Association of melanin pigmentation in the gingiva of children with parents who smoke.

OBJECTIVE The association between gingival pigmentation and active smoking has been established. This investigation is the first to address the relationship between gingival pigmentation in children and passive smoking. METHODS A case-control study was performed involving 59 nonsmoking children who were selected from patient records of a dental clinic in a rural town in Japan. The number of subjects was based on a power calculation. Two calibrated examiners independently observed labial gingiva via oral photographs. RESULTS An interview determined that 61% of children had at least 1 smoking parent. Gingival pigmentation was observed in 71% to 78% of children. Interexaminer agreement was satisfactory (kappa = 0.73). Percentage of smoking parents was higher in children with gingival pigmentation (70-71%) than in those who lacked pigmentation (35%). Odds ratios of parental smoking adjusted by age and gender were 5.6 (95% confidence interval: 1.5-20.0) and 5.4 (1.4-21.2) for the 2 examiners. CONCLUSION These findings suggest that excessive pigmentation in the gingiva of children is associated with passive smoking. The visible pigmentation effect in gingiva of children could be useful in terms of parental education.