Research On The Influence Of Submerged And Nonsubmerged Implant Denture On The Expression Of Osteopontin In The Process Of Implant-Bone Interface Remodeling In Beagle Dogs

With the economic development and intensifying society aging, more and more patients tend to choose implant denture as the main approach for the treatment of the dentition defect or edentulous jaws. The loading implant must be supported by the implant-bone interface, and bite force which effects the dynamic remodeling of interface is conducted from the implant denture to the implant-bone interface. Traditional submerged implant denture has been used widely in clinical. However, as a modified form, it takes only one operation for non-submerged implant denture, and the certain functional stimulus of such an implant is regarded to be good for the growth and remodeling of the surrounding bone. Therefore, the application of it has been increasing in the past few years. Reports regarding the difference between submerged and non-submerged implants were hardly available.Osteopontin(OPN) is a major extracellular non-collagen matrix protein in the bone and associated with mineralization and resorption of bone tissue. It had been reported that the expression of osteopotin could be promoted by the stress caused by the loading of immediate implant, though the exact mechanism remained unknown.But the mechanism is not clear. Hence, the present study was to investigate the dynamic change of osteopotin at the implant-bone interface after the loading of implant denture and the molecular mechanism of the effect of OPN on the remodeling of the interface by comparing the submerged and non-submerged implant directly.ObjectiveTo study the expression of osteopontin(OPN) in the process of implant-bone interface remodeling after loading of submerged and nonsubmerged implant dentures.Methods8 adult beagle dogs were used to build the animal model. Submerged and nonsubmerged implants were implanted into the bilateral mandible. Fixed metal full crown was used to carry out the submerged and nonsubmerged implant denture.The beagle dogs were sacrificed by steps after loading.Immunohistochemistry was used to observe the dynamic expression of osteopontin in the implant-bone interface.Results1. A weakly positive expression of OPN was found at the implant-bone interface in control groups (not repair) . There was no significant difference at each time point and no regulation.2. The OPN in the implant-bone interface in submerged experimental groups was significantly higher than that in control groups. There was regulation.3. The OPN in the implant-bone interface in nonsubmerged experimental groups was significantly higher than that in control groups. There was regulation.4. The grey level of OPN which was 93.59±1.07 in the implant-interface in submerged experimental groups increased after loading of 2 weeks,and reached peak at 124.96±5.19 after 8 weeks.Then it dropped down to 87.26±0.61 and was not significantly different from the normal level 83.29 after 12 weeks.5. The grey level of OPN which was 93.37±1.13 in the implant-interface in nonsubmerged experimental groups increased after loading of 2 weeks,and reached peak at 126.91±0.58 after8 weeks.Then it dropped down to 84.13±0.35 and was not significantly different from 84.15 the normal level at 12 weeks. 6. No significant difference was found in the expression of OPN between the submerged and non-submerged experimental groups at each time spot in this study.ConclusionThe expression of OPN at the implant-bone interface could be stimulated by the mechanical loading which was conducted from implant to the interface in both the submerged and non-submerged implants. Meanwhile, the expression of OPN which showed an effect on the remodeling of the interface changed according to the loading period. As to the effect of the remodeling of the interface, no significant difference was found between the submerged and non-submerged implant groups.