الفهرس | Only 14 pages are availabe for public view |
Abstract Restoration of teeth after endodontic treatment is an integral part of restorative practice in dentistry. As these teeth are affected by a higher risk of biomechanical failure compared to vital ones, a plethora of articles have been written in the dental literature regarding the prosthodontic management of endodontically treated teeth. Many of these papers have discussed techniques of fabricating posts and cores, whereas others presented clinical and laboratory data that help to answer questions regarding the best prosthodontic treatment for these teeth. The purpose of this study was to evaluate the influence of Ferrule Design, Post Type and Functional Loading on the Fracture resistance and Coronal Leakage of Endodontically Treated Maxillary Premolars. One hundred intact bifurcated maxillary first premolars were selected for the study. selected teeth were randomly divided into three main groups; two test groups and one control group. Test samples were prepared to receive post, core and coronal coverage and were assigned in two groups (U & N) according to the remaining amount of tooth structure. Teeth of group U (n = 40) were prepared to provide a ferrule of 1.5mm uniform height, while for group N (n = 40) further teeth reduction was performed to provide a ferrule of non-uniform height (1.5mm buccal and palatal, 0.5mm proximal). According to post type, whether ready-made or individually formed FRC post, each test group was divided in 2 equal subgroups (R & I). Control samples, group A (n = 20) were prepared for coronal coverage, no posts were used and the prepared teeth were intact except for endodontic access openings. According to the loading condition, being a crown (C) or a bridge (B) abutment, premolars of the control group and the test subgroups were divided in two equal divisions (n = 10). Polyethylene core formers were used to form standard composite cores, while silicon molds were used to Shape the wax patterns of the suprastructures. All posts and suprastructures were cemented using dual cured composite resin cement. Then the specimens were subjected to thermal cycling and dynamic loading before testing. Half the specimens were tested for fracture strength evaluation in a Universal Testing Machine by the application of an oblique load at an angle of 30º degree to the long axis of the tooth. The other half was assessed for coronal micro-leakage using the linear dye penetration test. Statistical analysis of the results revealed that functional loading, post type and the interaction between the three variables had a statistically significant effect on the fracture resistance, while the ferrule design didn’t influence the results. In terms of coronal leakage, none of the tested variables significantly affected the results. There was a non-statistically significant negative (inverse) correlation between fracture strength and leakage scores. |