| Background: Bone internal fixation material is widely used inorthopedics and dentistry. Successful implantosseointegration mainly depends on extensive bone-to-implantcontact (BIC) and adequate peri-implant bone mass. Asepticloosing, which caused by osteolysis around the implant, is themost common reason of failure of internal fixation. Activationand supplement of osteoclasts outside the bone-implantinterface are related to osteolysis due to the wear particlesor the local inflammatory factors derived by implant. Somediseases caused by alteration of bone metabolism and intrinsicbone quality in pathologies, like osteoporosis characterizedby low bone mass and deteriorated bone micro structure, willfurther impede optimal implant stability. The main reasons forimpaired osseointegration are enhancement of osteoclastic boneresorption and insufficient of osteoblastic bone formation. Sotherapeutic options based on anticatabolic or anabolic drugsare used to improve implant fixation, especially inosteoporotic implant fixation. Bisphosphonates (BPS) represent one of the validanticatabolic compounds, which have been proved to promoteimplant osseointegration in ovariectomized (OVX) animals inorder to improve the therapeutic efficacy and the clinicalservice life of total hip replacement. In the treatment ofosteoporosis, BPS maintain bone mass mainly by restraining theloss of bone mass and bone resorption. Zoledronic acid (ZA),as the third generation of Nitrogen containing bisphosphonatescharacterized by heterocycle, is a bone absorption inhibitorwith the strongest pharmacological activity currently. Itsmain function is to inhibit bone resorption by restraining theactivation of osteoclasts and proliferation of immatureosteoclasts. The main mode of administration of Zoledronic acidis systemic intravenous drip, and also local application, suchas coating, soaking method etc.Clinical efficacy and safety of Zoledronic acid hasbeen confirmed in clinical trials. Intravenous infusion iswidely used in clinical treatment of osteoporosis, and therelevant research on local application is deficient at home andabroad. This study, by surgical removal of bilateral ovariesof female rabbits and establishment of osteoporotic rabbitmodels after menopause, evaluates the influence of local application of zoledronic acid on implant osseointegration andthe stimulative effect of zoledronic acid coating on theimplant bone integration to provide a theoretical basis for itsclinical application.Objective: This study successfully established ovariectomized(OVX) rabbits osteoporosis model with titanium (Ti) implantsinserted in the partial femur to observe and compare the periimplant bone density and bone formation of the HA coatingimplant group with zoledronic acid on surface and of HA coatinggroup without zoledronic acid to explore the effect ofzoledronic acid on the implant osseointegration, and providea theoretical basis of its clinical application.Method:20female rabbits were randomly divided into threegroups: A, B and C. Animals in group B and C received bilateralovariectomy and group A underwent sham operation.12weeksafter surgery, femoral bones of rabbits were examined for bonemineral density(BMD). Then fixed implants in the bilateraldistal femur, group B, which was the control group, receivedHA coated implants; group C received zoledronicacid immobilized HA—implants, which can be called theexperimental group. Animals were killed at3months afterimplantation surgery, produce hard tissue slicings, and use dual energy X-ray to measure bone mineral density and bonemineral content of experimental animals forhistological observation of new bone formation.Results: dual energy X-ray results show: compared with controlgroup, bone mass around the plant of experimental group isimproved obviously, bone density is raised, bone mineralcontent is increased. Histological results showed that: thebone trabecula around implant of experimental group is morethan the control group’s. Although the trabecular bone is thin,but its continuity is good enough. Therefore, new boneformation is advanced, and osseointegration is enhanced.Conclusion:1. The rabbits were ovariectomized and given intramuscularinjection of dexamethasone for12weeks. It can effectivelyestablish the animal model of osteoporosis after menopause.This method has the advantages of simple operation,shortcycle,low cost etc2. The topical application of zoledronic acid can resist thenegative effects of osteoporosis, increase theosseointegration rate, and promote osteointegration ofimplant.3. The results may provide experimental basis for application of internal fixed titanium implant with zoledronic acid inosteoporosis,and it has potential value in clinicalapplication. |
PDF Full Text Request