How hot is too hot? A bioheat fea of warm obturation in simulated internal resorption with and without periodontal blood flow.

BACKGROUND: This study aimed to assess the impact of different thermoplastic gutta-percha obturation techniques on periradicular tissue temperature changes in maxillary central incisors with simulated internal resorption cavities using finite element analysis (FEA). METHODS: A human maxillary central incisor extracted for periodontal reasons was scanned using a micro-computed tomography device (SCANCO Medical AG, Zurich, Switzerland). Internal root resorptions were designed in the coronal, middle, and apical regions on the solid model using SolidWorks software (SolidWorks Corp., Waltham, MA, USA). The resorption areas were filled using two different thermoplastic gutta-percha techniques: continuous wave condensation (CWC) followed by backfill (BF) techniques, carrier-based gutta-percha (CBG) techniques. The models were also classified based on the presence or absence of simplified blood-flow layer (100 μm) representing perfusion in the periodontal ligament and then transferred to ANSYS software (Canonsburg, PA, USA) for FEA. Consequently, 16 different tooth models were created. RESULTS: Higher temperature values were observed in the apical resorption of the apical third region compared to other regions for both obturation techniques. The CWC + BF technique resulted in higher temperatures and longer durations above the critical threshold of 47 °C compared to the CBG technique. Simulated blood flow reduced PDL and bone temperatures in all models. CONCLUSION: Under these modeled conditions, the CBG technique induced less periodontal heating than CWC + BF, while apical resorption presented the greatest thermal risk. Experimental validation and advanced bioheat perfusion modeling are required before clinical extrapolation.