An in vitro study of resistance to vertical fracture in restored teeth of four types of post and core systems

Background and Objective: Endodontically treated teeth with extensive loss of coronal structure can be restored with various post systems. Choosing a right type of post will affect the life of the final restoration. The aim of study was to investigate the fracture resistance of endodontically-treated teeth restored using a suggestive and three conventional post systems. Subjects and Methods: Forty extracted and endodontically treated premolars were decoronated 1 mm coronal to CEJ. the teeth were randomly divided into four restorative groups: Group 1, cast post and core; 2, fiber post and composite core; 3, suggestive stainless steel post and composite core; 4, titanium post and composite core. In all groups, posts were cemented with a resin cement (Panavia F). Each root was embedded in an acrylic resin block and loaded vertically in a universal testing machine at a crosshead speed of 0.5 mm/minute until fracture. The data were recorded and analyzed using one-way ANOVA and Tukey tests. Results: The teeth restored with cast post and core demonstrated fracture resistance (162 N) significantly higher than other groups (P<0.001). The fracture resistance in fiber glass post group (133 N) was significantly higher than that in stainless steel and titanium post groups (P<0.001). The difference of fracture resistance between stainless steel post group (102 N) and titanium post group (90 N) was not significant (P=0.28).        Conclusion: The results of study indicated that endodontically treated premolars restored with cast or fiber glass post systems are more resistant to fracture compared to stainless steel and titanium posts.