Histologic evaluation of new bone in post-extraction sockets induced by melatonin and apigenin: an experimental study in American fox hound dogs

Objective: The aim of this study was to evaluate the effect of topical applications of melatonin and apigenin (4 0,5,7- trihydroxyflavone) on new bone formation in post- extraction sockets after 30, 60 and 90 days. Materials and methods: Six American fox hounds were used in the study, extracting mandibular premolars (P2, P3 and P4) and first molar (M1). Melatonin or apigenin impregnated in collagen sponges were applied at P3, P4 and M1 sites in both hemimandibles; P2 sites were used as control sites. Bone biopsies were taken at 30, 60 and 90 days and stained with hematoxylin- eosin. Results: At 30 days, a higher percentage of immature bone was observed in the control group (58.11 +/- 1.76%) than in the apigenin (34.11 +/- 1.02%) and melatonin groups (24.9 +/- 0.14%) with significant differences between the three groups (P < 0.05). At 60 days, results were significantly better at melatonin sites (10.34 +/-1.09%) than apigenin (19.22 +/- 0.35%) and control sites (36.7 +/- 1.11%) (P < 0.05). At 90 days, immature bone percentages were similar for all groups. New bone formation was higher in melatonin group (79.56 +/-1.9%) than apigenin (68.89 +/- 1.5%) and control group (58.87 +/- 0.12%). Conclusions: Topical applications of either melatonin or apigenin have a potential to accelerate bone tissue in early healing stages; melatonin was seen to have stimulated bone maturation to a greater extent at the 60 days of follow-up.