Evaluation of the neurotoxicity of a bioceramic-based root canal filling paste placed on the sciatic nerve in nutritionally supplemented rats: a histopathologic study

The biocompatibility of root canal filling materials and their potential effects on surrounding tissues in endodontic treatments are critical for treatment success and safety. Although bioceramic-based root canal sealers are distinguished by their high biocompatibility and low cytotoxicity, their neurotoxic effects on nerve tissues have not been fully understood. This study aims to evaluate the neurotoxicity potential of AH Plus® Bioceramic Sealer, a bioceramic-based root canal sealer, in combination with the Stemregen® nutritional supplement, which supports stem cell mobilization. The study seeks to provide new insights into strategies that could mitigate the potential toxic effects of bioceramic materials on peripheral nerve tissues. In the study, 48 adult male Sprague Dawley rats were used. The subjects were randomly divided into four groups: (1) control group, (2) nutritional supplement group, (3) bioceramic group, and (4) bioceramic + nutritional supplement group. Bioceramic-based root canal sealer was surgically applied to the right sciatic nerve of the rats. Stemregen® nutritional supplement was administered daily via oral gavage for 15 days. Histopathological evaluation was conducted to assess parameters such as myelin degeneration, axon degeneration, epineurium degeneration, fibrosis, thickening of the epineurium and perineurium, lymphocyte infiltration, fibrocyte density, vacuolization, and edema. Data obtained from the study were analyzed statistically. In the bioceramic and bioceramic + nutritional supplement groups, findings indicating neurotoxicity, such as myelin, axon, and epineurium degeneration; epineurium thickening; fibrosis; thickening of the epineurium and perineurium; lymphocyte infiltration; fibrocyte density; vacuolization; and edema, were significantly increased compared to the other groups. However, the Stemregen® supplement partially reduced these neurotoxic effects, showing lower levels in the specified parameters. The application of Stemregen® was found to have the potential to reduce the neurotoxic effects caused by bioceramic-based root canal sealers. This finding suggests that natural compounds supporting stem cell mobilization may be utilized to prevent and repair nerve damage in endodontic applications. However, more comprehensive and long-term studies are needed to confirm this effect in clinical settings.