Abstract: Objective: To determine the effectiveness and safety of three different sedation methods on patients with autism spectrum disorder during dental treatment. Methods: Ninety-one autistic children were selected and randomly divided into three groups, i.e. group M1 (n=29), group M2 (n=33), and group MD (n=29). They received intramuscular midazolam in 0.2 mg/kg, 0.24 mg/kg, and 0.2 mg/kg with intranasal dexmedetomidine in 2 μg/kg for sedation, respectively. Sedation effectiveness was analyzed by behavioral rating scales. Telephone following-ups were performed 24 hours after treatment to record the side effects and parents' satisfaction. Results: Children's vital signs were stable and no severe complications occurred. The degree of sedation in group MD was the deepest (group M1 vs. group MD, P<0.001; group M2 vs. group MD, P=0.004; group M1 vs. Group M2, P=0.047). The sedation depth had no relationship with age, sex, treatment program, or history. The sedation success rates in three groups were 31.0% (group M1), 42.4% (group M2), and 65.5% (group MD), with a significant difference among them. There was no significant difference in the treatment completion rates among three groups. The satisfaction rates of parents were 86.2%, 90.9%, and 86.2%, which were higher than the acceptance rates before treatment. Conclusion: Intramuscular midazolam with or without intranasal dexmedetomidine was an effective sedation method in dental treatment of pediatric patients with autism spectrum disorder. Combination of intramuscular midazolam and intranasal dexmedetomidine was associated with the best sedation effectiveness and the highest sedation success rate but longest onset time, when compared to other two groups of intramuscular midazolam.

Key words: autism spectrum disorder, midazolam, dexmedetomidine, sedation, pediatric dentistry