Osseointegration of Nitrogen-Containing Bisphosphonate Coatings on Dental Implants: An Experimental Pilot Study

Abstract

To compare the osseointegration properties of two different types of nitrogen-containing bisphosphonate (N-BP)-coated dental implants in an experimental in vivo sheep model. In total, eight sheep were divided into two groups receiving implants at two time points. Each animal received four types of implants, AddBIO STL implants coated with Zoledronate (Zol) and AddBIO STL implants coated with Ibandronate and Pamidronate (IbaPam) as test groups and uncoated AddBIO STL implants (UC) and Straumann original SLA implants (SSLA) as controls. Implants were placed in the metatarsus bilaterally, and healing times were either 10 or 28 days. Implant stability quotient (ISQ) was measured at baseline and at euthanasia. Removal torque (RT) was assessed post-mortem, followed by histomorphometric analysis to evaluate bone-to-implant contact (BIC) and bone area (BA). The differences between implants were evaluated using paired t-tests. The significance level was set at p value < 0.05 After 10 days, Zol implants presented significantly higher RT (Ncm mean ± SD) values 26.0 (± 18.0) than IbaPam implants 8.3 (± 14.9) (p = 0.011). SSLA implants demonstrated significantly higher RT values 34.6 (± 22.2) than Zol and IbaPam-coated implants (p = 0.048) and Zol-coated implants showed significantly higher RT values than UC implants 12.0 (± 7.6) than UC implants (p = 0.015). No significant differences in RT were detected at 28 days. No differences were observed among the groups regarding ISQ, BIC, or BA at either time point. Zoledronate-coated implants exhibited enhanced early mechanical stability compared to ibandronate/pamidronate-coated implants. However, this advantage was eradicated after 28 days, suggesting that the early anabolic effect of zoledronate may be time-limited.