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Objectives: The aim of this study was to evaluate the changes of upper airway ventilation function after molar distalization with aligners in adult patients by computational fluid dynamic simulation., Materials and Methods: A total of 15 subjects were included (3 males and 12 females, with an average age of 20.00 ± 0.50 years) who required en masse distal movement of the whole dentition using Invisalign aligners. The software Mimics 19.0 was used to reconstruct the upper airway based on their CBCT images and measure the minimum cross-sectional area and volume before and after treatment. Then the upper airway flow during inspirations was simulated and evaluated using Ansys software. At last, the morphologic and hydrodynamic parameters before and after treatment were compared using paired T-test., Results: For morphological evaluation, the volume changes of velopharynx, glossopharynx and hypopharynx volume revealed no statistically significance after treatment compared to the data before treatment, the minimum cross section of upper airway decreased significantly. For hydrodynamics parameters, the minimum pressure, maximum shear force, velopharynx and glossopharynx pressure drop increased 50.2 Pa, 0.66 Pa, 5.78 Pa and 5.32 Pa respectively. At last, the correlation analysis between CFD data and MCA is of no statistical significance., Conclusion: Non-extraction molar distalization using invisible aligners and mini-screws may lead to adverse changes in upper airway fluid dynamics, potentially increasing the risk of pharyngeal collapse., Clinical Relevance: The combination of invisible appliances with anchorage implants for the distalization of maxillary and/or mandibular teeth has emerged as a prevalent orthodontic technique. Clinicians should consider the potential impact on respiratory function when contemplating such treatment for patients with pre-existing respiratory conditions or those at a higher risk of ventilation issues., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Some orthodontic devices used in children share similar design principles to appliances used to treat obstructive sleep apnoea in adults. As well as treating malocclusion, orthodontic appliances used in children may therefore also have effects on the upper airway., Objective: A review of the literature to assess the effects of orthodontic treatment on the upper airway dimensions in children assessed on CBCT., Materials and Methods: Following registration of the protocol (PROSPERO CRD42023439056), a systematic electronic search of published studies was performed using several databases (PubMed; Scopus, Web of Science and Science Direct) in accordance with the PRISMA guidelines. Inclusion criteria were as follows: age under 18 years, orthodontic treatment with any appliance, a control group who received no treatment or a non-active alternative treatment and airway measurement using CBCT. RoB-2 and ROBINS-I tools were used to assess risk of bias and quality of the evidence., Results: In total, 341 studies were identified following the initial search. Title and abstract screening resulted in 45 studies for further full-text analysis. On completion of the screening process, a total of 23 studies met the inclusion criteria. Study interventions included functional appliances (10 studies), rapid maxillary expansion (RME) (9 studies), reverse-pull headgear (1 study) and 4 premolar dental extractions (3 studies). The included studies had moderate to high risk of bias, and the quality of evidence was low., Conclusion: The scientific evidence shows that functional appliances are associated with significant improvements in both upper airway volume and constriction when used in children however, the effects on the nasal cavity are limited. RME was associated with a significant increase in nasal cavity and nasopharyngeal dimensions, but not the upper pharyngeal airway. Neither reverse-pull headgear nor dental extractions were associated with any change in airway dimensions; however, the evidence is limited. Functional appliances may reduce the severity of obstructive sleep apnoea (OSA) in children., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

The aim of this study was to compare preoperative and postoperative linear, planar, and volumetric measurements in the pharyngeal airway in orthognathic surgery patients. Preoperative and postoperative cone beam computed tomography (CBCT) images of 60 patients, who underwent maxillary advancement with mandibular setback (Group I, n=25) and bimaxillary advancement (Group II, n=35), were compared. The airway was divided into 3 regions as nasopharynx, oropharynx, and hypopharynx. Linear and planar measurements were made on the reference sections of each region. The minimum axial airway area, the volume of 3 regions, and total airway volume were also measured. Regarding the linear, planar, and volumetric measurements, while there was a statistically significant increase in the measurements for all three regions in Group II, in Group I only the measurements in the nasopharyngeal region demonstrated a statistically significant increase postoperatively ( P <0.05). There was an increase in minimum axial airway areas in both groups; however, it was only statistically significant in Group II ( P <0.05). There was a statistically significant increase in total airway volumes in both groups ( P <0.05). A positive and good correlation was found between the percent increase in the minimum axial area and the percent increase in the total volume ( P <0.05). While bimaxillary advancement surgery results in a significant increase in the pharyngeal airway, mandibular setback with maxillary advancement caused an increase in the total airway. Changes that may occur in the airway should be considered while planning orthognathic surgery., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

Objective: This study aimed to explore the relationship between three-dimensional (3D) measurements of the hyoid bone (HB) and pharyngeal airway space (PAS) in relation to sagittal and vertical malocclusion., Methods: A total of 368 cone-beam computed tomography (CBCT) scans were classified into three skeletal groups (Class I, II, and III) and subdivided by vertical growth patterns (hypodivergent, normodivergent, and hyperdivergent). PAS dimensions, including nasopharyngeal, oropharyngeal, hypopharyngeal, and total airway spaces, were measured in surface area, volume, minimum constricted area (MCA), length, and width, HB position and dimension were analyzed in 3D using InVivo 6.0.3 and Dolphin 11.8 software. Data were analyzed using two-way ANOVA, and Bonferroni post-hoc tests, with P ≤ 0.05 considered significant., Results: The study found that patients with skeletal Class III and hypodivergent growth pattern had the highest sagittal position of the hyoid bone, while those with skeletal Class II and hyperdivergent pattern had the lowest hyoid length. Nasopharyngeal airway space width was significantly lower in skeletal Class III patients, while volume and area were lower in hyperdivergent patients. Oropharyngeal and hypopharyngeal dimensions were also affected by skeletal class and growth pattern, with hyperdivergent patients having the lowest values. Total pharyngeal volume, area, and minimum constricted area were also affected, with hyperdivergent patients having the lowest values and skeletal Class II patients having the lowest minimum constricted area., Conclusion: Pharyngeal airway dimensions and hyoid bone parameters vary with malocclusions. The hyoid bone's position influences the airway, identifying patients at risk for airway obstruction and sleep-disordered breathing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Objective: This study aimed to investigate the normal volumetric space and variations in the measurements of different landmarks in adults with different skeletal relations of the maxilla and the mandible based on CBCT data. The study also analyses these landmarks to locate any correlations., Background: Numerous studies in orthodontics have found a relationship between orthodontic treatment and changes in the anatomy and function of the airway. Severe changes in airway morphology can cause breathing difficulties, lower quality of life, and even result in life-threatening conditions such as obstructive sleep apnoea. Consequently, orthodontic diagnosis and treatment planning require a thorough understanding of the airway space and its function., Methods: The present retrospective study was conducted using CBCT records of 120 adult patients, containing 40 samples of each skeletal class (20 males and 20 females). The boundaries were defined for the 3 major regions: the nasopharynx, the oropharynx, and the hypopharynx. Various measurements were recorded across these regions, as well as selective cephalometric landmarks. The obtained data was used to calculate average and standard deviation, while regression analysis was used to evaluate correlations and t-test was used to test statistical significance of gender differences., Results: The results demonstrate that skeletal Class III individuals exhibit a reduced airway volume in the nasopharynx compared to other groups, whereas skeletal Class II individuals displayed a diminished airway volume in the hypopharynx. A strong correlation was observed for Sella turcica parameters. There were no significant differences in skeletal parameters across genders. Nasopharynx cavity volume demonstrated significant differences between skeletal Class I-Class III as well as between skeletal Class II-Class III. Hypopharynx cavity volume also demonstrated significant differences between skeletal Class I-Class II and between skeletal Class II-Class III., Conclusion: The major findings are the presence of a reduced nasopharyngeal volume in skeletal Class III malocclusions while skeletal Class II individuals displayed a diminished hypopharyngeal volume, making these critical areas to consider during the diagnostic and orthodontic treatment planning stages. This study also revealed a consistent correlation between Sella turcica parameters across various facial skeletal profiles, with skeletal Class II patients exhibiting a distinct pattern and skeletal Class I and Class III demonstrating an average relationship., (© 2024. The Author(s).)

