Influence of remaining Coronal Tissue Height on Fracture Strength of Over-flared Endodontically Treated Central Incisors Restored with multi post approach

Abstract

Objectives: This study aimed to examine the effect of remaining coronal tissue height on the fracture strength of overfl-ared endodontically treated central incisors restored with multiple prefabricated glass fiber posts, using the multi-post approach Materials and Methods: Forty human central maxillary incisors were used in this study. The samples were categorized into five groups of 8, including four groups based on the height of the remaining coronal tissue (0, 1, 2, and 3 mm) and one entire tooth group. Following endodontic treatment of an overflared canal, the post space depth was 10 mm, and the residual dentin thickness was 1 mm. Two prefabricated glass fiber posts were cemented into the root canal using a multi-post approach.. The static load was applied at 0.5 mm/min and 135 ˚ concerningthe tooth's longitudinal axis until a fracture occurred. One-way ANOVA and the post hoc Tukey’s test were used to analyze the data at a significance level of P<0.05 Results: The maximum fracture strength belonged to intact teeth (control group), while the minimum fracture strength occurred for teeth with coronal tissue height of 1 mm. The differences between the intact teeth group and other groups were significant (P<0.05) as well as between the group with 3 mm coronal tissue height and groups without coronal tissue and 1 mm coronal tissue height. Conclusion: An increase in the height of the remaining coronal tissue (>=3mm) significantly increased the fracture strength of over flared endodontically treated central incisors, following restoration with prefabricated glass fiber posts via multi-post approach.