Association of 3D Mandibular Morphology, airway volume and OSA

Objectives: Various skeletal characteristics such as retrognathism of maxilla and mandible, Cl II skeletal pattern, and hyperdivergency contribute to reduced dimensions of upper airway and possibly increase the risk of obstruction during sleep. The objectives of the current study were to 1) Find possible correlations between mandibular skeletal features and upper airway volume, pediatric sleep questionnaire (PSQ), and Polysomnography (PSG) findings, 2) To evaluate differences in mandibular skeletal features in children with obstructive sleep apnea versus the control group.
Methods: De-identified pre-treatment Cone-beam Computed Tomography (CBCT) images, PSG findings, and PSQ results were collected retrospectively of 18 children (mean age 8.6 ± 1.97) from one pediatric dental practice. Scans were processed, digitized and segmented using Mimics v.20 software. Mandibular skeletal measurements: corpus length, ramus width, ramus height, gonial angle, mandibular transverse angle, transverse linear measurements at the levels of right and left mental foramens, lingulas, and gonions were recorded. Upper airway volume was segmented into right nasal cavity (RNC), left nasal cavity (LNC), nasopharynx (NP), oropharynx (OP) and hypopharynx (HP). Apnea Hypopnea Index (AHI), Respiratory Disturbance Index (RDI) from PSG studies and PSQ values were recorded and correlated with skeletal findings and airway volume using Pearson’s correlation. Student’s t-test was used to compare mandibular skeletal measurements in children with Obstructive Sleep Apnea and control group.
Results: There was no statistically significant difference in mandibular measurements of children with OSA versus the controls. HP volume was positively correlated with right and left corpus lengths (r= 0.858 and r=0.858, respectively). Mandibular transverse angle was negatively correlated to volume of HP (r=-0.552) and left and right corpus lengths (r=-0.588 and r=-0.698, respectively) and positively correlated to PSQ.
Conclusions: 1) Mandibular morphology is not correlated with sleep disordered breathing in young children.
2) Hypopharyngeal airway volume was the only segment of the airway that correlated with corpus lengths and mandibular transverse angle.