Objective: To explore the accuracy of a multi-task model based on vision Transformer for analyzing the three-dimensional (3D) upper airway and its subregions, and to evaluate its clinical applicability. Methods: According to the inclusion and exclusion criteria, cone-beam CT (CBCT) data of 10 patients [4 males and 6 females, (20.8±2.7) years] who had their first visit to the Department of Orthodontics in the Hospital of Stomatology, Wuhan University from January 2012 to January 2020 were retrospectively selected. The 3D slicer software was used to segment the upper airway and pharyngeal airway and measure their volumes as the gold standard. The Dolphin 3D software was used to segment the pharyngeal airway and its subregions and measure their volumes as the gold standard. A multi-task model based on vision Transformer developed by the research team for automatic segmentation and volume measurement of the upper airway and its subregions. All the measurements were conducted by the same attending physician. The Bland-Altman analysis and intraclass correlation coefficient ( ICC ) were used to evaluate the consistency between the multi-task network and the gold standard in the upper airway segmentation and volume measurements, and the paired t test was used to compare the differences between the multi-tasking model and the gold standard. Results: The mean volume deviation of the upper airway segmented by multi-task model and 3D Slicer was -979.6 mm 3 , and the ICC was 0.97. The mean volume deviation of the pharyngeal airway, nasopharynx, velopharynx, glossopharynx and hypopharynx segmented by multi-task network and Dolphin 3D were 2 069.5, -950.1, -823.6, -813.9 and 4 003.4 mm 3 , respectively. In addition, ICC in pharyngeal airway, nasopharynx, velopharynx, glossopharynx and hypopharynx were 0.97, 0.94, 0.96, 0.96 and 0.69, respectively. Conclusions: The multi-task model based on vision Transformer produced different errors in the segmentation of 3D upper airway and its subregions. The segmentation of the nasopharynx, velopharynx and glossopharynx was in good agreement with the gold standard, while the segmentation of hypopharynx was poor, suggesting that the robustness and generalization of this model should be further enhanced.

Background: Natural head position (NHP), pharyngeal airway and maxillofacial growth pattern are correlated. The author's previous studies proved that following surgical correction of Skeletal Class II malocclusion, the over-extended NHP returned upright, and the pharyngeal airway space (PAS) dimension expanded., Objective: The present study compares the post-operative change in NHP and PAS after orthognathic surgery in Skeletal Class II and III malocclusion patients., Methods: Patients receiving orthognathic procedures to correct Skeletal Class II or III malocclusions were reviewed in this retrospective study. Pre-operative and 6-week post-operative cone-beam computed tomography datasets were collected. Variables representing the craniofacial pattern, the NHP and the PAS were measured three-dimensionally. Post-operative variables were compared with their pre-operative counterparts using either repeat-measure 2-way analysis of variance or Wilcoxon matched-pairs signed rank test., Results: Thirty cases of Skeletal Class II malocclusion and 13 cases of Skeletal Class III malocclusion were collected. Preoperatively, the inter-group differences were significant in craniofacial pattern (68.14 ± 3.552 degree vs. 79.63 ± 2.497 degree, p < .0001) and the NHP (68.77 ± 11.02 degree vs. 82.83 ± 7.738 degree, p = .0002) while not significant in PAS; after surgery, the intergroup differences in craniofacial pattern and the NHP between groups decreased, and the PAS increased in both groups., Conclusion: Orthognathic surgery may improve compromised NHP and increase PAS in Skeletal Class II and III malocclusion patients., (© 2024 The Author(s). Journal of Oral Rehabilitation published by John Wiley & Sons Ltd.)

Purpose: This study aimed to compare the effects of two different mandibular advancement devices on the upper airway volume, polysomnographic parameters, and sleepiness scale scores in patients with obstructive sleep apnea and Temporomandibular disorders (TMD)., Materials and Methods: Monoblock and twinblock mandibular advancement devices were applied to patients with obstructive sleep apnea syndrome for 3 months separated by a wash-out period of 2 weeks. Research Diagnostic Criteria for TMD (RDC/TMD), Polysomnographic parameters and cone-beam computed tomography findings were recorded before and after the use of the mandibular advancement devices. A three-dimensional analysis of the airway was then performed., Results: The use of the monoblock device significantly increased the upper airway volume compared with the use of the twinblock device (p = 0.032). The polysomnographic parameters similarly improved with the use of the twin-block and monoblock devices. The significant reduction in TMD symptoms was observed., Conclusion: The use of the monoblock device increased the retropalatal airway volume. This volume increase may be attributed to the fact that the design of the monoblock device allows less mandibular movement than does that of the twinblock device. Indicates the potential benefits of MAD S treatment in alleviating TMD-related issues., Clinical Significance: Monoblock MADs have improved effects on respiratory parameters and upper airway dimensions in patients with OSA and mild to moderate TMD., (© 2024. The Author(s).)

Background: Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder characterized by repetitive collapse of the upper airway during sleep. However, little evidence is available on the differences between the sub-regions of the upper airway morphology and OSA severity. Since orthodontists frequently perform cone beam computed tomography (CBCT) in the neck area, we aimed to investigate the relationship and the differences between upper airway morphology and OSA severity using CBCT., Materials and Methods: The medical records, CBCT imaging of 21 OSA patients diagnosed by polysomnography, and the apnea-hypopnea index (AHI) results were included to classify OSA severity as mild, moderate, or severe. The minimum cross-sectional areas (MCA) and volumes of the upper pharyngeal airway boundaries in four sub-regions: nasopharynx, retropalatal, retroglossal, and hypopharynx were measured. Dolphin Imaging software was used for upper airway segmentation. The correlation coefficient (r), one-way ANOVA, and the least significant difference post hoc multiple comparison test were applied to fulfill the objectives., Results: A statistically significant relationship was found between the MCA of the nasopharynx and the AHI (r = -0.473, P < 0.05). Furthermore, a difference was found between mild and moderate and moderate and severe OSA severity in the MCA results of the retroglossal region (P < 0.05). However, no relationship was found between the upper airway volume and OSA severity., Conclusions: MCA was moderately negatively correlated to AHI only in the nasopharynx subregion. Moderate OSA presented significantly less MCA than mild and severe OSA only in the oropharynx and retroglossal subregions., (Copyright © 2024 World Federation of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: To evaluate changes of the upper airway and oral cavity volumes in patients with skeletal Class III malocclusion undergoing bimaxillary orthognathic surgery, and to analyze the correlation between postoperative upper airway decrease and the amount of jaw movement and oral cavity volume reduction., Materials and Methods: Thirty patients (16 males and 14 females) undergoing bimaxillary surgery were included. Three-dimensional reconstruction of the upper airway and oral cavity were performed using preoperative (T0) and postoperative (T1) (6 months) cone-beam computed tomography scans., Results: The volume, sagittal area and minimum cross-sectional area of the upper airway were diminished (P < .001). The decrease in volume and minimum cross-sectional area in the oropharyngeal region of the upper airway were weakly correlated with B-point posterior movement (P < .05). Total oral cavity volume was decreased, with maxillary oral volume increasing and mandibular oral volume decreasing (P < .001). Upper airway decrease was highly correlated with total oral volume reduction and mandibular oral volume reduction, with the most significant correlation being with total oral volume reduction (P < .001)., Conclusions: Class III bimaxillary surgery reduced the volume, sagittal area, and minimum cross-sectional area of the upper airway as well as oral cavity volume. Upper airway changes were weakly correlated with anterior-posterior mandibular movement but significantly correlated with oral cavity volume changes. Thus, oral cavity volume reduction is a crucial factor of upper airway decrease in patients with skeletal Class III malocclusion undergoing bimaxillary orthognathic surgery., (© 2024 by The EH Angle Education and Research Foundation, Inc.)

Objective: This study aimed to evaluate the effects of nasal septum deviation on the pharyngeal airway and craniocervical posture measurements using cone beam computed tomography (CBCT)., Methods: This retrospective study analyzed the CBCTs of 25 patients with and without nasal septum deviation. Various parameters defining the pharyngeal airway and craniocervical and facial skeletal morphology were measured and compared between the groups after confirming intra-examiner reliability., Results: Compared to the control group, the group with nasal septum deviation had a statistically significantly shorter nasopharyngeal length ( p < 0.001), longer vertical airway length ( p < 0.002), and larger cervical column curvature angle ( p < 0.006)., Conclusion: Children with a nasal septum deviation of 4 mm or more on their CBCT scan are susceptible to unfavorable pharyngeal airway and craniocervical postural changes.

