A randomized controlled trial is underway to evaluate whether a fixed nitrous oxide and oxygen mixture can reduce pain and anxiety during ultrasonic supragingival scaling.
The double-blind, placebo-controlled study will enroll 120 participants at a hospital dental clinic. Patients will be randomized in a 1:1 ratio to inhale either the fixed nitrous oxide/oxygen mixture or 100% oxygen. Gas delivery will begin 2 minutes before the procedure and continue throughout, administered via nasal mask with a non-return valve.
Eligible participants include adults with stage I to IV periodontitis and degree 2 or 3 dentin hypersensitivity. Participants must have a Visual Analogue Scale for Anxiety score greater than 5 and be classified as American Society of Anesthesiologists physical status I or II. Exclusion criteria include otitis media, sinusitis, upper respiratory infection, vitamin B12 deficiency, methylenetetrahydrofolate reductase deficiency, and sleep apnea.
Primary outcomes are pain and anxiety, measured using the Numeric Rating Scale and Visual Analogue Scale for Anxiety at four timepoints: before treatment (T0), 5 minutes into intervention (T1), 15 minutes into the procedure (T2), and 5 minutes post-procedure (T3). Both scales range from 0 to 10, with higher scores indicating greater severity.
Secondary outcomes include changes in heart rate, blood pressure, and oxygen saturation. These will be measured before, during, and after the procedure. Adverse effects such as nausea, vomiting, dizziness, or over-sedation will be recorded. Satisfaction from patients and providers will be assessed at the end of treatment.
Blinding will be maintained for patients, clinicians, and researchers. Identical gas cylinders will be labeled “A” or “B.” Unblinding will occur only in the event of medical emergencies.
Statistical analysis will follow the intention-to-treat principle using SPSS version 27. Continuous variables will be analyzed using Student t tests or Mann-Whitney U tests, depending on distribution. Repeated measures analysis of variance will be used for vital signs. A 2-sided P value of less than .05 will be considered statistically significant.
Sample size was calculated using GPower 3.1. A prior study indicated that 12 participants were sufficient to detect analgesic effects, but the sample size was increased to 120 based on regulatory guidance and to ensure safety assessment.
The authors reported no conflicts of interest.
Source: BMJ Open