Maxillary transverse deficiencies (MTD) cause malocclusions. Rapid maxillary expansion treatment is commonly used treatment for correcting such deficiencies and has been found to be effective in improving respiration and sleep architecture in children with obstructive sleep apnoea (OSA). However, thus far, the effect of surgically assisted rapid maxillary expansion (SARME) treatment on sleep architecture and breathing of normal subjects has not been assessed. We hypothesised that sleep quality will improve after maxillary expansion treatment. The objective of this study is to access the effect of maxillary expansion treatment on sleep structure and respiratory functions in healthy young adults with severe MTD. This is a prospective and exploratory clinical study. Twenty-eight consecutive young adult patients (15 males and 13 females, mean age 20·6 ± 5·8 years) presenting with severe MTD at the orthodontic examination were recruited into the study. All the participants underwent a standardised SARME procedure (mean expansion 6·5 ± 1·8 and 8·2 ± 1·8 mm, intercanine and intermolar distance, respectively) to correct malocclusion caused by MTD. An overnight in-laboratory polysomnography, before and after the treatment, was performed. The mean follow-up time was 9 months. The main outcome parameters were the changes in sleep architecture, including sleep stages, arousals, slow-wave activity (SWA) and respiratory variables. Before surgery, young adult patients with MTD presented no evidence of sleep breathing problems. At baseline sleep recording, 7 of 28 (25%) had apnoea-hypopnoea index (AHI) ≥ 5 events per hour. No negative effect of the SARME was observed in questionnaires or sleep laboratory parameters. In the patients with a higher baseline AHI (AHI ≥ 5 h of sleep), we observed a reduction in AHI after surgical treatment (P = 0·028). SARME did not have a negative effect on any sleep or respiration parameters in healthy young individuals with MTD. It normalised the breathing index in the patients with a mild AHI index.

Scaphocephaly results from a premature fusion of the sagittal suture. Usually, cranial vault corrective surgery is performed during the first year of life. There is currently no scientific data regarding occlusion of scaphocephalic patients, or the potential effect of craniovault surgery on the occlusion. The aims were to describe occlusion in scaphocephalic patients and compare with a general pediatric population, and to compare the difference in occlusion of surgically versus unoperated treated scaphocephalic subgroup. A total of 91 scaphocephalic patients (71 boys aged between 2 and 11 y) seen at the Craniofacial Clinic of CHU Ste-Justine's formed the experimental group. All patients received an orthodontic assessment. Among them, 44 underwent craniovault surgery, whereas 47 remained unoperated. Thirty-eight (33 boys; 17 operated) had lateral cephalometric radiographies, some of them also had cephalometric growth follow-ups. Clinical values for dental classification and overjet indicate an increased prevalence of class II malocclusions in scaphocephalic patients. However, interestingly enough, cephalometric values indicative of skeletal class II malocclusions (ie, N-A perp HP, N-B perp HP, N-Pog perp HP, Wits, N-A-Pog) remained within normal limits. Some cephalometric values present statistically significant differences between operated and unoperated patients (ANS-PNS t2, P = 0.025; /1-FH t2, P = 0.028), but these are individual variations not related to scaphocephaly. Maxillary width of scaphocephalic children remains within normal limits. Scaphocephalic patients clinically presented more class II malocclusions compared with normal children. Radiographic values remain, however, within normal limits for both anteroposterior and transverse dimensions. Corrective craniovault surgery did not affect occlusion in these patients.