This retrospective study of 176 sites in advanced periodontitis found similar long-term survival and success for periodontal regeneration (PR) and implants, but substantially more complications with implants, mainly peri-implantitis. Site-level risk strongly influenced PR outcomes: one-wall defects, furcation involvement, and higher Periodontal Risk Scores (PRS2–3) greatly increased tooth loss. Mean costs were lower for PR ($1,268) than implants ($2,170), and overall implants cost about $239 per extra year of survival gained. Implants became more cost-effective only for teeth with poor prognosis or furcation involvement, whereas well‑prognosis teeth (PRS1 without furcation) were more cost-effective to preserve with PR.