The control group received only conventional local anesthesia and psychological comfort measures. Preoperatively, medical staff communicated thoroughly with the child and guardian to explain the treatment process and precautions, alleviating anxiety. The child's oral and systemic health was assessed to determine treatment difficulty. During treatment, articaine (Septodont, France) were administered under strict aseptic techniques to minimize pain. Continuous psychological support was provided through gentle communication, encouraging gestures, and distraction techniques such as soothing music or storytelling to help the child relax and cooperate. Postoperatively, the child was observed for any adverse reactions before being discharged with their guardian.

The experimental group received nitrous oxide anesthesia using a professional dental nitrous oxide inhalation sedation system (Matrx, the United States). This system featured precise gas concentration adjustment, real-time patient vital sign monitoring, and a reliable alarm system to ensure accurate, safe, and stable nitrous oxide administration.

After the child was seated in the dental chair, an appropriately sized nasal mask was selected to ensure a secure fit without leakage. The child initially inhaled 100% oxygen for 3-5 minutes to adapt to the breathing pattern and eliminate nitrogen from the lungs. Nitrous oxide was then introduced at an initial concentration of 10%-15%, with adjustments made in increments of 5%-10% based on the child's anxiety level, treatment stimuli, and vital signs. Each adjustment was followed by 1-2 minutes of observation until the desired level of sedation was achieved.

The Modified Dental Anxiety Scale, zero is equivalent to no anxiety and 5 indicates the worst possible anxiety, participants achieved a response if they scored a performance status of 0 on a scale ranging from 0 (best outcome) to 5 (worst outcome)

The Frankl behavior rating scale was used to assess the children's behavior during treatment. This 4-point scale categorizes behavior , participants achieved a response if they scored a performance status of 1 on a scale ranging from 1 (best outcome) to 4 (worst outcome)

Children's Fear Survey Schedule-Dental Subscale, participants achieved a response if they scored a performance status of 1 on a scale ranging from 1 (best outcome) to 5 (worst outcome)

heart rate

blood pressure