INFLUENCE OF POST LENGTH ON THE BOND STRENGTH OF FIBER POST AND FRACTURE RESISTANCE OF ENDODONTICALLY TREATED

MastersObjective: The aims of this study were to investigate the effect of different prefabricated fiber-reinforced post lengths on the post bond strength and fracture resistance of endodontically treated teeth. Material and Methods: Ninty extrcted single rooted premolars were selected. Eighty of them were subjected to root canl therapy and were left unobturated. Specimens were assigned to two experimental groups (40 teeth each) to be subjected to post bond strength test and fracture resistance test. Each group was further divided into two groups (20 teeth each) according to the post type: prefabricated glass-fiber post and prefabricated titanium post. Posts were cemented using resin cement at two lengths: 5mm and 10mm into their respective canals after post space preparation. A control group of 10 teeth , without post placement, was subjected only to fracture resistance test. For fracture resistance test; the specimens were further subjected to cores buildup using composite resin, followed by cementation of zirconum oxide copings. Both tests were then carried out using universal testing machine to calculate the maximum force required to dislodge the post for bond strength test and the maximum load required to fracture the spacimens for the fracture resistance test. Analysis of variance and Tukey¡¦s Post-Hoc statistical tests were used at significance level 5%. Results: The results showed for glass fiber posts there were no significant differences between 5mm and 10mm post lengths for both bond strength test and fracture resistance test, (p=.840) and (p=.985), respectively. Teeth restored with 10mm titanium posts had no significant difference in fracture resistance compared to the teeth restored with 5mm titanium post. However, the long titanium posts had significantly superior retention compared to short titanium post (p=.001). Glass-fiber post had more favorable restorable mode of tooth fracture when compared to titanium post. Conclusion: Within the limitations of this in vitro study, the following conclusions can be drawn: „X Teeth restored with short (5mm) and long (10mm) glass-fiber post did not differ significantly in terms of post bond strength and fracture resistance, yet, the 10 mm glass-fiber post offer more favorable mode of fracture. „X Teeth restored with short (5mm) glass-fiber post had significantly higher fracture resistance and post bond strength compared to teeth restored with short (5mm) titanium post. „X Teeth restored with longer (10mm) titanium post had no significant difference in fracture resistance compared to the teeth restored with short (5mm) titanium post , but had significantly superior post bond strength compared to short titanium post. „X Glass-fiber post had more favorable restorable mode of fracture compared to titanium post. „X A parallel-sided glass-fiber post with 5mm length luted with adhesive resin cement may offer acceptable performance in relation to post bond strength and fracture resistance