In-Vitro evaluation of fracture resistance of weakened roots restored with fiber posts and tooth-colored materials

In-Vitro evaluation of fracture resistance of weakened roots restored with fiber posts and tooth-colored materials Dr. H. Moosavi* - Dr. F. Maleknejad**- Dr. I. Nasiraee*** * Assistant Professor of Operative Dentistry Dept., Faculty of Dentistry, Mashhad University of Medical Sciences. ** Associate Professor of Operative Dentistry Dept., Faculty of Dentistry, Mashhad University of Medical Sciences. *** Dentist. Background and Aim: Restoration of endodontically-treated anterior teeth with weakened roots requires special attention. The purpose of this investigation was to compare the fracture resistance of experimentally weakened anterior roots reinforced with three different methods using tooth-colored materials. Materials and Methods: Forty human sound maxillary central incisors were used in this in vitro study. The crowns of 30 teeth were removed 2mm above the CEJ. After root-canal therapy, flared canals were simulated. The teeth were filled with D.T. light-post plus resin composite (Clearfil DC Core Automix) in group 1, D.T. light-post plus two accessory posts (Reforpin+Panavia F 2.0) in group 2 and D.T. light-post plus Panavia F 2.0 in group 3. Access cavities in the fourth (control) group were restored after ideal root-canal therapy. Following cementation of the posts and restoration of the crowns with Clearfil Photo-Core composite, the roots were embedded in acrylic resin blocks, 1 mm below the CEJ. After 24h storage, the samples were loaded in an Instron testing machine with a crosshead speed of 0.5 mm/min at a 45° angle to the long axis of the tooth on the palatal surfaces until failure. The data were analyzed using ANOVA and Tukey test (P=0.05). Results: The lowest (300.17 N) and highest (585.11 N) mean fracture resistance values were observed in the third and fourth groups, respectively (P<0.05). These values were not significantly different between the first, second and third groups. Conclusion: The results showed that Reforpin could be used as an alternative to resin composite for internal reinforcement of weakened roots. Key words: Weakened root - Fracture resistance - Resin composite.