lateral loading and hot thermal cycling.

Conclusions: From a mechanical perspective, the outcome of this study suggested that a full crown restoration is not the optimal choice for preventing further crack propagation. Additionally, it is recommended to reduce the consumption of excessively hot foods and beverages daily.