A patient presents with bleeding on probing in approximately 85% of sites, probing depths of 2-3 mm throughout, and beautiful pink stippled gingiva. Tooth #23 (mandibular left central incisor) has an 8 mm clinical attachment level (CAL) loss on the labial surface only, with visible root exposure but no tooth loss. Based on the 2017 AAP Classification, what is the most accurate diagnosis?

The generalized findings (BOP >85%, probing depths 2-3 mm with no CAL loss, pink gingiva, no bone loss, no tooth loss) are consistent with GENERALIZED GINGIVITIS. The isolated finding at tooth #23 (8 mm CAL on labial surface only, visible root exposure) is consistent with LOCALIZED GINGIVAL RECESSION — not periodontitis — especially when caused by a non-periodontic factor such as toothbrush abrasion, thin biotype, or labial tooth position. For a diagnosis of periodontitis, there must be interdental CAL at ≥2 non-adjacent teeth, OR buccal/lingual CAL ≥3 mm with pocketing >3 mm attributable to periodontitis (not another cause). In this case, the isolated labial recession at #23 without deep probing or bone loss does not meet periodontitis criteria. Correct diagnosis: Generalized plaque-induced gingivitis + localized gingival recession tooth #23 — most likely caused by mechanical (toothbrush) abrasion.