A longitudinal study of dentofacial morphology in young children treated for the obstructive sleep apnoea syndrome

Abstract: The most common cause of OSAS in children is enlarged tonsils and/or adenoids. Consequently, the treatment for OSAS in children with enlarged tonsils and/or adenoids is adeno-/tonsillectomy. The prevalence of OSAS in children is 1-3%, with the peak incidence at the ages 2 to 6 years. There are few longitudinal studies presented in the literature on dentofacial morphology in children suffering from and treated for OSA. The aims of the present study were: to study the dentofacial morphology in children with OSAS and make comparisons with the morphology in children without obstructed airways; to evaluate prospectively the clinical manifestations, sleep recordings, and facial and dental development in children with OSAS before, and one and three years after adeno-/tonsillectomy; to longitudinally, during five years, evaluate the development of dentofacial morphology, soft tissue profile, and airway space after successful treatment of the OSA (adeno-/tonsillectomy), and to compare with the normal dentofacial development in non-obstructed children. The original sample comprised 20 consecutive prepubertal children, 8 girls and 12 boys, mean age of 6 years (age range 4 to 9 years), diagnosed as suffering from OSAS. All children were to be treated with tonsillectomy and/or adenoidectomy. Presurgically the OSAS children underwent clinical examination by an otolaryngologist, sleep registration with polysomnography (PSG), and orthodontic examination. Follow-up examinations and registrations were made 1, 3, and 5 years after surgical treatment. Results Before adeno-/tonsillectomy the most frequent observation during sleep was increased respiratory labour with increased use of accessory respiration muscles. In several children apnoeas/hypopnoeas >1/hour of sleep and low oxygen saturation in arterial blood (<89%) were observed. Compared to non-obstructed controls, the OSAS children exhibited a narrow upper dental arch, high frequency of lateral cross-bite, and reduced overbite. The patients also had a large lower anterior face height, a posteriorly inclined mandible and facial axis, and retroclined incisors. At the 1-year follow-up, none of the OSAS children exhibited clinical signs or symptoms of obstructive breathing. A catch-up in body weight was recorded. The width of the upper dental arch had increased significantly more (p<0.01) in the OSAS children than in the controls, and the lateral cross-bite had spontanously resolved in two patients. Furthermore, changes towards a more normal dentofacial development was seen in the patients. This beneficial trend could also be confirmed in the 3-year follow-up study. At the 5-year follow-up there was no significant difference between the OSAS children and the controls in the dimension of the nasopharyngeal airways. With the exception of the length of the anterior cranial base, which was still significantly smaller (p<0.01) in the OSAS children, than in the controls, there were no differences in dentofacial morphology between the groups. Conclusion Young OSAS children have a different dentofacial morphology compared with non-obstructed children. Treatment of OSA with adeno-/tonsillectomy was successful in the present patients, and the dentofacial development was normalised after surgery. It is important that OSA in young children is diagnosed early, and that the patients are evaluated both from a medical and dentofacial point of view.