A study on the stability of miniscrew on different loading time as orthodontic anchorage

PURPOSE:To evaluate the stability of the miniscrew on different loading time as orthodontic anchorage.METHODS: 2 healthy adult male Beagle dogs were used in this study.48 mini-implants were implanted into the maxilla and mandible of the dogs.The miniscrews were divided into 8 different groups,1 group was loaded 0g as control group and the others were loaded 200g forces as experimental groups.200g forces were loaded on the corresponding mini-implant anchorages immediately after implantation and at the time of 1w,2w,3w,4w,5w and 6w after implantation.The dogs were sacrificed at 12w after implantation.Histological progresses of implant-bone interfaces was examined with light microscope.Blue deposition and contact ratio were calculated and analyzed using SPSS13.0 software package.RESULTS:Fibrous and osseous-integration was noted in the interface,there was no significant difference in bone deposition ratio and bone contact ratio.CONCLUSION: Different force loading time does not affect the stability of the mini-implant anchorage.Supported by Natural Science Foundation of Shanghai Jiao Tong University School of Medicine(757).