Purpose: This research was conducted to evaluate the effect of two intrapulpal depth with two different materials on fracture resistance of endo-crowns restoring premolars.
Materials &Methods: 28 sound premolars were assigned to two groups (n=14), Group A (2 mm extension into the pulp chamber), Group B (6 mm extension intrapulpally).then each group is subdivided into two subgroups (n=7) according to the type of the material used Subgroup I(Enamic), Subgroup II(Suprinity). All premolars were decoronated to be 3 mm above the CEJ Proximally. Samples were split into two groups regarding the type of preparation done.After cementation, fracture resistance test was performed. Data was collected and statistically analyzed.
Results: There was a statistically significant difference between samples regarding different depths of preparation extension were the highest value of fracture resistance was in samples with 6 mm extension depth (1617.43 N ) as well as samples regarding the type of the material, where all samples of Vita Suprinity showed higher values of fracture resistance in each depth.
Conclusion: It could be concluded that root canal treated premolars can be restored with endocrowns, moreover, the increase of the preparation depth of the endocrowns are less prone to fracture