Abstract
BACKGROUND/PURPOSE: To investigate the associations between treated and untreated dental caries and periodontitis in young adults. MATERIALS AND METHODS: The study enrolled 1289 participants aged 18-45 years in Taiwan. Localized periodontitis was categorized into healthy and stage II/III (n = 936 and n = 353, respectively) based on the 2017 criteria of the World Workshop. Multivariable logistic regression analysis with adjustments for sex, age, tobacco smoking status, betel nut consumption status, metabolic syndrome, and total white blood cell count was used to determine the associations. RESULTS: Decayed tooth numbers were positively associated with localized stage II/III periodontitis [odds ratio (OR): 1.15 (95% confidence intervals (CI): 1.06-2.25)], while filled tooth numbers were inversely associated with localized stage II/III periodontitis in young adults [OR: 0.96 (95% CI: 0.92-0.99)]. CONCLUSION: Our study confirms the relationship between dental caries and periodontitis by direct evidence that the more decayed teeth there are, the higher the risk of periodontitis and by indirect evidence that the more treated decayed teeth there are, the lower the risk of periodontitis in young adults.