Relationship Between Obstructive Sleep Apnea and Postoperative Pain After Endodontic Treatment: A Prospective Observational Clinical Study

Background: Sleep disorders and systemic inflammatory conditions influence pain perception. Obstructive Sleep Apnea (OSA), characterized by chronic intermittent hypoxemia, may affect postoperative pain response. This study aimed to evaluate postoperative pain following root canal treatment in patients with OSA accompanied by systemic comorbidities. Methods: This prospective observational study included 78 individuals (aged 28–63 years) divided into three groups based on polysomnography findings and medical histories: OSA with systemic comorbidities (Group 1, n = 24), systemic disease without OSA (Group 2, n = 24), and systemically healthy controls (Group 3, n = 30). All participants underwent standard single-visit root canal treatment. Postoperative pain was evaluated at 6 h, 24 h, and 7 days using a Visual Analog Scale (VAS). Results: No significant differences were observed in preoperative pain levels among the groups (p > 0.05). In the early postoperative period, Group 3 demonstrated higher pain scores than the other groups. At 6 h, pain levels in Group 3 were significantly higher than in Group 2 (p = 0.043), whereas at 24 h, Group 3 exhibited significantly higher pain scores than Group 1 (p = 0.002). By day 7, pain levels were similarly low across all groups. Conclusions: Lower early postoperative pain perception in patients with OSA and systemic comorbidities suggests that chronic inflammatory processes may modulate acute nociceptive responses. Therefore, low pain scores in this population should not be considered the sole indicator of clinical healing.