Abstract

Objective:
The aim of this study was to evaluate and compare the stress distribution in simulated mandibular premolars with an internal resorptive cavity (IRC) and obturated adopting a hybrid technique combining thermoplasticized gutta-percha with two different bioceramic materials – Mineral Trioxide Aggregate (MTA) and Biodentine – using Finite Element Analysis (FEA).
Methods:
Three finite element models of a mandibular premolar with an IRC at the mid-root level were geometrically modelled based on data from previous literature. The simulated teeth were obturated using different materials - thermoplasticized gutta-percha, MTA and Biodentine. The models were discretized using quadratic tetrahedral solid elements, yielding a mesh of 102830 elements and 189280 nodes. Using Ansys 15.0 software ( Ansys Inc., Canonsburg, PA, USA ) a force of 300N was applied at 45° angulation to the long axis of the tooth, on the buccal cusp tip.
Results :
The model obturated with gutta-percha exhibited the highest von mises stress concentration (162.79 MPa), while the Biodentine model showed the lowest (143.37 MPa). All three models demonstrated maximum stress concentration at the cervical region. Stress distribution within the IRC was more homogenous in the MTA and Biodentine models compared to gutta-percha.
Conclusion: Biodentine demonstrated the most favourable biomechanical behaviour, with lower peak stress concentration and more uniform stress distribution than gutta percha and MTA. Calcium silicate- based materials may provide biomechanical advantages when restoring teeth affected by internal resorption.

Key words: finite element analysis, root resorption, gutta-percha