Introduction: The objective of this study was to investigate the 2-year postoperative change and influencing factors of the upper airway after mandibular advancement with maxillary setback surgery for patients with a skeletal Class II relationship., Methods: Fifty-seven participants who underwent mandibular advancement with maxillary setback surgery were enrolled consecutively. Cone-beam computed tomography was performed preoperatively, 3 months postoperatively (T1), and 2 years (T2) postoperatively. All parameters were measured using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif)., Results: The total volume (V), minimum cross-sectional area (CSA min ), and glossopharynx increased significantly in both the short-term (V, 13.33%; CSA min , 33.03%; glossopharynx, 26.73%) and long-term (V, 10.19%; CSA min , 23.18%; glossopharynx, 18.27%) after the surgery. Mandibular advancement, mandibular width increase, preoperative CSA min , and body mass index (BMI) significantly affected 2-year postoperative V increases. Mandibular advancement and BMI significantly affected 2-year postoperative glossopharynx increases. Backward movement of point PNS may lead to a reduction of the nasopharynx; however, downward movement of point PNS, upward movement of point A, and increased maxillary width may compensate for this effect by increasing the likelihood of the nasopharynx opening. Furthermore, mandibular body length at T1 is positively associated with relapse rate ([T2 - T1] / T1) of V and CSA min ., Conclusions: Mandibular advancement amount, mandibular width increase, preoperative CSA min , and BMI are the 4 factors for long-term V changes. Patients with a longer mandibular body length might have a lower relapse rate., (Copyright © 2023 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Background: The present study evaluated the three-dimensional changes of the pharyngeal airway after orthognathic surgery (OGS) in patients with unilateral and bilateral clefts, and in unilateral cleft patients with and without pharyngeal flap (PF)., Methods: Forty-five patients with unilateral or bilateral clefts undergoing OGS were enrolled. Cone-beam computed tomographic images were obtained before and after OGS. We measured the pharyngeal airway volumes, minimal cross-sectional area, and the horizontal displacement of facial landmarks., Results: The patients with bilateral cleft exhibited smaller initial velopharyngeal volume (unilateral, 8623 mm 3 ; bilateral, 7781 mm 3 ; P = 0.211), whereas the velopharyngeal volume increased significantly with a median of 744 mm 3 after OGS ( P = 0.031). The median horizontal displacement of A point was 2.9 and 2.6 mm among the patients with unilateral and bilateral clefts, respectively ( P = 0.276), and the median horizontal displacement of B point was -2.9 and -3.3 mm among patients with unilateral and bilateral clefts, respectively ( P = 0.618). The unilateral cleft patients with PF exhibited lower initial velopharyngeal volume (patients with a history of PF surgery, 7582 mm 3 ; patients without a history of PF surgery, 8756 mm 3 ; P = 0.129) and a lower increase in velopharyngeal volume (patients with a history of PF surgery, 437 mm 3 ; patients without a history of PF surgery, 627 mm 3 ; P = 0.739) after OGS., Conclusions: Midface hypoplasia and the decrease in the velopharyngeal volume were more prominent among the bilateral cleft patients and the unilateral cleft patients with PF. After OGS, the velopharyngeal volume increased considerably among the bilateral cleft patients, but no considerable differences were noted among the unilateral cleft patients with PF., Clinical Question/level of Evidence: Risk, II., (Copyright © 2023 by the American Society of Plastic Surgeons.)

Objectives: The medium-term effects of rapid maxillary expansion (RME) on nasal cavity (NC) and upper airway (UA) dimensions based on chronological age are still unclear. This retrospective study evaluated the medium-term changes occurring in the NC and pharyngeal airways (PA) after RME in two distinct age-based cohorts of patients., Methods: This retrospective study included 48 subjects who underwent RME grouped in two cohorts: a 6-9-year-old group (EEG group: early expansion group - 25 subjects) and an 11-14-year-old group (LEG group: late expansion group - 23 subjects). NC and PA volumes were analyzed from CBCT imaging segmentation before RME (T0) and twelve months after RME (T1). The amount of maxillary expansion (PW) and minimal cross-sectional area (CSmin) were also considered., Results: All PAs' volumetric sub-regions, CSmin and PW showed a significant volumetric increment (p < 0.05). Inter-group comparisons showed significant differences (p < 0.05) for nasopharynx and CSmin parameters (p < 0.05), while no significant changes were recorded for the other UA's sub-regions and PW (p > 0.05). According to a deviation analysis, part of the UA increase (more marked for the nasopharynx area) may have occurred due to reduced adenotonsillar tissues, which were larger in the EEG group., Conclusions: Twelve months after treatment, clinicians should not expect changes in the UAs dimensions to be solely related to treatment effects of RME; instead, normal craniofacial growth changes and spontaneous regression of the adenotonsillar tissue could represent the most significant factors influencing UAs changes., Clinical Significance: From the clinical perspective, the results of the present study encourage caution when considering the therapeutic effects of RME on airways dimensions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: This study aimed to determine the three-dimensional (3D) correlation between maxillomandibular complex parameters and pharyngeal airway dimensions in different sagittal and vertical malocclusions., Methods: This retrospective cross-sectional study included the CBCT scans of 368 patients with a mean age of 23.81 ± 3.01 years. The patients were classified into three groups (skeletal Class I, II, and III). Each class group was divided into three subgroups based on vertical growth patterns (hypo-, normo-, and hyperdivergent). The maxillomandibular complex was evaluated in the three planes using 16 skeletal measurements. Naso-, oro-, hypo-, and total pharyngeal airway spaces were assessed in terms of width, volume, surface area, and minimum constricted area (MCA). Two-way ANOVA followed by the Bonferroni post-hoc test were used., Results: The nasopharyngeal airway space was significantly lowest regarding sagittal and lateral widths in the skeletal Class III patients, the lowest volume and surface area were in hyperdivergent patients, and MCA was the highest in Class II and hypodivergent patients. The oro- and hypopharyngeal sagittal width, volume, surface area, and MCA were the lowest in the hyperdivergent patients, and oropharyngeal lateral width and hypopharyngeal sagittal width were the highest in skeletal Class III. The total pharyngeal volume, surface area, and MCA were the lowest in the hyperdivergent patients, and skeletal Class II patients had the lowest MCA., Conclusions: The pharyngeal airway dimensions differ with various sagittal and vertical malocclusions. These differences could apply to diagnosis, treatment planning, and possible changes following orthodontic/orthopedic or surgical treatment.

This study aims to generate and also validate an automatic detection algorithm for pharyngeal airway on CBCT data using an AI software (Diagnocat) which will procure a measurement method. The second aim is to validate the newly developed artificial intelligence system in comparison to commercially available software for 3D CBCT evaluation. A Convolutional Neural Network-based machine learning algorithm was used for the segmentation of the pharyngeal airways in OSA and non-OSA patients. Radiologists used semi-automatic software to manually determine the airway and their measurements were compared with the AI. OSA patients were classified as minimal, mild, moderate, and severe groups, and the mean airway volumes of the groups were compared. The narrowest points of the airway (mm), the field of the airway (mm 2 ), and volume of the airway (cc) of both OSA and non-OSA patients were also compared. There was no statistically significant difference between the manual technique and Diagnocat measurements in all groups (p > 0.05). Inter-class correlation coefficients were 0.954 for manual and automatic segmentation, 0.956 for Diagnocat and automatic segmentation, 0.972 for Diagnocat and manual segmentation. Although there was no statistically significant difference in total airway volume measurements between the manual measurements, automatic measurements, and DC measurements in non-OSA and OSA patients, we evaluated the output images to understand why the mean value for the total airway was higher in DC measurement. It was seen that the DC algorithm also measures the epiglottis volume and the posterior nasal aperture volume due to the low soft-tissue contrast in CBCT images and that leads to higher values in airway volume measurement., (© 2022. The Author(s).)

Introduction: Studies on the pharyngeal airway space (PAS) changes using three-dimensional computed tomography (CT) have shed more light on patients with Class III than Class II malocclusion. This paper focuses on analyzing the long-term changes in the PAS and evaluating the postoperative association between these PAS and skeletal changes in patients with skeletal Class II malocclusion who have undergone orthognathic surgery., Methods: The records of 21 patients with skeletal Class II malocclusion who had undergone orthognathic surgery were included. The anatomical modifications in both jaws, changes in volume, sectional area (SA), minimum sectional area (MSA), and anterior-posterior (AP) and transverse (TV) width in the airway at one month before surgery ( T 0), and one month ( T 1) and one year ( T 2) after surgery were analyzed using CT images. The association between the skeletal and airway changes was evaluated between T 0, T 1, and T 2., Results: After surgery, the ANS, A point, and PNS demonstrated significant posterior and superior movement. The B point and the pogonion exhibited substantial anterior and superior movement. The total and inferior oropharyngeal volumes (vol 3, vol 4) notably increased, while the nasopharyngeal volume (vol 1) decreased. The anterior-posterior movement at the ANS and PNS after surgery was significantly associated with the total volume, vol 2, vol 3, SA 1, MSA, and TV width 1, while substantial association with the total volume was found at the pogonion., Conclusion: Thus, an ideal treatment plan can be formulated for patients with skeletal Class II malocclusion by considering the postoperative PAS changes., Competing Interests: The authors have no conflict of interest to declare that is relevant to this review paper., (Copyright © 2022 Moonhwan Kim et al.)

The objectives of the present study were to compare measurements of pharyngeal airway subregions on lateral cephalometric (LC) and cone beam computed tomographic (CBCT) images in relation to skeletal classes and discuss the advantages and disadvantages of these imaging formats for this type of assessment. The CBCT images were assessed via both multiplanar reconstruction (MPR) and 3-dimensional (3D) reconstruction. The LC and CBCT images from 107 patients were classified according to skeletal class: I, n = 35; II, n = 35; and III, n = 37. Linear measurements of the subdivisions of the upper airway were performed on the LC, MPR, and 3D images. In addition, area and volumetric measurements were performed on the MPR images. The relationships among imaging methods, skeletal class, and pharyngeal thirds were assessed by means of a 1-way analysis of variance (α = 0.05). No statistically significant differences in the linear, area, or volumetric measurements of the upper airway subregions were found among the skeletal classes (P > 0.05). For the linear measurements in the oropharynx and hypopharynx, greater values were observed for the LC images than for the MPR and 3D images (P ≤ 0.05). Based on the study findings, MPR images should be preferred for visualization of the pharyngeal airway subregions. However, LC imaging is preferable to 3D reconstruction., Competing Interests: The authors report no conflict of interest pertaining to any of the products or companies discussed in this article.

