Resistance of teeth with simulated incomplete rhizogenesis with intraradicular post or root canal filling.

AIM The aim of this study was to evaluate the fracture strength (FS) of bovine incisors with simulated incomplete rhizogenesis (IR) after different intraradicular treatments. MATERIALS AND METHODS Incomplete rhizogenesis was simulated by sectioning the crowns and roots of 40 bovine incisors. Root canal preparation was performed and the samples divided into 4 groups (n = 10): GI-negative control with intra-radicular preparation; GII-positive control without intra-radicular preparation; GIII-glass fiber post cemented with resin cement and GIV-root canal obturation with Epiphany/Resilon system. In GIII and GIV, 4.0 mm apical plugs of mineral trioxide aggregate (MTA) were done. The samples were embedded into cylinders with polystyrene resin, and the periodontal ligament was simulated with a medium-viscosity polyether-based impression material (Impregum Soft). The specimens were submitted to compressive fracture strength test (0.5 mm/min at 135° in relation to the long axis of the tooth) in a mechanical testing machine MTS 810. Data were submitted to ANOVA and Tukey's test (α = 0.05). RESULTS GIII produced the highest FS values (p < 0.05). GI and GIV showed similar FS results (p > 0.05) but smaller than GII (p < 0.05). CONCLUSION Glass fiber intraradicular posts provided the FS increase of teeth with simulated incomplete rhizogenesis. Epiphany/Resilon root canal flling with MTA plug did not provide the increase of the fracture strength to teeth with simulated incomplete rhizogenesis. CLINICAL SIGNIFICANCE The fiber post reinforces the root structure of teeth with incomplete rhizogenesis.