Assessment of heat transfer to periodontal tissues and stress distribution in a tooth with simulated internal resorption cavities at different root levels using two thermoplasticized obturation systems – A finite element analysis study

Aim: This study aimed to evaluate the heat transfer to periodontal tissues and stress distribution within simulated roots with internal root resorption cavities at three different levels using two thermoplasticized obturation systems using finite element analysis. Methods: Maxillary central incisors with single canals were chosen for the construction of the simulation and geometric models. Cone beam computed tomography scan of a skull was used to model the periodontal ligament and alveolar bone. Construction of the simulating model and geometric model and conversion to finite element model was conducted with three-dimensional tetrahedral elements at three different levels. These three models were duplicated for stress distribution and heat transfer analysis during the down packing and backfilling procedure to periodontal tissues. A simulation of root canal preparation and obturation procedures was conducted using ANSYS 19.2 software, and static structural, steady-state thermal, and transient analysis were carried out. Results: The total average stress was the highest when the resorption cavity was in the middle third (1.72 Mpa) for the calamus dual obturation system. The total average temperature observed was the highest when the resorption cavity was in the middle third (37.4°C) for the elements free obturation system and in the apical third (53.73°C) for the calamus dual obturation system. Conclusion: It was observed that between the two systems, elements free obturation system led to lower heat transfer and heat flux during the down packing procedure in comparison to the calamus dual obturation system, and the remaining dentin thickness was directly proportional to the amount of heat transferred to the surrounding tissues.