Inequality in dental flossing behavior among Korean adults based on household income levels.

Objectives: The aim of this study was to estimate the association between household income and dental flossing.

Methods: This cross-sectional study investigated the impact of household income on flossing among 9,391 adults aged 30+ with ≥20 natural teeth, utilizing data from the seventh Korea National Health and Nutrition Examination Survey (2016-2018). Outcome measures included flossing (yes/no), with income categorized into 4 levels: lowest, medium to low, medium to high, and highest. Logistic regression, adjusted for age, gender, brushing frequency, recent dental exams, periodontitis, smoking, and alcohol use, was employed to evaluate the influence of socioeconomic status on oral hygiene practices.

Results: In the highest income group, flossing was 62.6% more prevalent than in the lowest income group (adjusted odds ratio [aOR], 1.63; 95% CI, 1.27 to 2.08). The strongest association between income levels and flossing was observed in individuals aged ≥70 years (aOR, 3.64; 95% CI, 1.86 to 7.11), with a decreasing strength of association in the 60s (aOR, 1.72; 95% CI, 1.05 to 2.84) and 50s age groups (aOR, 1.69; 95% CI, 1.07 to 2.68). Higher-income women demonstrated a higher frequency of flossing than their lower-income counterparts (aOR, 1.67; 95% CI, 1.24 to 2.23). Higher-income individuals without periodontitis were more likely to floss (aOR, 1.64; 95% CI, 1.23 to 2.18), and among those with periodontitis, flossing was significantly associated only with the highest income category (aOR, 1.64; 95% CI, 1.10 to 2.44).

Conclusions: The findings of this study indicate a significant correlation between higher household income levels and an increased prevalence of flossing.