Introduction: After a century of controversies, we are still not certain on the relationship between airway volume and facial morphology., Objective: To measure nasopharyngeal airway volume and compare it among different skeletal patterns., Materials and Methods: Forty five CBCT scans of patients between sixteen to twenty five years were used in the study. The nasopharyngeal airway was divided into upper, middle and lower segments. CBCT images were grouped into skeletal class I, class II and class III., Results: There was highly significant difference in upper (p=0.001) and middle pharyngeal airway volume (p<0.001) among 3 skeletal groups. Lower pharyngeal airway volume was also statistically significant (p=0.051) among 3 groups. Total pharyngeal airway volume did not show any significant correlation., Conclusion: Nasopharyngeal airway volume seems to play a role in different skeletal patterns., (This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Purpose: Ectodermal dysplasias (EDs) are a diverse set of hereditary conditions in which 2 or more ectodermal structures develop abnormally. The purpose of this study was to use cone-beam computed tomography (CBCT) scans to measure the pharyngeal airway volume and minimum cross-sectional area (MC) among patients with ED and compare them with healthy controls., Patients and Methods: The pretreatment CBCT scans of 9 individuals with ED and 61 controls were analyzed. Lateral cephalograms were created from the CBCT volumes and then traced and compared between the 2 groups. Airway volumes were evaluated by Dolphin 3D software (Dolphin Imaging, Chatsworth, CA) to compare the total pharyngeal volume, nasopharyngeal volume, oropharyngeal volume, hypopharyngeal volume, and MC. The mean airway volumes of the 2 groups were compared, and the odds ratio and relative risk of having an MC of less than 100 mm 2 in the ED group were calculated., Results: Intraclass correlation analysis showed excellent inter-rater reliability. All cephalometric features of controls were within the norms of patients with ideal skeletal-dental relationships. Patients with ED displayed significantly lower values for SNA (angle between sella-nasion and nasion-A point) (P = .018), ANB (angle between nasion-A point and nasion-B point) (P = .002), L1-MP (angle between long axis of mandibular incisor and gonion-menton plane) (P = .013), and L1-NB (distance between mandibular incisor and perpendicular line between nasion and B point) (P < .001). Although the ED group exhibited slightly smaller airway volumes for all subregions, the differences were not statistically significant for total pharyngeal volume, nasopharyngeal volume, oropharyngeal volume, hypopharyngeal volume, or MC (P > .05). The odds of having an MC of less than 100 mm 2 were almost 3 times greater among ED patients, and the relative risk of an MC of less than 100 mm 2 among ED patients was double that of controls., Conclusions: Although the craniofacial structures of individuals with ED are characterized by maxillary and midface deficiency, the airway volumes among affected individuals may not be significantly different from those of unaffected controls. However, patients with ED displayed a higher risk of having an MC of less than 100 mm 2 , which may be of clinical significance and warrants further investigations with larger samples., (Copyright © 2020 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives/hypothesis: Individuals with orofacial clefts often experience respiratory problems because of nasopharyngeal abnormalities. Pharyngeal airway morphology is thought to differ among the various cleft types. We measured three-dimensional (3D) airway volume using cone-beam computed tomography (CBCT) analysis to evaluate and compare pharyngeal airways in Japanese preschoolers with and without orofacial clefts., Study Design: Retrospective case-control study., Methods: We enrolled 83 subjects (37 boys, 46 girls; mean age = 4.66 ± 0.56 years) with nonsyndromic orofacial clefts and 16 noncleft healthy subjects (seven boys, nine girls; mean age = 5.30 ± 0.52 years) as controls. The subjects were divided into five groups. Four groups were based on the cleft type: isolated cleft palate, unilateral cleft lip and alveolus), unilateral cleft lip and palate, and bilateral cleft lip and palate. The fifth group included the noncleft controls. All subjects were examined with CBCT, and the 3D airway volume was measured. We analyzed group differences statistically using analysis of covariance with the Bonferroni post hoc pairwise comparison tests for the corrected means., Results: Compared with the noncleft group, each cleft group exhibited significantly decreased total and nasal airway volumes and increased superior and inferior pharyngeal airway volumes. The differences were all statistically significant., Conclusions: Our findings suggest that anatomical differences exist in pharyngeal airway volumes among various cleft groups and in those without a cleft., Level of Evidence: 3b Laryngoscope, 130:533-540, 2020., (© 2019 The American Laryngological, Rhinological and Otological Society, Inc.)

Introduction: Pharyngeal airway space (PAS) assessment has been used in the past for a better understanding of orthodontic and surgical outcomes; however, this analysis could be unreliable. Our objective was to evaluate possible changes in the PAS reading in the same patient from their consecutive cone-beam computed tomography (CBCT) scans., Methods: We evaluated a total of 27 patients' CBCT scans obtained at 2 time points with the use of a standardized acquisition protocol. The mean age at T0 was 31 years (range 17-62 years) and the follow-up records (T1) were taken after 4-6 months. Dolphin Imaging software was used to measure the volumes of the nasopharynx, oropharynx, and hypopharynx. We also evaluated the craniocervical position with the use of a lateral cephalogram., Results: The variables exhibited high intraclass correlation coefficients (ICCs) when measuring the same CBCT scan twice (T0 and T0). However, The ICC between the measurements performed on the first and second CBCT scans (T0 and T1) showed that the only variable with high reproducibility between the 2 scans was cranial base, with an ICC >0.97. Average differences of 682.1 mm 3 , 2255.3 mm 3 , and 517.4 mm 3 were found for the nasopharynx, oropharynx, and hypopharynx, respectively. Regarding the cephalometric angles, average differences between T0 and T1 scans were 0.6°, 2.7°, and 0.4° for OPT.CVT, OPT.SN, and cranial base, respectively., Conclusions: Different CBCT exams with equal scanning and patient positioning protocols can result in different 3D PAS readings. A more careful interpretation of CBCT volumetric data to achieve adequate conclusions of the clinical outcomes is necessary., (Copyright © 2019 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: To test the null hypothesis that there is no significant difference in pharyngeal airway space among adult skeletal Class II patients with different condylar positions using cone-beam computed tomography (CBCT)., Materials and Methods: The CBCT records of 60 patients with skeletal Class II malocclusion (ANB angle ≥ 4°, Wits ≥ 0) were selected from the CBCT database. According to the condyle position, the patients were divided in three groups: anterior group (CD ≤ -12%), centric group (-12% ≤ CD ≤ +12%), and posterior group (CD ≥ +12%). Three-dimensional (3D) pharyngeal airway models were reconstructed using InvivoDental software 5.1.3. The volume and area of the pharyngeal airway space were measured in the 3D airway model., Results: The volume and area of the pharyngeal airway space in the centric group were significantly smaller than those in the posterior group ( P < .01). The volume and area of the pharyngeal airway space were smallest in the anterior group and significantly increased in the centric and posterior groups ( P < .001)., Conclusions: The null hypothesis was rejected. Significant differences were noted in pharyngeal airway space among adult skeletal Class II patients with different condylar positions.

Objectives: Obstructive sleep apnea syndrome (OSAS) becomes increasingly important. For diagnosis and surgery, computed tomography (CT), and cone beam computed tomography (CB-CT) are used equally, although in most of cases, patient positioning differs between supine positioning (CT) and upright seating positioning (CB-CT). We measured volumetric and anatomical changes in the posterior airway space (PAS) between upright and supine positioning in a three-dimensional set up., Materials and Methods: Coherent CT and CB-CT scans of 55 patients were included in the study. Using Brainlab ENT 3.0, image data was superimposed, and three-dimensional models were segmented. PAS height, cross-sectional area, vertical and horizontal position of the mandible and hyoid, and volumetric analyses of the three-dimensional models were measured., Results: PAS height and cross-sectional area were significantly higher in CB-CT compared to CT scans (p < 0.001). In the vertical dimension, the mandible and hyoid were localized more caudally in CB-CT in contrast to CT scans (p < 0.04; p < 0.001). Three-dimensional evaluation showed a greater volume of the PAS in CB-CT (p < 0.0001). Pearson correlation coefficient showed a correlation between vertical positioning of the mandible and hyoid compared to the positioning of the patient., Conclusions: Patient positioning during CT and CB-CT has an effect on the location of anatomical structures like the mandible and hyoid and changes the dimensions and volume of the posterior airway space significantly., Clinical Relevance: The radiological technique used and the positioning of the patient should be taken into account when considering further surgical therapy.

