Fracture Resistance of Cast Metal and Zirconia Posts on Endodontically Treated Teeth: An in Vitro Study

Background: ETT are widely considered to be more susceptible to fracture than vital teeth and require specialized restorative treatment. The aim of this study was to estimate and compare the fracture resistance (FR) of Endodontically treated teeth (ETT) restored with cast metal posts (CMP) and zirconia posts (ZP) with Universal Testing Machine (UTM). Methods and Results: A total of 60 intact canines extracted for periodontal reasons were selected for the present study. The tooth samples were randomly divided into 2 groups based on the post type used for restoration. Group 1 tooth samples (n=30) were restored with CMP. Group 2 tooth samples (n-30) were restored with ZP. All the samples were subjected to compressive load using a UTM at a cross-head speed of 0.5mm/min on the palatal slope at an angle of 135° to the long axis of the tooth. The maximum load necessary to fracture for each specimen was measured in Newtons (N). The results obtained showed that the difference in FR means between CMP and ZP was statistically significant (P<0.0001). Conclusion: The FR of ZP was found to be significantly higher than those of CMP. The FR analysis with UTM is the only method that enables us to estimate the differences between the ETT restored with CMP and ZP.