The present case series evaluated implant survival and changes in bleeding on probing (BOP), probing depths, marginal tissue levels (recession), and bone levels following regenerative treatment of implants with advanced peri-implantitis. Forty-six implants with advanced peri-implantitis in 38 patients were treated with a regenerative protocol and evaluated for the above parameters at the final follow-up 3 to 15 years later. Patients returned every 2 to 3 months for maintenance and at the final evaluation. Measurements were made and compared to those recorded preoperatively. No implant was lost, BOP was reduced to 0 on all but 4 implants, the mean reduction in pocket depth was 6.7 mm, and the average soft tissue marginal position was 0.9 mm coronal to presurgical levels. Bone level changes showed a mean gain of 3.6 mm (radiographically) and 6.8 mm (bone sounding). These results appear to indicate that an implant with > 50% bone loss caused by peri-implantitis can successfully be treated and retained using a specific regenerative technique.