Measurement of Reduced Gingival Melanosis after Smoking Cessation: A Novel Analysis of Gingival Pigmentation Using Clinical Oral Photographs

Background: Due to moisture and the anatomical complexity of the oral mucosa, it is difficult to measure the extent of gingival melanosis in an optical manner. Therefore, we developed a new quantitative method using clinical oral photographs and compared the extent of gingival melanosis before and after smoking cessation. Methods: A new analysis method, which we named the gingival melanosis record (GMR), is a quantitative analysis method using clinical oral photographs. We obtained 659 clinical photographs from 263 patients from 16 general dental offices in Japan. Standardized measuring sites were automatically spotted on the screen, and the presence of gingival melanosis was determined at the measuring sites. We assessed the validity of the GMR with the previously reported Hedin’s classification using Spearman’s rank correlation and intraclass correlation coefficients. Results: The GMR showed a significant association with Hedin’s classification (p < 0.01, correlation coefficient = 0.94). The GMR also showed excellent reproducibility of the substantial repeated agreement intraclass correlation coefficients (ICC) (1,1) and ICC (2,1), p > 0.61). The longitudinal loss of gingival melanosis was confirmed by a change in the GMR among patients who successfully achieved smoking cessation for a mean of 4.5 years. Conclusion: The GMR is an effective method to assess gingival melanosis. The loss of gingival melanosis after smoking cessation can be objectively confirmed with the use of the GMR.