Comparing the stability of implants coated with nano PLGA-alendronate sodium: an in-vivo study

Considering the effect of bone resorption-inhibiting drugs, such as bisphosphonates, on bone density, the present study evaluated the stability of implants coated with polylactic-co-glycolic acid (PLGA)-alendronate sodium.

Ten healthy Swiss rabbits were selected (mean weight: 3.5 kg). Two titanium implants were inserted in each rabbit's tibia bone, one implant coated with PLGA-alendronate sodium and the other functioning as control. Torque meter equipment measured the amount of torque while inserting the implants. Insertion torque was measured during the initial insertion of the implants, and after 4 weeks, the rabbits were anesthetized again, the implants were exposed, and resistance torques were measured and recorded. Using a trephine bur, all implants and the surrounding bone structure were then removed for histological evaluation. Fourier transform infrared spectroscopy was used to investigate alendronate and PLGA biologically. Data analysis was performed using SPSS.v23 software with a significance level of p < 0.05.

The results showed that the difference between insertion torque and final resistance torque after 4 weeks was statistically significant (p = 0.024). The mean number of osteoclasts and macrophages differed substantially between the experimental and control groups (p < 0.001). The ratio of woven bone to lamellar bone and the number of osteoblasts did not differ significantly between the two groups (p > 0.05).

The use of PLGA-alendronate sodium coating decreased the number of osteoclasts and macrophages and increased the stability of implant anchorage.