Relationships between smoking and melanin pigmentations in gingiva and lip

Objectives: The aims of present study were to examine relationships between smoking and melanin pigmentations in gingiva and lip. Materials and Methods: Standardized photos of buccal gingiva and lip were taken in 223 males. Melanin pigmentation of gingiva (MPG) and lip (MPL) were examined by the assessment of digital image on computer display in a standardized manner. Smoking status was asked by questionnaire. The examiner did not know smoking status of the subjects. Results: Among subjects, 52% were current smoker (CSM), 33 % were never smoker (NSM) and 25% were former smoker (FSM). MPG and MPL were found in 56% and 67% of subjects, respectively. Distributions of CSM, NSM and FSM were 75%, 11% and 14% for subjects with MPG and 22%, 60% and 18% for subjects without MPG. For subjects with MPL, the distributions were 63%, 23% and 14%, and 27%, 53% and 19% for subjects without MPL. MPG and MPL were significantly associated with current smoking (Reference=NSM, OR=17.8 and 5.6, 95% CI=8.5-37.5 and 2.9-11.0, respectively). The melanin index for MPG and number of sextant of MPL were significantly associated with daily consumption, duration of smoking and lifetime exposure (P<0.001-0.01). In the dose-response relationships, ED₅₀ was no more than 10 cigarettes, 10 years and 101 cigarette-years, respectively. The melanin index for MPG and sextant of MPL were significantly associated (P<0.001). Conclusion: These results indicate that melanocytes of gingiva and lip are very sensitive to active smoking, and suggest that the visible effects which appear in their body of current smokers could be realized and used for advice to quit smoking.