Periodontal health and biofilm-induced gingivitis: a narrative educational review based on the 2017 World Workshop classification

Objectives. To consolidate the diagnostic criteria for periodontal health and biofilm-induced gingivitis according to the 2017 World Workshop (2017WW) classification and to propose a teaching-oriented diagnostic sequence for periodontics education. Material and methods. A narrative literature search was conducted in PubMed and Scopus for articles published up to May 2026 that addressed the 2017WW classification of periodontal health and biofilm-induced gingivitis. Relevant original studies, reviews, and consensus reports were selected and synthesized to provide an educational narrative review of periodontal diagnosis. Thirty-seven articles were selected for the results and discussion. Results. To determine the correct diagnosis, the presence of periodontal pockets, defined as periodontal probing depth (PPD) ≥4 mm, and clinical attachment loss (CAL) should first be assessed to rule out periodontitis. Once periodontitis has been ruled out in the initial diagnostic process, the percentage of sites with bleeding on probing (BOP) should be evaluated. If this percentage is less than 10%, the condition is considered “periodontal health.” Periodontal health can be present in an intact periodontium or in a reduced periodontium. When the percentage of sites with BOP is equal to or greater than 10%, the condition is considered “biofilm-induced gingivitis” in an intact periodontium and in a reduced periodontium not secondary to treated periodontitis, or “biofilm-induced gingival inflammation” when the reduced periodontium is secondary to previously treated periodontitis. Conclusion. This narrative review provides a didactic synthesis that organizes and simplifies the sometimes fragmented literature on the 2017WW classification of periodontal health and biofilm-induced gingivitis, offering clinicians, students, and educators a single reference point for current diagnosis.