Effects of the remaining amount of tooth on the fracture mode of fiber post-core full crown restoration / 中国组织工程研究

ABSTRACT

BACKGROUND:Studies have demonstrated that implantation of pile and different amount of residual tooth can change the stress distribution patterns of the tooth dentin within the residual root, and have an effect on the fracture mode of post-core restoration. OBJECTIVE:To evaluate the effects of the different amount of residual tooth on the fracture mode under oblique loading conditions in fiber pile composite resin core ful crown restoration. METHODS:Forty single rooted premolars extracted from orthodontic patients were divided into four groups after root canal preparation and filing. The plane going through buccal and lingual enamel cementum border midpoint and perpendicular to the long axis of the tooth was taken as the reference plane, so that the remaining amount of the tooth were 0, 1, 2, 3 mm. Fiber pile composite resin core metal ful restoration was conducted. After the repair, the oblique loading at 45° and at the rate of 1 mm/min was conducted. Fracture mode and load-displacement curve when root fracture occurred were recorded. RESULTS AND CONCLUSION:The tooth neck fracture usualy occurred in the 0 mm group, and central root fracture usualy occurred in the remaining three groups. There was a significant difference in the total fracture mode between 0 mm group and the remaining three groups (P 0.05). In oblique loading conditions, when the remaining tooth structure was smal, the prosthesis was prone to have dental neck fracture. Fiber posts played a protective role in the tooth root, but the clinical probability of failure increased. The fracture mode was changed with the increase of residual tooth amount, transferring from the neck edge to the root. These results demonstrate that we must retain more tooth tissue from the crown in the restoration of residual root with fiber post-core crown.