Effects of different tooth preparations on the fracture behavior of teeth with severe wedge-shaped defect restored with post and core crowns / 华西口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>This study aimed to investigate the effects of different tooth preparations on the fracture strength and pattern of failure of teeth with severe wedge-shaped defect restored with post and core crowns.</p><p><b>METHODS</b>According to whether the teeth above the wedge-shaped defect was removed (represented by B) or not (represented by A), the ferrule next to the wedge-shaped defect was prepared (represented by D) or not (represented by C), the cast post-and-core was chosen (represented by E) or glass-fiber post and resin core was chosen (represented by F). A total of 64 human mandibular premolar teeth were randomly divided into 8 groups A1-1 (A + C + E), A1-2 (A + C + F), A2-1 (A + D + E), A2-2 (A + D + F), B1-1 (B + C + E), B1-2 (B + C + F), B2-1 (B + D + E), B2-2 (B + D + F), each group 8 teeth. All the teeth were prepared and restored accordingly and then mounted on an electronic pressure universal testing machine. The maximum fracture strength and the patterns of failure were recorded.</p><p><b>RESULTS</b>1) The fracture strength of Group A1-1 > that of Group B1-1, Group A1-2 > Group B1-2, Group B2-1 > Group B1-1, and Group B2-1 > Group B2-2 with significant differences (P < 0.05). 2) The patterns of repairable fracture in Group A1-2 and B1-2 were both 37.5%, and that of the other groups were 0. Furthermore, the difference was significant, and Group A1-2 and B1-2 were higher than other groups.</p><p><b>CONCLUSION</b>The maintenance of the overhang above the severe wedge-shaped defect aid in the improvement of the fracture strength of the tooth restored with post and core crown. The ferrule of the wedge-shaped defect is not recommended to be prepared. Furthermore, the glass-fiber post and resin core is favorable for the re-repair of the teeth than the cast post and core.</p>