The Combined Therapy of Teriparatide and Raloxifene Improves Osseointegration of Dental Implants in the Osteoporotic Rabbit Model

Abstract

Purpose: To evaluate the efficacy of combined therapy of teriparatide and raloxifene on the osseointegration of titanium dental implants in a rabbit model of osteoporotic bone. Materials and Methods: Sixty female rabbits were randomly divided into six groups. The sham ovariectomy group (control) consisted of animals that received no medication. Animals in the ovariectomy group (OVX) underwent ovariectomy and received no medication. The combined group consisted of ovariectomized animals that received combined teriparatide (10 mg/kg) for 12 weeks and raloxifene (10 mg/kg) for 12 weeks. The sequential group (SEQ) consisted of ovariectomized animals that received teriparatide (10 mg/kg) for the first 6 weeks and raloxifene therapy (10 mg/kg) for the following 6 weeks sequentially. The parathormone (PTH) and raloxifene (RAL) groups consisted of ovariectomized animals that received only teriparatide (10 mg/kg) for 12 weeks or raloxifene (10 mg/kg) for 12 weeks, respectively. Dental implants (Bilimplant) were placed in the proximal metaphysis of both tibias in all rabbits. Histomorphometric and microCT studies were performed on the specimens obtained from the right tibia bone. Removal torque (RTQ) and implant stability quotient (ISQ) tests were performed on the specimens obtained from the left tibia bone. The results were compared and evaluated statistically. Results: RTQ analysis revealed a statistically significant difference between the mean values of the combined group (93.01 ± 27.19 Ncm) and the OVX group (49.6 ± 12.5 Ncm) (P =.015). The highest mean T0 (implantation day) value was obtained in the control group (67.1 ± 3.4 Ncm), and the lowest mean value was obtained in the OVX group (61.4 ± 3.8 Ncm). The highest T1 mean (3 months after implantation) was obtained by the combined group (76.6 ± 3.8 Ncm), and the lowest mean was obtained by the OVX group (68.9 ± 6.2 Ncm). Histomorphometric analyses showed that the mean percentage of bone-to-implant contact (BIC%) of the combined group (51.2%) was significantly higher than that of the OVX group (28.6%) (P =.006). In the microCT examinations, it was found that the mean BIC% value of the combined group (41.1%) was significantly higher than that of the OVX group (24.1%) (P <.001). Conclusions: According to the results of the current study, combined therapy of teriparatide and raloxifene improves the BIC and osseointegration of titanium dental implants in osteoporotic bone compared with sequential or independent therapy with these agents.