A Cochrane review included 1 study with a total of 23 children. The study compared an oral appliance to no treatment, and assessed apnoea-hypopnoea, daytime symptoms (sleepiness, irritability, tiredness, school problems, morning headache, thirstiness in the morning, oral breathing and nasal stuffiness) and night-time symptoms (habitual snoring, restless sleep and nightmares measured by questionnaire). Statistically significant differences in the following results were found: reduction of the apnoea-hypopnoea index measured by polysomnography (RR 0.39, 95% CI 0.20 to 0.76); daytime symptoms measured by questionnaire: oral breathing (RR 0.16, 95% CI 0.04 to 0.59,) and nasal stuffiness (RR 0.18, 95% CI 0.05 to 0.69); and night-time symptoms measured by questionnaire: habitual snoring (RR 0.18, 95% CI 0.06 to 0.55), and restless sleep (RR 0.21, 95% CI 0.05 to 0.84).
Comment: The quality of evidence is downgraded by study limitations (lack of allocation concealment and blinding) and by imprecise results (few patients).