Temperature rise in surrounding tissues during warm vertical compaction in c-shaped root canal systems: a finite element study

Abstract Background: Temperatures above 47°C can cause irreversible damage to the periodontal ligament and surrounding tissues. This study investigated whether a 10°C temperature rise, potentially harmful to the vascular structure of the periodontal ligament, occurs during the continuous wave compaction technique. It also assessed the effects of C-shaped root canal anatomy and device temperature settings on thermal transmission. Methods: Finite element analysis was used to simulate C-shaped mandibular molars, including periodontal ligament tissues with assumed perfusion rates equal to those in human gingiva. Temperature changes were recorded during warm vertical compaction and backfill phases. The temperature at the periodontal ligament adjacent to the root surface was continuously monitored, and the highest values and their timing were documented. Results: High-temperature settings (250°C for down-pack, 200°C for backfill) led to peak periodontal ligament temperatures of 66.67°C and 53.31°C, respectively. In contrast, lower settings (90°C and 100°C) kept periodontal ligament temperatures below the critical threshold, with maximum values of 44.37°C and 43.12°C. The greatest temperature rise occurred during the early seconds of the down-pack phase. Conclusions: Excessive heat generated during warm obturation techniques can elevate periodontal ligament temperature beyond safe limits, especially in anatomically complex roots. Lower temperature settings are recommended to minimize the risk of thermal injury to periradicular tissues.