Expression of osteogenic markers after administration of selective estrogen receptor modulators during implant placement in the osteoporotic rat maxilla.

Purpose: This study examined the effects of raloxifene during bone formation around the dental implant in the ovariectomy-induced osteoporotic rat maxilla.

Methods: Fifty-four female 10-week-old Sprague-Dawley rats were divided into three groups (n = 18 each); sham-operated (control), ovariectomized (OVX), and ovariectomized and raloxifene-administered (RAL). Eight weeks after ovariectomy, both upper first molars were extracted, and implants were placed 4 weeks post-extraction. The RAL group was given 1 mg/kg of raloxifene per day while the other groups received a vehicle. Six rats in each group were sacrificed at days 4, 7, and 14 and submitted for quantitative reverse transcription polymerase chain reaction and immunohistochemical staining, for evaluation of osteogenic genes expressions.

Results: The alkaline phosphatase expression was upregulated in the RAL group compared to the OVX group at day 4. The osteocalcin expression was significantly higher between the RAL group and the OVX group at day 7. Immunohistochemical staining revealed increased expression during the initial bone-forming process and indicated more active bone formation in the RAL group than in the OVX group.

Conclusion: Raloxifene administration enhanced the osteogenic genes and proteins expression in the bone around the implant. Further studies are required to establish the long-term clinical effects of raloxifene administration.