The objective of this project was to retrospectively evaluate changes in volume of different compartments of the upper airway in response to maxillary, mandibular, and bimaxillary advancement surgeries and to predict the extent of volumetric changes associated with these surgical movements. Pre- and post-surgical cone beam computed tomography scans of 36 patients were evaluated for changes in nasal cavity, nasopharyngeal, oropharyngeal, and hypopharyngeal compartments. The amount of movement for each surgery was measured from skeletal landmarks to reference planes and was correlated with volumetric changes. Maxillary advancement of 4.0±2.2mm increased the oropharyngeal volume significantly (41.40%), and mandibular advancement of 3.8±1.6mm also significantly increased the oropharyngeal volume (21.17%). Bimaxillary advancement of 5.1±1.3mm for the maxilla and 6.4±3.1mm for the mandible significantly increased nasopharyngeal (27.45%), oropharyngeal (66.39%), and hypopharyngeal (52.48%) volumes. Furthermore, for every millimeter anterior movement, oropharyngeal volume increased by 2319.2±771.8mm 3 . Bimaxillary advancement showed a greater increase than isolated maxillary and mandibular advancement in all pharyngeal compartments. Every millimeter of advancement in the bimaxillary group led to a significant increase in oropharyngeal volume, while every millimeter downward movement showed a significant increase in nasopharyngeal volume., (Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Background: Upper airway analysis is an often-cited use of CBCT imaging by orthodontists; however, the reliability of airway measurements using this technology is not fully established., Objective: To determine the intra-examiner and inter-examiner reliability of the complete process of volumetric and cross-sectional area assessments of the upper airway using CBCT imaging., Materials and Methods: Six examiners of varying levels of education and clinical experience performed the steps necessary for airway analysis, including manual orientation, slice and threshold selection and measured nasopharyngeal, oropharyngeal, hypopharyngeal and total upper pharyngeal airway volumes in addition to minimum cross-sectional area on the CBCT images of 10 patients. All measurements were repeated after 4-weeks. Intra- and inter-examiner reliability was calculated using ICC and 95% CI., Results: Threshold selection showed poor intra- and poor inter-examiner reliability, whereas minimum cross-sectional area showed moderate intra- and poor inter-examiner reliability. Intra-examiner reliability of volumetric measurements varied based on the region assessed with ICC ranging from 0.747 to 0.976, and was worst for hypopharynx and best for the oropharynx. Inter-examiner reliability of volume measurements was generally lower, with ICC ranging from 0.175 to 0.945, and was worst for nasopharynx and best for the oropharynx., Conclusions: This study, for the first time, assessed the reliability of upper airway analysis with CBCT when all steps of image processing and measurement are performed by each examiner. Reliability improved with examiner experience, though was generally low for the hypopharynx and nasopharynx volumes and overall minimal cross-sectional area. The oropharyngeal volume was the only parameter to have excellent intra- and inter-examiner reliability.

The present study aims to identify the anatomical functional changes of the buccopharyngeal space in case of singers with canto voice. The interest in this field is particularly important in view of the relation between the artistic performance level, phoniatry and functional anatomy, as the voice formation mechanism is not completely known yet. We conducted a morphometric study on three soprano voices that differ in type and training level. The anatomical soft structures from the superior vocal formant of each soprano were measured on images captured using the Cone-beam Computed Tomography (CBCT) technique. The results obtained, as well as the 3D reconstructions emphasize the particularities of the individual morphological features, especially in case of the experienced soprano soloist, which are found to be different for each anatomical soft structure, as well as for their integrity. The experimental results are encouraging and suggest further development of this study on soprano voices and also on other types of opera voices., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Background: Craniofacial skeletal patterns change after orthognathic surgery. The present study aimed to investigate the effects of different craniofacial patterns on nasal respiratory function and the upper airway., Methods: Forty-seven healthy subjects were selected and divided into 3 groups according to their mandibular position. Sixteen were in the skeletal Class I group, 15 were in the skeletal Class II group, and 16 were in the skeletal Class III group. Cone beam computed tomography was performed, and nasal airflow and nasal resistance were measured. Differences in nasal respiratory functions and upper airway were compared among the groups. A correlation analysis was conducted for nasal respiratory function, upper airway, and skeletal patterns., Results: There were significant differences among the 3 groups regarding dominant-side nasal inspiratory capacity (P = 0.001), bilateral nasal inspiratory capacity (P = 0.005), nasal partitioning ratio-inspiration (P = 0.007), and velopharyngeal minimum cross-sectional area (P = 0.029). The values were significantly higher for the skeletal Class III group than the skeletal Class I and II groups. A correlation analysis showed that the nasal partitioning ratio and nasal airway resistance were mostly negatively correlated with SNA, but the upper airway volume and cross-sectional area were positively correlated with SNB and negatively correlated with ANB. The dominant-side nasal expiratory capacity was mainly negatively correlated with the mean velopharyngeal cross-sectional area (r = -0.324, P = 0.026), mean glossopharyngeal cross-sectional area (Glosso-A mean) (r = -0.293, P = 0.046), and mean total airway cross-sectional area (Total-A mean) (r = -0.307, P = 0.036)., Conclusion: Craniofacial skeletal morphology may affect nasal respiratory function and the upper airway.

Purpose: The objective of this study was to analyze the potential of using low-dose volumetric computed tomography (CT) during different phases of respiration for identifying patients likely to have severe obstructive sleep apnea (OSA), defined as a respiratory disturbance index (RDI) higher than 30., Patients and Methods: A prospective study was undertaken at the Ramathibodi Hospital (Bangkok, Thailand). Patients with diagnosed OSA (N = 82) were recruited and separated into group 1 (RDI, ≤30; n = 36) and group 2 (RDI, >30; n = 46). The 2 groups were scanned by low-dose volumetric CT while they were 1) breathing quietly, 2) at the end of inspiration, and 3) at the end of expiration. Values for CT variables were obtained from linear measurements on lateral scout images during quiet breathing and from the upper airway area and volume measurements were obtained on axial cross-sections during different phases of respiration. All CT variables were compared between study groups. A logistic regression model was constructed to calculate a patient's likelihood of having an RDI higher than 30 and the predictive value of each variable and of the final model., Results: The minimum cross-sectional area (MCA) measured at the end of inspiration (cutoff point, ≤0.33 cm 2 ) was the most predictive variable for the identification of patients likely to have an RDI higher than 30 (adjusted odds ratio [OR] = 5.50; 95% confidence interval [CI], 1.76-17.20; sensitivity, 74%; specificity, 72%,), followed by the MCA measured at the end of expiration (cutoff point, ≤0.21 cm 2 ; adjusted OR = 3.28; 95% CI, 1.05-10.24; sensitivity, 70%; specificity, 68%)., Conclusion: CT scanning at the ends of inspiration and expiration helped identify patients with an RDI higher than 30 based on measurement of the MCA. Low-dose volumetric CT can be a useful tool to help the clinician rapidly identify patients with severe OSA and decide on the urgency to obtain a full-night polysomnographic study and to start treatment., (Copyright © 2018. Published by Elsevier Inc.)

