Prevalence and Risk Factors of Aphthous Ulcers Following Periodontal Surgery: A Cross-Sectional Analysis

<b>Background/Objectives:</b> This study aimed to determine the prevalence of aphthous ulcers following periodontal surgery and to identify demographic, behavioral, and clinical predictors of ulcer history before surgery and ulcer development after surgery. <b>Methods:</b> A cross-sectional study was conducted among 227 adult patients undergoing periodontal surgical procedures between November 2024 and May 2025. Demographic, medical, behavioral, and oral health data were collected. Postoperative follow-up at 1 and 2 weeks included a standardized clinical assessment of aphthous ulcers. Statistical analyses included descriptive statistics, chi-square tests, and Chi-squared Automatic Interaction Detection (CHAID) decision tree modeling. <b>Results:</b> Aphthous ulcers developed in 47 patients (20.7%), predominantly within the first postoperative week. CHAID analysis identified age, marital status, and smoking as predictors of preoperative ulcer history (classification accuracy: 73.6%), whereas age and family history predicted postoperative ulcer development (79.4%). Periodontal procedure type was significantly associated with postoperative medication prescription (χ² = 300.45, <i>p</i> < 0.001), suture selection (χ² = 69.19, <i>p</i> = 0.024), and ulcer number (χ² = 48.43, <i>p</i> = 0.031), but not ulcer size or anatomical location. Most ulcers were minor and primarily involved the buccal mucosa. <b>Conclusions:</b> Postoperative aphthous ulceration is a common complication of periodontal surgery, affecting approximately one-fifth of patients. Distinct risk profiles for pre- and post-surgical ulceration highlight the roles of patient-related susceptibility and surgical complexity. These findings support the use of structured risk stratification to guide preoperative counseling and targeted postoperative management.