Abstract
Background. Peri-implantitis remains a clinically relevant complication characterized by soft tissue inflammation and progressive bone loss. Existing classification systems vary in their emphasis on clinical severity or defect morphology and seldom provide operational, treatment-linked guidance—particularly for apical disease.
Methods. We conducted a structured critical review of PubMed, Scopus, and Web of Science for studies published in English from January 1990 to December 2023 (last search: December 31, 2023). Full search strategies are reported in Supplementary file 1. Grey literature and conference abstracts were excluded a priori. Two reviewers independently screened records in consensus; a PRISMA-style flow diagram summarizes the selection process. Using a predefined rubric (domains covered, anchors, required inputs, treatment linkage, validation/reliability), we synthesized ten published classification systems (2004–2019) and complemented them with one proposed framework.
Results. Across systems, recurrent gaps included limited integration of clinical parameters with radiographic morphology, inconsistent coverage of implant apical lesions (IALs), and sparse, non-graded treatment guidance. We therefore introduce a three-dimensional framework that classifies lesions as crestal, apical (IAL), or lateral, each with severity strata and operational thresholds (radiographic bone loss relative to functional implant length:<25%, 25–50%,>50%). A standardized measurement protocol is specified (paralleling periapical radiographs as default; selective cone beam computed tomography (CBCT) for suspected buccal/facial dehiscence or equivocal lateral defects), with rules for cases lacking baseline radiographs. A one-page decision algorithm links categories to management options whose strength of recommendation follows the EFP 2023 S3 guideline; laser use is presented as an adjunct where evidence is mixed. Three clinical vignettes illustrate how the framework informs treatment planning. Plans for inter-rater reliability testing are outlined.
Conclusion. This review consolidates and contrasts existing systems and offers an implementable, consensus-aligned framework that unifies morphology, severity, and apical disease with transparent, evidence-graded treatment pathways. Prospective validation and reliability studies are warranted.