Abstract The aim of this study was to investigate the impact of smoking on gingival inflammation in a representative sample of 1,650 adults from Santiago (Chile), Porto Alegre (Brazil), and Tucumán (Argentina). A questionnaire was administered to participants to gather demographic and behavioral characteristics, including smoking habits. The participants were clinically examined to obtain gingival index (GI), gingival bleeding index (GBI), visible plaque index (VPI), and calculus presence values. Gingival inflammation was defined as a mean GI > 0.5. Heavy smokers presented significantly lower levels of gingival inflammation, as reflected by both GI and GBI, than both light and moderate smokers, despite their having increased amounts of plaque and calculus. Being 50 years old or older [odds ratio (OR), 1.93], a VPI ≥ 30% (OR, 28.1), and self-reported diabetes (OR, 2.79) were positively associated with detection of gingival inflammation. In conclusion, the occurrence of clinically detectable gingival inflammation was lower in heavy smokers than light and moderate smokers. Older age, diabetes, and visible plaque emerged as risk indicators of gingivitis. Plaque and gingival indices are significantly associated regardless of the smoking status.

ABSTRACT Objectives: The aim of this study is to investigate the prevalence and severity of gingival inflammation and associated risk indicators in South American adults. Material and Methods: Multi-stage samples totaling 1,650 adults from Porto Alegre (Brazil), Tucumán (Argentina), and Santiago (Chile) were assessed. The sampling procedure consisted of a 4-stage process. Examinations were performed in mobile dental units by calibrated examiners. A multivariable logistic regression model was utilized for associating variables as indicators of gingival inflammation (GI) (Gingival Index ≥0.5). Statistical significance was set at 0.05. Results: A total of 96.5% of the adults have GI. Regarding the severity of GI, 22.5% of participants examined have mild GI, 74.0% have moderate GI, and 3.6% have severe GI. The multivariate analyses identify the main risk indicators for GI as adults with higher mean of Calculus Index (OR=18.59); with a Visible Plaque Index ≥30% (OR=14.56); living in Santiago (OR=7.17); having ≤12 years of schooling (OR=2.18), and females (OR=1.93). Conclusions: This study shows a high prevalence and severity of gingival inflammation, being the first one performed in adult populations in three cities of South America.