Fracture resistance of endodontically treated maxillary premolars with Mesio-occluso-distal (MOD) cavities supported by horizontal glass fiber posts versus vertical glass fiber posts: An in vitro study

Abstract
Aim: The aim of this study was to assess the fracture resistance of endodontically treated maxillary premolars with mesioocclusodistal (MOD) cavities supported by horizontal glass fiber posts. Methodology: Thirty three extracted maxillary premolars were collected and grouped into three. MOD cavities were prepared and all of them were endodontically treated. Teeth were supported with horizontal glass fiber posts; vertical glass fiber posts and composite restoration alone in the three groups respectively. Fracture resistance assessed using Universal testing machine. Type of fracture was assessed using visual examination. Type of failure was assessed using Stereomicroscope. Results: Highest fracture resistance was shown by samples supported by horizontal fiber post (Group C). Group B had higher chances of Type 1 failure (Adhesive failure between post and luting cement) compared to other groups. Group A had higher chances of Type 4 failure (Cohesive failure) and Group C had higher chances of Type 5 failures (Mixed type; combination of any two of the above-mentioned types).There was no statistically significant association between groups and fracture mode (repairable and unrepairable). Majority of samples from Group A and Group C underwent repairable fractures. Conclusion: Fracture resistance of horizontal fiber post group was significantly higher compared to the other two groups.