Knee Loading Promotes Osteointegration In Osteoprosis Rats

Objective:To investigate whether mechanical loadings can promote osteointegration for dental implant.Methods:Twenty four female Sprague Dawley rats (12 weeks of age) were randomly assigned to 4 groups: sham operated control group (sham), knee loading treated sham operated group (sham+loading), ovariectomized group (OVX), and knee loading treated ovariectomized group (OVX+ loading) (n=6 for each group). Four weeks after ovariectomy or sham operation, these rats received the secondary surgical intervention to insert the titanium implant (1.5 mm in diameter, 4.5 mm in length) into the bilateral femoral diaphysis. Knee loading was applied from the second postoperative day after implantation. The loading frequency was 10 Hz, and the loading force was 5 N.Loadings were applied for 6 min per day for five consecutive days per week on bilateral knee joint for 4 weeks. The animals' bone mineral density (BMD) and bone mineral content (BMC) were measured by pDEXA before surgery and sacrifice. The femora then were evaluated by mechanical test.Results:Images withpDEXA revealed that BMD and BMC in the loaded OVX group weresignificantly increased compared with OVX group (both p<0.001). Mechanical test showed that maximum pullout force of the femora weresignificantly increased by knee loading (p<0.001). Conclusion: Collectively, this study demonstrated that knee loading was capable of accelerating osteointegration throughout the implant in the femoral midshaft in osteoporosis SD rats.Mechanical loading could become a potential therapeutic modality for dental implants in osteoporosis patients.