Effect of Nitrous Oxide–Oxygen Inhalation on Pain and Physiological Responses During Supragingival Ultrasonic Scaling: A Prospective Cohort Study

Background Nitrous oxide–oxygen (N 2 O–O 2 ) inhalation is widely utilized for anxiolysis in dentistry; however, its clinical efficacy and physiological impact during routine supragingival scaling remain insufficiently assessed. Methods This prospective observational cohort study enrolled 100 adult patients. Participants were allocated to either the N 2 O–O 2 sedation group ( n = 50) or a non‐sedated control group ( n = 50) based on treatment preference. Vital signs, including heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP), were monitored at baseline (T 0 ), intraoperatively (T 1 ), and postoperatively (T 2 ). Pain intensity was assessed immediately after supragingival ultrasonic scaling using a 0–10 Visual Analogue Scale. Results All 100 participants successfully completed the study. Intra‐group analysis revealed that the sedation group experienced a significant reduction in HR during scaling (T 1 ) compared to baseline (T 0 , p = 0.0004), whereas the control group remained physiologically stable with no significant HR fluctuations ( p > 0.05). SBP and DBP showed no significant intra‐group or inter‐group variations across all time points ( p > 0.05). Pain intensity was significantly lower in the sedation group compared with the control group ( p < 0.001). No adverse events were recorded. Conclusions N 2 O–O 2 inhalation sedation significantly attenuates procedural pain and stabilizes heart rate during supragingival ultrasonic scaling without compromising hemodynamic safety. These findings suggest N 2 O–O 2 sedation is a safe and feasible adjunct for routine periodontal prophylaxis.