Objective:To study the effects of metformin on marginal bone resorption of implants in patients with type 2 diabetes melli-tus(T2DM)and exercise habit.Methods:63 cases with 73 implants were included.Among them,there were 41 cases(47 implants)without T2DM in group N,10 cases(13 implants)with T2DM and without exercise habit in group M,12 cases(12 implants)with T2DM and exercise habit in the MR group.The patients were followed up at 6 months,1 and 2 years after implantation.The marginal bone loss(MBL).Implantation success rate and peri-implantitis incidence rate were compared among the groups.Results:The bone resorption of the proximal and median margins of the long-term bone level of the implants in the N and MR groups were significantly lower than that in the M group(P=0.001 and P=0.000 5,respectively).The implant success rates of group N,MR and M were 95.74％,100％and 76.92％,respectively.The incidence of peri-implantitis of the three groups was 2.13％,0 and 15.38％,respec-tively.Conclusion:Metformin is more effective in the improvement of the long-term marginal bone resorption of implants,increase the success rate of implants,and reduce the incidence of peri-implantitis in patients with T2DM and exercise habit in the mandibular first molar area.