Effects of metformin on bone healing around titanium implants inserted in non-diabetic rats.

OBJECTIVE:To evaluate the effects of metformin on bone healing around titanium implants inserted in non-diabetic rats. METHODS:Twenty Wistar rats were randomly assigned to one of the following groups: control group (n = 10): rats without metformin treatment; MT group (n = 10): rats treated with metformin (40 mg/kg/day by gavage). At thirty days after implant placement, animals were euthanized. Histometric measurements of bone-to-implant contact (BIC) and bone area (BA), in addition to immunohistochemical analysis of the number of cells stained for RANKL and OPG, were assessed in the cortical and medullary areas around implants. RESULTS:The percentages of BIC and BA in the cortical bone were significantly lower in the MT group than in the control group (P < 0.05). Furthermore, the medullary bone around the implants inserted in the metformin-treated animals exhibited an increased number of RANKL-stained cells than that around the implants inserted in the control animals (P < 0.05). CONCLUSIONS:Metformin negatively affected osseointegration by reducing the percentages of BIC and BA and increasing the expression of RANKL around titanium implants inserted in non-diabetic rats.