Biocompatibility of Ionomeric Cements Modified by Red Propolis: A Morphological and Immunohistochemical Analysis.

Purpose: To evaluate the biocompatibility in rat subcutaneous tissue of conventional orthodontic cements, Riva (R) and Meron (M), modified by the addition of ethanolic extract of red propolis (EERP), at different concentrations and time intervals. Materials and Methods: One hundred eight male adult Wistar rats were used, distributed in nine groups of cements with added EERP at the concentrations used (C-control, MC, M10, M25, M50, RC, R10, R25, and R50). The rats were sacrificed after 3 time intervals (7, 15, and 30 days). Histological and immunohistochemical analyses were performed. The findings were statistically analyzed using the Kruskal-Wallis test followed by Dunn's test (p < 0.05). Results: The highest concentrations led to a higher level of inflammation at the initial times (p < 0.05), but without differences after 30 days. In terms of collagen, there was less collagenization at the initial times in comparison with the control group C. However, over time, the addition of propolis resulted in healing compatible with that of group C. The level of CD68 immunostaining was statistically significantly higher in the groups with the highest concentrations (R50 and M50) (p = 0.001). Conclusion: Orthodontic cements with the addition of EERP were found to be biocompatible in rat subcutaneous tissue. Riva cement with the addition of 50% EERP showed the highest tissue inflammation, but with satisfactory tissue repair.