Analysis of Cementation in Root Posts Using The Finites Elements

Objectives: The aim of this study was to analyze a non-linear mechanism of the cementation of root posts through the formation of gaps in cement-dentin and cement-post interfaces analyzing the correlation of mechanical test and computational model. Methods: Were selected 15 mandibular pre-molars, to receive root posts Exacto (Angelus®) fixed with Cement-Post (Angelus®). The teeth were cuted in cervical, middle and apical root discs. These discs were molded with silicone and epoxy resin replics was obtained before and after the compression test (220 N-0, 2 mm / min). The replics were analyzed in MEV to observe the gaps formation at the interfaces, with Image Tool program. For statistical analysis of the gaps measures (µm) was used the Wilcoxon test. The dentin discs were photographed and their images obtained from 3D models simulating the compression test using the Finite Elements Method. Results: For gap`s measures between cervical, middle and apical root discs there were statistical diferences (p<0.0001). In the comparison between the gaps in the same interface of the cervical, middle and apical discs before and after the compression test, there was no statistically significant difference (p = 0.4304) and (p = 0.7766), respectively. In cement-post interface there was no gaps in most specimens. In Finite Element Method results there was a low stress concentration in dentin-cement and cement-post interfaces. Conclusion: The difference between mechanical and computational tests was that in computational model was considered perfect adhesion, which does not occur clinically. In future studies must be use a computational interface component to simulate the real interface.