Introduction: The purpose of this article was to evaluate the pharyngeal space volume, and the size and shape of the mandible and the hyoid bone, as well as their relationships, in patients with different facial types and skeletal classes. Furthermore, we estimated the volume of the pharyngeal space with a formula using only linear measurements., Methods: A total of 161 i-CAT Next Generation (Imaging Sciences International, Hatfield, Pa) cone-beam computed tomography images (80 men, 81 women; ages, 21-58 years; mean age, 27 years) were retrospectively studied. Skeletal class and facial type were determined for each patient from multiplanar reconstructions using the NemoCeph software (Nemotec, Madrid, Spain). Linear and angular measurements were performed using 3D imaging software (version 3.4.3; Carestream Health, Rochester, NY), and volumetric analysis of the pharyngeal space was carried out with ITK-SNAP (version 2.4.0; Cognitica, Philadelphia, Pa) segmentation software. For the statistics, analysis of variance and the Tukey test with a significance level of 0.05, Pearson correlation, and linear regression were used., Results: The pharyngeal space volume, when correlated with mandible and hyoid bone linear and angular measurements, showed significant correlations with skeletal class or facial type. The linear regression performed to estimate the volume of the pharyngeal space showed an R of 0.92 and an adjusted R 2 of 0.8362., Conclusions: There were significant correlations between pharyngeal space volume, and the mandible and hyoid bone measurements, suggesting that the stomatognathic system should be evaluated in an integral and nonindividualized way. Furthermore, it was possible to develop a linear regression model, resulting in a useful formula for estimating the volume of the pharyngeal space., (Copyright © 2018 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: The aim of this study was to examine the total volume and cross-sectional areas of the pharyngeal airway after bilateral condylar replacement and mandibular advancement surgery., Materials and Methods: A total of 137 patients (126 women and 11 men) underwent bilateral temporomandibular joint total joint replacement performed by 1 surgeon. A subsample of 30 patients who underwent condylar replacement and only mandibular advancement were evaluated for impact on the airway. Measurements were taken preoperatively, postoperatively, and at a follow-up 1 year after surgery on cone beam computed tomography scans. InVivoDental 3-dimensional imaging (Anatomage, San Jose, CA) was used to measure airway space regarding total volume (in cubic centimeters); minimum cross-sectional area (in square millimeters); minimum cross sections of the first, second, and third cervical vertebrae; and whether the patient had mandibular retrognathia before surgery. A second operator was used to test for interoperator error. Descriptive and bivariate statistics were computed, and the P value was set at .05., Results: There was a significant increase in all measurements at the follow-up visit compared with the preoperative visit. There were no significant differences between groups based on simultaneous Le Fort I surgery, mandibular retrognathia, and gender. However, there were statistically significant differences in cross sections 1 and 2, as well as minimum cross-sectional area, regarding age. Condylar replacement and mandibular advancement have a significant association with an increase in airway space. The intraclass correlation coefficient showed excellent agreement between interoperator measurements., Conclusions: Patients undergoing bilateral temporomandibular joint replacement and mandibular advancement surgery showed an increase in pharyngeal airway space at a 1-year follow-up. In this study, age was significantly associated with the cross-sectional areas of the airway, with older patients having smaller values., (Copyright © 2018 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives: No consensus exists on the assessment of airway in CBCT scans. Two-dimensional measures remain the standard in the cephalometric analysis. This research aimed to evaluate linear and area measurements in two-dimensional views from specific airway regions of interest and compare these to the correspondent volume in CBCT exams., Materials and Methods: 250-selected CBCT scans were retrospectively analyzed. A trained and calibrated examiner performed the linear, area and volume measurements in specific sites for nasal cavity, nasopharynx and oropharynx compartments. Dolphin Software was used for the analysis. The correlations were performed using Pearson coefficient., Results: The highest positive correlations were observed in the nasopharynx and oropharynx sagittal areas and the most constricted area in the oropharynx. Nasopharynx linear measures and nasopharynx coronal area did not present correlation with whole volume. Two-dimensional measurements in the soft palate (width and sagittal area) showed very low positive correlations. Although nasal cavity presented highest volume means, changes in oropharynx contributed more to variations in total volume, compared with the other two sections., Conclusion: Airway sagittal areas, as well as the most constricted axial area in oropharynx remains a useful guide to correlate with airway volume in two-dimensional images.

Purpose: To evaluate the short- and long-term impact of mandibular-only advancement on pharyngeal airway space (PAS) changes by using cone-beam computed tomography (CBCT) and a new segmentation software. Furthermore, to determine whether a correlation exists between forward movement and PAS gain., Materials and Methods: A retrospective evaluation of a homogeneous cohort of Class II patients who had undergone mandibular-only advancement was performed. Pre- (T0), post- (T1), and 1-year post-operative (T2) CBCT scans were obtained in each case, and the changes in PAS parameters (volume and smallest cross-sectional area) were compared with new segmentation software. Mandibular advancement was measured and correlated with PAS parameters., Results: A significant postoperative gain in all airway parameters compared with baseline was shown for T1 (p = 0.02), with an additional increase for T2 (p < 0.001). No significant linear association between the movement of the measurement points and any other PAS parameters could be discerned (p > 0.05)., Conclusion: Our findings indicate that bilateral mandibular-only advancement surgery results in a significant widening of the PAS in Class II patients. Long-term adaption of the PAS also occurs after surgery implying an additional gain of PAS over time. Sicat Air® software seems to be a sufficient and promising tool for PAS evaluation., (Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Purpose: We hypothesized that 3-dimensional changes in the upper airway of patients with skeletal Class III malocclusion are different after mandibular setback and maxillary advancement (MSMA) compared with mandibular setback (MS) and that upper airway changes and the amount of jaw movement are correlated., Patients and Methods: Skeletal Class III patients who underwent MS surgery or MSMA surgery were included in this retrospective cohort study. Cone beam computed tomography scans were acquired before and 3 months after surgery. Changes in the upper airway space were assessed as primary outcome variables. All cone beam computed tomography scans were imported into Dolphin Imaging software (version 11.7; Dolphin Imaging & Management Solutions, Chatsworth, CA) for reconstruction. SPSS software (version 22.0; IBM, Armonk, NY) was used for comparisons of the preoperative and postoperative changes within and between the groups, with analysis of correlations between upper airway changes and the amount of jaw movement., Results: The study included 29 patients (13 in MS group and 16 in MSMA group). In the MS group, the velopharynx, glossopharynx, laryngopharynx, and total upper airway were significantly narrower after orthognathic surgery (P < .05). In the MSMA group, the velopharynx was significantly narrower after surgery (P < .05) whereas no statistically significant constriction was found in the other parts of the upper airway (P > .05). The velopharyngeal, glossopharyngeal, laryngopharyngeal, and total upper airway space in the MS group decreased significantly more than that in the MSMA group (P < .05)., Conclusions: The upper airway was constricted more after MS surgery than after MSMA surgery. From the perspective of upper airway changes, MSMA leads to better outcomes than solely MS., (Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Introduction: In this study, we investigated volumetric and dimensional changes to the pharyngeal airway space after isolated mandibular setback surgery for patients with Class III skeletal dysplasia., Methods: Records of 28 patients who had undergone combined orthodontic and mandibular setback surgery were obtained. The sample comprised 17 men and 11 women. Their mean age was 23.88 ± 6.57 years (range, 18-52 years). Cone-beam computed tomography scans were obtained at 3 time points: before surgery, average of 6 months after surgery, and average of 1 year after surgery. Oropharyngeal, hypopharyngeal, and total volumes were calculated. The lateral surface and anteroposterior dimensions at the minimal axial areas for oropharyngeal and hypopharyngeal volumes and mean mandibular setback were determined., Results: The mean mandibular setback was 9.93 ± 5.26 mm. Repeated measures analysis of variance determined an overall significant decrease between the means for 6 months and up to 1 year after surgery for oropharyngeal and hypopharyngeal volumes, anteroposterior at oropharyngeal, lateral surface at oropharyngeal, and anteroposterior at hypopharyngeal. No strong correlation between mandibular setback surgery and pharyngeal airway volumes or dimensions was determined., Conclusions: After mandibular setback surgery, pharyngeal airway volume, and transverse and anteroposterior dimensions were decreased. Patients undergoing mandibular setback surgery should be evaluated for obstructive sleep apnea and the proposed treatment plan modified according to the risk for potential airway compromise., (Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Obstructive sleep apnoea (OSA) is a sleep-related breathing disorder, characterized by repetitive airway obstructions, causing disruptive snoring and daytime sleepiness. Maxillomandibular advancement (MMA), which enlarges the upper airway, is a therapeutic surgical approach. However, no study has performed an upper airway sub-region analysis using validated three-dimensional (3D) anatomical and technical limits on cone beam computed tomography (CBCT). Hence, this prospective, observational trial was performed to evaluate 3D volumetric changes in the upper airway according to validated 3D cephalometric landmarks, before and after MMA, for all patients with a polysomnography diagnosis of OSA (apnoea-hypopnoea index (AHI) ≥5). The secondary objective was to evaluate the impact of MMA on the AHI and in a subjective manner with the Epworth Sleepiness Scale (ESS) and OSA questionnaire. Eleven consecutive OSA patients were included. A significant volume increase in the oropharynx (P=0.002) and hypopharynx (P=0.02) was observed, in contrast to a non-significant volume reduction in the nasopharynx (P >0.05). The median AHI (P=0.03) and ESS score (P=0.004) decreased significantly as a result of surgery. In conclusion, MMA significantly enlarges the airway volume of the oropharynx and hypopharynx and is associated with improved quality of life., (Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Objectives: To develop and validate a new reproducible 3D upper airway analysis based on skeletal structures not involved in the modification, which occur during orthognathic surgery., Methods: From retrospective cohort of orthognathic surgically treated patients, pre- and postsurgical CBCT-scans of 10 post-pubertal patients were randomly selected. Two operators identified the landmarks, calculated the airway volumes, cross sections and linear measurements on the 10 scans twice at two different time intervals. Statistical analysis included test for normal distribution, technical error measurements, and intra- and inter-observers reliability., Results: Intra- and inter-observer reliability was excellent for volumes and cross sections. The entire data sets exhibited normal distribution. Technical error of measurements showed an error in the range of 1.6 to 10.2% for volume, 1.6 to 12.2% for cross-sectional measurements, and 0.3 to 2.5% for linear measurements. No systematic errors were detected., Conclusions: This new proposed definition of upper airway boundaries was shown to be technical feasible and tested to be reliable in measuring upper airway in patients undergoing orthognathic surgery.

