Prevalence and Severity of Periodontitis in Patients with Ulcerative Colitis: A Case–Control Study

(1) Background: Current evidence suggests a possible association between ulcerative colitis (UC) and an increased risk of periodontitis. However, there is limited evidence regarding the severity of periodontitis in patients with UC. This study aimed to evaluate the prevalence and severity of periodontitis in patients with UC compared with healthy controls. (2) Methods: In this case-control study, 20 patients with UC and 40 age- and sex-matched controls from Ulaanbaatar Songdo Hospital underwent a full-mouth periodontal examination. Periodontitis was classified according to the 2017 classification system. Logistic regression was used to assess the relationship between UC and stage III/IV periodontitis. (3) Results: Patients with UC exhibited a significantly higher prevalence of periodontitis (95% vs. 72.5%) and stage III/IV periodontitis (55% vs. 20%, <i>p</i> = 0.011) than the controls. UC was associated with increased odds of stage III/IV periodontitis (OR = 4.0, 95% CI: 1.24-12.88, <i>p</i> = 0.02), and this association remained significant after adjusting for age and smoking status. However, after further adjustment for age and plaque levels, the association was attenuated and lost statistical significance. (4) Conclusions: Patients with UC demonstrated a higher prevalence and severity of periodontitis than healthy controls, including a significantly increased proportion of stage III/IV cases. These findings highlight the need for periodontal screening and oral hygiene education as part of the management of patients with UC in Mongolia.