Resistenza alla frattura di pilastri protesici ricostruiti

The aim of this study was to investigate the behaviour of posts with a low elastic modulus and their splinting effect in fracture resistance test when placed in the root of maxillary central incisors. 80 extracted human maxillary central incisors were endodontically treated and equally dived into 2 groups (test and control). The coronal portion of each tooth was sectioned at different height. In the Group Test (GT) the teeth were restored with carbon fiber posts building up composite cores. In the Group Control (GC) the teeth were restored without post building up composite cores. All samples were fully covered by a non precious alloy cast crown. Each sample was embedded in acrylic resin with a layer of polyvinyl siloxane covering the roots before a compressive load was applied by a universal load testing machine. The mean failure loads were 153,4-358,0 N and 87,0- 196,1 N, for GT and GC respectively. In both groups, fracture resistance to loading test increased as splint length increased. The splint length and the posts with a low elastic modulus improved the strength of the root canal treated maxillary central incisors. The splint length should be at least 2 mm (CUT-OFF levels) to obtain a significant decrease of fracture risk.