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Maxillary morphology in obstructive sleep apnoea syndrome

Boon H. Seto, Helen Gotsopoulos, Milton R. Sims, Peter A. Cistulli
DOI: http://dx.doi.org/10.1093/ejo/23.6.703 703-714 First published online: 1 December 2001


The aim of this case‐control study was to test the hypothesis that maxillary morphology differs between obstructive sleep apnoea (OSA) patients and non‐snoring, non‐apnoeic subjects. Forty randomly selected patients [36 M, 4 F; mean age 49 ± 2 (SEM) years] with varying degrees of OSA (mean Apnoea/Hypopnoea Index 32 ± 4/hour) were compared with 21 non‐snoring, non‐apnoeic control subjects (18 M, 3 F; mean age 40 ± 2 years). An intra‐oral assessment of the occlusion was carried out, particularly for the presence or absence of posterior transverse discrepancies. Maxillary dental arch width was assessed by standardized lateral inter‐tooth measurements (inter‐canine, inter‐premolar, and inter‐molar) from dental models. Palatal height and maxillary depth were also measured. The maxillary dental arch was described by a 4th order polynomial equation. The ratios of maxillary to mandibular width (max/mand) and maxillary to facial width (max/facial) were determined from standardized postero‐anterior cephalometric radiographs in a subgroup of patients (n = 29) and all controls.

Twenty patients (50 per cent) had evidence of posterior transverse discrepancies compared with one control subject (5 per cent; P < 0.01). All patients had significantly reduced inter‐canine, inter‐premolar, and inter‐molar distances (P < 0.05). The maxillary depth was also shorter (P < 0.05), but palatal height was not different. The quadratic coefficient of the polynomial equation was greater in the patients than in the controls (P < 0.05), indicative of greater arch tapering. Patients had smaller maxillary to mandibular and maxillary to facial width ratios (P < 0.01). These results suggest that OSA patients have narrower, more tapered, and shorter maxillary arches than non‐snoring, non‐apnoeic controls. Further work is required to determine the relevance of these findings in the pathophysiology of OSA.