Abstract: Objective To establish a three-dimensional finite element model of the mandibular first premolar wedge-shaped defect and different material inlay restorations, and carry out stress analysis to provide a theoretical reference for clinical inlay restoration of wedge-shaped defects. Methods The raw data of the tooth were obtained by CBCT scanning. The wedge-shaped defect model and the three-dimensional finite element model of the mandibular first premolar were established by Mimics 17.0 and Geomagic Studio 13.0 software, and respectively treated with the resin inlay (A), porcelain inlay (B) and the gold alloy inlay (C), and the undefended wedge-deficient model was used as the control group. Then the stress analysis of the tooth neck was performed using Abaqus 6.14 finite element software. Results From the stress distribution, there were two stress concentration areas in the residual tooth structure and the inlay restoration model after the vertical load wedge defect. The main stress of the remaining tooth body tissue model after wedge deficiency was concentrated in the wedge defect. The main stress of the inlay restoration model was in the neck of the tooth. It was found that the maximum principal stress values of the inlays of different materials were significantly reduced. Conclusion The inlays of different materials can repair the wedge-shaped defect and improve the stress concentration near the defect. The porcelain inlay (B) and the gold alloy inlay (C) are ideal compared with the resin inlay (A).

Key words: Inlay, Wedge-shaped defect, threedimensional finite element, stress