The aims of this study were to determine the differences in craniofacial morphology between children with obstructive sleep apnoea (OSA) and control subjects, and to investigate the effects of modified monobloc (MM) appliance treatment in OSA children. The treatment group consisted of 20 OSA Caucasian subjects (10 boys and 10 girls) with ages ranging from 4 to 8 years (mean 5.91 years). The control group comprised 20 healthy Caucasian subjects without OSA (10 boys and 10 girls) with ages ranging from 5 to 7 years (mean 6 years). Polysomnography was used to establish the diagnosis of OSA and to evaluate the effects of MM treatment in the test group. Cephalometric radiographs and study models were obtained for all subjects. A number of statistically significant differences were detected in craniofacial morphology between the treatment group and controls. The treatment group demonstrated a skeletal Class II pattern (P= 0.04), with a reduced mandibular length (P= 0.03) and a corresponding increase in overbite. The hyoid bone was located superiorly in the OSA group (P = 0.04). Analysis of the dental arches demonstrated a significantly smaller distance between the first and second inter-molar primary mandibular regions (P = 0.03 and P = 0.04, respectively) in OSA patients. Repeat polysomnography, with the MM in situ, after 6 months of wear, revealed a significant reduction in the apnoea-hypopnoea index in children with OSA (P= 0.0003). The MM was found to reduce daytime sleepiness and to subjectively improve assessed sleep quality. The patients and their parents reported good compliance with MM treatment.
Cephalometry Child