Effect of surface treatments on fracture resistance of root filled teeth with bonded fibre posts

Background/Aim: This study examined the effect of several dentin surface treatments on fracture resistance of root filled teeth containing bonded fibre posts. Material and methods: The roots of 84 single-canal premolars were instrumented, filled with gutta-percha and randomly divided into seven groups. The coronal 9 mm of gutta-percha was removed to create a post space. In the experimental groups, canals were irrigated with distilled water, 37% phosphoric acid, 5% sodium hypochlorite, 17% EDTA, 5% sodium hypochlorite followed by 17% EDTA or 5% sodium hypochlorite followed by 10% ascorbic acid. Fibre posts were cemented using Panavia F2.0 resin cement, and the specimens were mounted in acrylic resin blocks. Following 1-week storage in an incubator, specimens were thermocycled and their fracture resistance was determined using a universal testing machine. Data were analysed using the Kruskal-Wallis test. Results: Mean fracture resistance values ranged from 465.8 N in specimens treated with sodium hypochlorite and ascorbic acid to 739.1 N for those treated with sodium hypochlorite only. However, differences in fracture resistance were not statistically significant (P = 0.114). Conclusions: None of the surface treatments improved vertical fracture resistance of root filled teeth containing bonded fibre posts.