Objectives: The purpose of the study was to test the intra and interobserver reliability of manual volumetric segmentation of pharyngeal and sinonasal airway subregions., Study Design: Cone beam computed tomography data of 15 patients were collected from an orthodontic clinical database. Two experienced orthodontists independently performed manual segmentation of the airway subregions. Four performance measures were considered to test intra and interobserver reliability of manual segmentation: (1) volume correlation, (2) mean slice correlation, (3) percentage of volume difference, and (4) percentage of nonoverlapping voxels., Results: Intra and interobserver reliability was observed to be greater than 0.96 for the entire pharyngeal and sinonasal airway sinus subregions by both observers using the volume correlation method. Mean slice correlation was found to be greater than 0.84, showing the existence of nonoverlapping voxels. Therefore, the percentage of nonoverlapping voxels was used as a reliability measure and was found to be less than 20% for both intra and interobserver markings., Conclusions: The mean slice correlation and percentage of nonoverlapping voxels were the most reliable performance measures of segmentation correctness. Volume correlation and the percentage of volume difference were observed to be the most reliable performance measures for volume correctness., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To evaluate pharyngeal airway space (PAS; nasopharyngeal, oropharyngeal, and total airway) volume and the correlation of an obstructive sleep apnea (OSA) and hypopnea syndrome screening questionnaire (STOP-BANG) with various mandibular setbacks during bimaxillary surgery and compare these findings with an age- and gender-matched skeletal Class I control group., Patients and Methods: This retrospective cohort study was composed of patients with skeletal Class III discrepancy who underwent bimaxillary jaw surgery and were assessed with STOP-BANG score, cephalometry, and cone-beam computed tomography (of the PAS). The predictor variable was bimaxillary jaw surgery and included 4-, 6-, and 8-mm setbacks. The primary outcome variables were PAS volume, body mass index, and STOP-BANG score evaluated at 1 week before surgery and after comprehensive orthodontic treatment (11.25 ± 1.95 months). Other variables were grouped into the following categories: demographic and cephalometric parameters. Statistical intragroup and intergroup differences were assessed by paired t and independent t tests (P < .05), respectively., Results: The study sample was composed of 48 patients (18 to 25 yr old); group I received 4-mm setback (n = 16), group II received 6-mm setback (n = 16), and group III received 8-mm setback (n = 16) mandibular surgery, and all test groups received 4-mm maxillary advancement. The entire study group was compared with a skeletal Class I control group (n = 16). The total PAS volume after orthodontic treatment in groups I and II showed a significant decrease compared with the presurgical PAS (P < .001), but the decrease was not less than that in the control group (P > .05). In contrast, the total PAS volume in group III after orthodontic treatment (23,574 ± 1,394 mm 3 ) was less than that in the control group (23,884 ± 1,543 mm 3 )., Conclusion: After surgery, patients with Class III discrepancy exhibited a decrease in oropharynx volume; however, the STOP-BANG score showed no change in risk factors scores for OSA at 4- to 8-mm setback surgery of the mandible in bimaxillary jaw surgery., (Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Purpose: The objective of the present study was to comparatively evaluate the oropharyngeal space of patients with obstructive sleep apnea syndrome (OSA) and asthma by means of Cone Beam Computed Tomography (CBCT) images., Material and Methods: The study included individuals with OSA and asthma (n=10), with OSA and without asthma (n=6), asthmatics without OSA (n=6) and healthy individuals (n=25). All patients were evaluated by a pneumologist and submitted to a nocturnal polysomnogram. Participants underwent CBCT examinations using an I-CAT ® device (Imaging Sciences International, Hatfield, PA, U.S.A.) and all images were exported to Dolphin Image 3D ® software. Cephalometric measurements were taken, as well as measurements of length (C), volume (VOL), sagittal area (SA) and minimum cross-sectional area (MCA); an evaluation was made of the format and contour of the upper airway in three dimensions, with p<0.05 considered significant., Results: In the results of the present study, a statistically significant difference was found between VOL, SA and MCA (p=0.011; p=0.009; p=0.010) with reduced elevated values among the OSA+Asthma, OSA, Asthma and Control groups. Significant differences were seen between the linear (AP), cross-sectional (TR) and mean transverse area (TA) measurements in the group of patients with OSA and asthma as compared to the control group. In the control group, the greatest narrowing of the airway was observed either in the retroglossal or retropalatal area, while more patients in the experimental groups showed narrowing in the retropalatal area., Conclusion: The condition of OSA+asthma was associated with a substantial reduction in upper airway measurements in comparison to controls., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: Upper airway analysis is an often-cited use of cone beam computed tomography (CBCT) imaging in orthodontics. However, the reliability of this process in a clinical setting is largely unknown., Objective: Our objective was to systematically review the literature to evaluate the reliability of upper pharyngeal airway assessment using dental CBCT., Search Methods: MEDLINE, EMBASE, Web of Science, and Google Scholar were searched through June 2015., Selection Criteria: Human studies that measured reliability of upper airway assessment in patients using CBCT as part of the study protocol were considered., Data Collection and Analysis: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was followed. Data were collected on overall study characteristics and measurements, CBCT unit and machine settings used, and examination characteristics of the included studies. Methodological quality of the included studies was evaluated., Results: Forty-two studies were evaluated, representing the CBCT scans of 956 patients. Studies included a wide variety of patients and CBCT machines with various scan settings. Only five studies were deemed high quality. The available evidence indicates that under specific restricted conditions there is moderate to excellent intra- and inter-examiner reliability. Airway volume demonstrated greater intra- and inter-examiner reliability than did minimum cross-sectional area. However, significant methodological limitations of the current literature, most importantly a lack of manual orientation of the images and selection of threshold sensitivity in study protocols, suggest that reliability has not been adequately established., Conclusions: The current literature reports moderate to excellent reliability, with airway volume having higher reliability than minimum cross-sectional area. However, only limited aspects of the process of airway analysis have been evaluated, indicating that further research is required to adequately establish the reliability of upper pharyngeal airway assessment of patients using dental CBCT., Registration: None., (© The Author 2016. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com)

Objective: To evaluate the pharyngeal airway space changes in complete unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP) individuals, and compare with age and sex-matched noncleft (NC) control subjects., Design: Retrospective study., Setting: Cleft and Craniofacial Centre, KK Women's and Children's Hospital, Singapore., Materials and Methods: Twenty UCLP (mean age: 13.4 ± 0.5 years), 18 BCLP (mean age: 13.5 ± 0.5 years) and 20 skeletal Class I subjects (mean age: 13.4 ± 0.6 years) were included in the study. Cone beam computed tomography scans were assessed for pharyngeal airway space (PAS) (oropharyngeal, nasopharyngeal, total airway space volume), and compared with PAS of age and sex-matched skeletal Class I NC individuals., Results: Pharyngeal airway space showed statistically significant differences in the UCLP, BCLP, and NC control subjects. Oropharyngeal (9338 ± 1108 mm 3 , P < .05), nasopharyngeal (2911 ± 401 mm 3 , P < .05), and total airway space (12 250 ± 1185 mm 3 , P < .05) volumes of BCLP individuals showed significant reduction in comparison to UCLP and NC. There were no gender differences of PAS in any of the groups tested (P > .05)., Conclusion: The pharyngeal airway space was significantly reduced in the BCLP group than were those in UCLP and control groups. This reduced PAS should be taken into account when planning treatment for these individuals.

Objective: To correlate the pharyngeal airway subregions with the positioning of the hyoid bone., Material and Methods: The study examined 107 lateral cephalometric (LC) and cone beam computed tomography (CBCT) images. Linear and volumetric measurements of the pharyngeal subregions were made and correlated to linear measurements using hyoid triangle analysis on images of LC and multiplanar (MPR) and three-dimensional (3D) reconstructions of CBCT., Results: There was significant correlation between linear measurements of the pharyngeal subregions and hyoid bone position in LC images and in MPR and 3D reconstructions of the CBCT. Correlations were more frequent in the oropharynx and hypopharynx, especially for LC images. No correlations were observed between LC images or CBCT reconstructions and the volumetric measurements of the pharyngeal subregions and the position of the hyoid bone., Conclusion: The hyoid bone position showed more correlations with oropharynx and hypopharynx airway measurements. The hyoid triangle method was not applicable to 3D images, since it showed a smaller number of measures correlated to the hyoid bone position.

