## 1 Introduction
Compared to traditional CT, CBCT has a shorter acquisition time and a more focused radiation beam with less scatter, resulting in lower radiation dosages and making it more appropriate for routine clinical use in a dental setting [28]. CBCT data can be used to assess skeletal craniofacial features and hard tissue structural abnormalities of the TMJ and can also provide a method of volumetric, cross-sectional area, and linear-dimensional airway analysis. Several 3D airway studies have shown smaller airway volumes and the most constricted cross-sectional area (MCCA) measurements in adults with OSA, as measured by CBCT, but less research has been conducted on pediatric populations [29; 30; 31; 32; 33]. Recently, a study was undertaken to compare the apnea hypopnea index (AHI) measured by polysomnography (PSG) to CBCT measures in pediatric OSA patients, and it was concluded that CBCT analysis may be a useful tool in the evaluation of the upper airway in pediatric OSA patients [34]. It was shown in both the nasopharynx and orophnx that airway volume as well as mean and minimal cross-sectional area were smaller in patients with moderate to severe OSA (AHI > 5) compared to primary snorers (AHI < 1) that were matched for age, gender, and obesity [34]. Another study relating AHI to CBCT airway data showed a statistically significant correlation between AHI and nasopharyngeal volume in children aged 7-11, as well as between AHI and the MCCA in the 12-17 age group [35]. Sleep-disordered breathing (SDB) and obstructive sleep apnea (OSA) may be among the functional impairments that JIA patients experience, which have been shown to be associated with pain, fatigue, and reduced health-related quality of life [36; 37; 38]. Daytime effects of OSA in children may include attention deficit, aggressive/impulsive behavior, hyperactivity, mood problems (including possibly depression/anxiety), poor school performance, headaches, fatigue, and excessive daytime sleepiness [39; 40]. Although OSA is not caused by anatomic factors alone, certain craniofacial characteristics have been shown to have significant associations with OSA/SDB [41]. A narrow or retrusive maxilla, retrongathic mandible, hyperdivergent mandibular plane angle, steep palatal plane angle, increased lower face height, decreased ratio of posterior to anterior face heights, anterior open bite, obtuse gonal angle, obtuse cranial base angle, and inferior position of the hyoid bone have been shown to be associated with pediatric OSA [41; 42; 43; 44; 45; 46; 47]. Arthritis involvement of the TMJ and the resulting retrognathia/micrognathia might be related to the increased OSA prevalence in JIA patients, as both are common in JIA, and both are risk factors for OSA [48; 49]. Attended PSG is one of the more predictable methods to diagnose OSA [39]. The prevalence of OSA determined by varying AHI thresholds in PSG in the general pediatric population is 1-4% [50]. Limited data exists to determine the prevalence of SDB/OSA problems in JIA patients, but it has been demonstrated that 40% of children with JIA had an AHI of greater than or equal to 1.5 events per hour, as measured by PSG [36; 51]. Pain, fatigue, and medication side effects are often attributed to causing sleep disturbances in JIA patients without screening for underlying OSA, and the average time from the diagnosis of JIA to the discovery of OSA (when present) by PSG is 2.5 years, which may be significant given the complications of OSA in overall health and disease management [49]. Most JIA patients with OSA are undiagnosed and untreated, which likely contributes to a poorer treatment response and worse patient-reported outcomes [36]. As the potential craniofacial morphology alterations associated with TMJ arthritis in JIA patients closely resemble those commonly associated with airway compromise in pediatric patients, it is of particular interest to investigate potential airway-related sequelae of JIA.