Effect of Estrogen Replacement and Calcitonin Therapies on Bone Around Titanium Implants Placed in Ovariectomized Rats: A Histometric Study

Purpose: The aim of the present study was to evaluate whether hormone replacement therapy (HRT) and calcitonin (CT) administration could influence bone healing around implants placed in ovariectomized (OVX) rats. Materials and Methods: One screw-type titanium implant was placed bilaterally in OVX rats. The animals were assigned to one of the following groups: group 1 (n = 15), sham surgeries; group 2 (n = 15), OVX rats; group 3 (n = 14), OVX rats administered CT 4 days/week (16 IU/kg); group 4 (n = 14), OVX rats administered 17 estradiol daily (20 µg/kg). After 60 days, the animals were sacrificed and undecalcified sections obtained. Bone-to-implant contact (BIC) and bone area (BA) around the implants were determined separately for the cortical (zone A) and cancellous (zone B) bone areas. Results: In zone A, intergroup analysis did not reveal a significant difference regarding BIC. In contrast, the HRT group (group 4) presented greater BA than groups 2 and 3 (P .05). Data from zone B revealed that HRT eliminated the negative effect of the ovariectomy on BIC and BA (P .05), while CT had no effect (P > .05). Discussion: It was the first study to evaluate and demonstrate the impact of HRT and CT on bone around titanium implants in an estrogen-deficient model. Conclusion: Within the limits of the present study, it may be concluded that HRT may prevent the influence that estrogen deficiency exerts on bone healing around titanium implants.