Objective: The objective of this study was to three-dimensionally evaluate the pharyngeal dimensions of individuals with complete nonsyndromic unilateral cleft lip and palate (UCLP) using cone beam computed tomography., Design: This was a cross-sectional prospective study., Setting: The study took place at the Laboratory of Physiology, Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo, Bauru-SP, Brazil., Patients and Participants: The control group (CON) consisted of 23 noncleft adults with class III malocclusion, and the cleft group (UCLP) consisted of 22 individuals with UCLP and class III malocclusion. Two subgroups of individuals with class III malocclusion as a result of maxillary retrusion with (UCLP'; n = 19) and without (CON'; n = 8) clefts were also assessed., Interventions: Pharyngeal volume, pharyngeal minimal cross-sectional area (CSA), location of CSA, pharyngeal length, sella-nasion-A point angle (SNA), sella-nasion-B point angle (SNB), and A point-nasion-B point angle (ANB), and body mass index were assessed using Dolphin software., Main Outcome Measure: The pharyngeal dimensions of UCLP individuals are smaller when compared with controls., Results: Mean pharyngeal volume (standard deviation) for the UCLP patients (20.8 [3.9] cm 3 ) and the UCLP' patients (20.3 [3.9] cm 3 ) were significantly decreased when compared with the CON (28.2 [10.0] cm 3 ) and CON' patients (29.1 [10.2] cm 3 ), respectively. No differences were found in the pharyngeal minimal CSA, ANB, or pharyngeal length values between groups (CON versus UCLP and CON' versus UCLP'). CSAs were located mostly at the oropharynx, except in the UCLP' patients, which were mainly at the hypopharynx. Mean SNA in the UCLP (76.4° [4.6°]) and UCLP' groups (75.1° [3.1°]) were significantly smaller than those in the CON (82.8° [4.1°]) and CON' groups (78.6° [1.2°]). SNB values were statistically smaller only for the comparison of CON versus UCLP patients., Conclusion: The pharynx of individuals with UCLP and class III malocclusion is volumetrically smaller than that of individuals with class III malocclusion and no clefts.

Surgically assisted rapid maxillary expansion has been used for the treatment of transverse maxillary deficiency. This prospective study aimed to evaluate the effect of this surgery (with or without pterygomaxillary disjunction) on the upper airway volume. The patients were randomly divided into two groups: without pterygomaxillary disjunction (-PD) and with pterygomaxillary disjunction (+PD). Eleven patients per group were estimated to obtain a representative sample (90% of power and 95% of confidence level). Volumetric images of cone beam computed tomography scans were obtained preoperatively, immediately after Hyrax screw stabilization and 6 months after Hyrax screw stabilization. Volumetric measurements of the nasal cavity, maxillary sinuses, nasopharynx, and oropharynx, and of the minimum oropharynx cross-sectional area were obtained using Dolphin 3D Imaging Software. The final sample consisted of 25 adult individuals (+PD group, n=12; -PD group, n=13). In the +PD group, we observed a statistically significant increase immediately after Hyrax screw stabilization for the nasopharynx volume (P=0.003), oropharynx volume (P=0.007) and oropharynx cross-sectional area (P=0.001). Pterygomaxillary disjunction resulted in a significant (P <0.05) increase in volumetric measurements of the nasopharynx and minimum oropharynx cross-sectional area 6 months after the expander device stabilization., (Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Objectives: To examine the influence of negative pressure of the pharyngeal airway on mandibular retraction during inspiration in children with nasal obstruction using the computational fluid dynamics (CFD) method., Setting and Sample Population: Sixty-two children were divided into Classes I, II (mandibular retrusion) and III (mandibular protrusion) malocclusion groups., Material and Methods: Cone-beam computed tomography data were used to reconstruct three-dimensional shapes of the nasal and pharyngeal airways. Airflow pressure was simulated using CFD to calculate nasal resistance and pharyngeal airway pressure during inspiration and expiration., Results: Nasal resistance of the Class II group was significantly higher than that of the other two groups, and oropharyngeal airway inspiration pressure in the Class II (-247.64 Pa) group was larger than that in the Class I (-43.51 Pa) and Class III (-31.81 Pa) groups (P<.001). The oropharyngeal airway inspiration-expiration pressure difference in the Class II (-27.38 Pa) group was larger than that in the Class I (-5.17 Pa) and Class III (0.68 Pa) groups (P=.006)., Conclusion: Large negative inspiratory pharyngeal airway pressure due to nasal obstruction in children with Class II malocclusion may be related to their retrognathia., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: To evaluate the effect of a Herbst appliance on ventilation of the pharyngeal airway (PA) using computational fluid dynamics (CFD)., Materials and Methods: Twenty-one Class II patients (10 boys; mean age, 11.7 years) who required Herbst therapy with edgewise treatment underwent cone-beam computed tomography (CBCT) before and after treatment. Nineteen Class I control patients (8 boys; mean age, 11.9 years) received edgewise treatment alone. The pressure and velocity of the PA were compared between the groups using CFD based on three-dimensional CBCT images of the PA., Results: The change in oropharyngeal airway velocity in the Herbst group (1.95 m/s) was significantly larger than that in the control group (0.67 m/s). Similarly, the decrease in laryngopharyngeal airway velocity in the Herbst group (1.37 m/s) was significantly larger than that in the control group (0.57 m/s)., Conclusion: The Herbst appliance improves ventilation of the oropharyngeal and laryngopharyngeal airways. These results may provide a useful assessment of obstructive sleep apnea treatment during growth.

The aim of this study was to evaluate both the 2-dimensional (2D) and 3-dimensional (3D) configuration of the posterior airway space (PAS) in healthy 239 patients using cone-beam computed tomography (CBCT). In particular, we investigated the correlation between the 2D and 3D measurements in view of the potential impact on diagnosis of upper airway obstruction. The pharyngeal airway of each patient was studied at five levels: the level of the posterior nasal spine (PNS), the level of half-height of the PNS and the tip of the soft palate, the level of the tip of the soft palate, the level of the anterior-inferior point of the second vertebra, and at least the level of the top of the epiglottis. At each of these levels, the anterior-posterior dimension as well as the corresponding cross-sectional area was measured. Furthermore we measured the volume of the whole PAS between the first and the last level and compared it with the corresponding 2D values. Differences between genders and age effects were estimated in an analysis of covariance. P values <.05 were considered significant. Linear models were fitted to find the optimal formula to calculate the area or volume from measured distances. Limits of agreement were calculated as 2 ± residual standard deviations. We generated normal 2D and 3D values of the PAS for a normal population. In regard to age, no significant differences were observed. Significant differences were assessed between healthy males and females; however no correlation was observed between the obtained measurements in 2D axial view and the corresponding cross-sectional areas and mean volume in 3D view. In summary, radiologic imaging is a helpful tool to evaluate the airway space in patients with OSAS. However, drawing conclusions from 2D PAS imaging to assess 3D PAS configuration is not reliable, since there is no sufficient correlation between posterior-anterior distances and the corresponding cross-sectional areas., (Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Objective: To systematically review the literature correlating upper airway parameters between lateral cephalograms (LC) and cone-beam computed tomography (CBCT) or computed tomography (CT) scans to determine the utility of using LC to predict three-dimensional airway parameters., Materials and Methods: Both electronic and manual searches of the included studies were performed by two reviewers, and the quality of the studies that met selection criteria were assessed., Results: A total of 11 studies from the literature met the selection criteria. Assessed outcome variables showed correlation r < .7 between the LC and CT scans. The correlation between the LC and CBCT ranged from weak to strong with -.78 ≤ r and r ≤ .93 reported in the nasopharyngeal segment. In the oropharyngeal segment, a weak to strong correlation was reported with a range of -37 ≤ r and r ≤ .83 between the CBCT and LC. All associations in the hypopharyngeal segment showed a weak correlation. Four of studies were of weak quality, five were of moderate quality, and two were rated to be of strong quality., Conclusion: No strong correlations were reported between the LC and CT scans. However, the LC-derived adenoid-nasopharyngeal ratio and the linear measurement (posterior nasal spine, PNS, to posterior pharyngeal wall) had a strong correlation with upright nasopharyngeal area and volume in the CBCTs. The area measurement in conventional LC can be also used as an initial screening tool to predict the upright three-dimensional oropharyngeal volumetric data. The variability of the hypopharyngeal segment cannot be predicted by LCs. However, more well-designed studies are needed to determine the clinical utility of using LC to predict airway size.

Study Objectives: Although volumetric changes of the upper airway occur following surgical advancement of the maxilla, few studies investigated these changes using three-dimensional imaging techniques. Thus, the goal of this study was to verify whether the surgical advancement of the maxilla affects the volume of the upper airway and to determine any association of these volume changes with sex and age., Methods: Preoperative and postoperative cone-beam computed tomography (CBCT) scans of 14 patients (8 male and 6 female) who underwent maxillary advancement to correct skeletal class III deformities were assessed to determine the postoperative volumetric changes in the upper airway. Preoperative and postoperative airway volume measurements were compared by means of paired t-test, which was also used to compare airway volume between genders. Pearson correlation coefficient was used to verify whether a correlation between age and upper airway volume was present., Results: Maxillary advancement produced significant upper airway volume increases (mean 20.94%, p < 0.05) on nearly half of our sample. However, sex and age did not seem to influence upper airway volume in our sample of skeletal class III patients., Conclusions: Surgical advancement of the maxilla may produce significant volume increases in the upper airway of skeletal class III patients regardless of sex and age., (© 2016 American Academy of Sleep Medicine)