Experimental study of regenerative processes in the periodontium in response to photodynamic therapy in combination with various photosensitizers

Objective. To evaluate the regenerative potential of photodynamic therapy using hypericin-based gels at different concentrations (0.1%, 0.5%, 1%) compared to Fotoditazin and a placebo gel in an experimental periodontitis model. Materials and methods. The experiment was conducted on 40 male Wistar rats with modeled periodontitis. The animals were divided into 5 groups depending on the photosensitizer applied. On day 7, histological and histomorphometric examination of the periodontal soft and hard tissues was performed, assessing the inflammatory infiltrate, angiogenesis, and epithelization. Results. The use of hypericin gels at concentrations of 0.5% and 1% led to a significant (p<0.01) increase in angiogenesis and epithelization scores (2 points on the semi-quantitative scale) compared to the other groups. A significant predominance of histiocytes and fibroblasts, along with a decrease in the numerical density of lymphocytes, was revealed in these groups. No significant effect on bone tissue parameters was detected on day 7. Conclusion. Hypericin-based gels at concentrations of 0.5% and 1% showed a significant advantage in stimulating the regeneration of periodontal soft tissues, confirming their promise for further preclinical and clinical studies.