Association of Interdental Cleaning and Untreated Root Caries in Adults in the United States of America

This study aimed to evaluate the association between interdental cleaning and untreated root caries amongst middle-aged and older adults in the US. Data were obtained from the National Health and Nutrition Examination Survey (NHANES) (2015–2016 and 2017–2018). Adults aged ≥40 years who underwent full mouth examination and root caries assessment were included. Participants were classified based on their interdental cleaning frequency as none, 1–3 d/wk, and 4–7 d/wk. Associations between interdental cleaning and untreated root caries were assessed using a weighted multivariable logistic regression model adjusted for sociodemographics, general behaviour, general health condition, oral conditions, oral health behavior, and dietary factors. Subgroup analyses stratified by age and sex were performed after adjusting for covariates in the logistic regression models. The prevalence of untreated root caries was 15.3% amongst 6217 participants. Interdental cleaning for 4–7 d/wk was a significant risk factor (odds ratio, 0.67; 95% confidence interval, 0.52–0.85). It was associated with a 40% reduction in the risk of untreated root caries in participants aged 40 to 64 years and a 37% reduction in women. Untreated root caries was also significantly associated with age, family income, smoking status, root restoration, number of teeth, untreated coronal caries, and recent dental visit. Interdental cleaning for 4–7 d/wk was associated with fewer untreated root caries amongst middle-aged adults and women in the US. The risk of root caries increases with age. Low family income was a risk indicator for root caries amongst middle-aged adults. Additionally, smoking, root restoration, number of teeth, untreated coronal caries, and recent dental visits were common risk factors for root caries in middle-aged and older people in the US.