This case series presents clinical outcomes on reentry using regenerative submerged and nonsubmerged approaches in peri-implant defects; pre- and posttreatment assessments of nine implants in six patients are presented. A mean bone fill value of 91.3% with a 4.88-mm mean bone gain was obtained. Neither approach led to additional bone loss or required additional bone augmentation procedures. Strict methods of implant surface decontamination and detoxification were used on all patients, regardless of implant surface characteristics. The regenerative procedure was effective in the treatment of moderate to advanced peri-implantitis lesions without compromising the previous fixed implant-supported prostheses. These preliminary results are reasonably encouraging in that all cases showed bone gains. Nevertheless, caution must be exercised when determining reosseointegration, because it is not possible to ascertain it in clinical practice.