The Effect Of Immediate Loading On Peri-implant Bone Maintenance And Bone Healing

Objective:Immediate loading, as a treatment for repairing missing teeth in short cycles, hasbeen applied in clinical practice. Many researchers focus their attention on its clinicalprognosis. Maintenance of the bone height around implant and improvement of bone-to-implant contact have been concerned all around. However, the mechanism of boneformation and remodeling around implant is not very clear. The studies showed thatthe formation and remodeling of bone are closely related to mechanical loading. Thestudy aimed to provide theoretical and practical evidence for clinical and researchapplication by studying buccal marginal bone loss (MBL), bone-to-implant contact(BIC) and new bone formation on peri-implant bone and discuss the role ofmechanical loading in bone formation and remodeling.Methods:First to fourth bilateral mandibular premolar teeth of ten Beagle canines wereextracted. Three implants were inserted in each side of the mandible after3monthshealing. One side of implants were loaded immediately which metal superstructurewere cemented within48hours, while the other side of implants were unloaded ascontrol group (CG). The height of buccal bone around implants at0(baseline),1,3,6,8,12weeks time points after implant placement were measured by using thetechnique of Spiral CT scanning and3D reconstruction. The influence of mechanicalloading on MBL was evaluated. Bone to implant contact(BIC) and new bone volumefraction (NBVF) were studied at1,3,6,12weeks post-surgery by the technique ofthin ground sections and the effect of immediate loading on bone healing wasevaluated.Results:According to the measurement by Spiral CT, the height of buccal bone decreased at1,3,6and8w when compared to baseline at both immediate loadinggroup(ILG)and CG, whereas there was no significant difference among the differenttime points. The heights of buccal bone at ILG were observed to be significantlyhigher at1,3,8and12w when compared to CG. The absorption rate of buccal boneincreased when times went by, but there was no significant difference among thedifferent time points at both groups. No significant difference of absorption rate ofbuccal bone showed at ILG when compared to CG.Thin ground sections studiesindicated no significant difference of BIC and NBVF of ILG at each time pointswhen compared to CG.Conclusion:It was concluded that immediate loading would neither have effect on buccalbone resorption, nor peri-implant bone healing.