Systemic Factors Affecting Orthodontic Treatment Outcomes and Prognosis - Part 1.

This article explores the intersection of various systemic conditions with orthodontic treatment. Renal diseases, including chronic kidney disease and renal transplant, present challenges such as delayed tooth eruption and gingival overgrowth, necessitating careful orthodontic planning and collaboration with physicians. Liver diseases, particularly hepatitis, heighten the risk of periodontal disease and mandate strict infection control measures during orthodontic procedures. Ehlers-Danlos syndrome poses challenges related to collagen fragility, rapid tooth movement, and orthodontic relapse. Autoimmune diseases like diabetes mellitus and juvenile idiopathic arthritis require tailored orthodontic approaches considering oral complications and joint involvement.

Systemic Factors Affecting Orthodontic Treatment Outcomes and Prognosis-Part 2.

This article explores the various challenges systemic conditions can pose before and during orthodontic treatment. Cardiovascular conditions like infective endocarditis require antibiotic prophylaxis before certain orthodontic procedures are started. Patients with bleeding disorders require special considerations in regards to viral infection risk and maintenance of excellent atraumatic oral hygiene. Orthodontists play an important role in early identification of signs and symptoms of eating disorders and should deal with these patients sensitively. Congenital disorders, craniofacial anomalies, and nutritional deficiencies require special considerations and should be addressed appropriately before orthodontic treatment is started.

The use of clear aligners in orthognathic surgeries: a case series.

Pre- and postoperative fixed orthodontic appliances are the customary and standard practice for patients with treatment planned for undergoing orthognathic surgery. Traditionally, most patients undergoing orthognathic surgeries are in their late teens. Although these patients still compose the greatest pool of the orthognathic surgery population, many patients seek orthognathic surgery later in life. This older patient population often has different concerns and goals than the younger patient population. One of these concerns is often the aesthetic appearance of fixed appliances and the time required to wear these appliances pre- and postoperatively. Today, removable orthodontic appliances consisting of a series of clear aligners have gained immense popularity due to their aesthetic appeal over traditional braces. Additional benefits of removable orthodontic appliances include improved oral hygiene leading to a decreased risk of gingivitis. Whereas clear aligner systems are commonly used in the nonsurgical orthodontic population, there has been limited use of Invisalign in the orthognathic surgery population. In this article, we present a case series of 5 patients who successfully underwent orthognathic surgery using clear aligners for pre- and postoperative orthodontic treatment.

Cross-sectional data accurately model longitudinal growth in the craniofacial skeleton.

Dense, longitudinal sampling represents the ideal for studying biological growth. However, longitudinal samples are not typically possible, due to limits of time, prohibitive cost, or health concerns of repeat radiologic imaging. In contrast, cross-sectional samples have few such drawbacks, but it is not known how well estimates of growth milestones can be obtained from cross-sectional samples. The Craniofacial Growth Consortium Study (CGCS) contains longitudinal growth data for approximately 2000 individuals. Single samples from the CGCS for individuals representing cross-sectional data were used to test the ability to predict growth parameters in linear trait measurements separately by sex. Testing across a range of cross-sectional sample sizes from 5 to the full sample, we found that means from repeated samples were able to approximate growth rates determined from the full longitudinal CGCS sample, with mean absolute differences below 1 mm at cross-sectional sample sizes greater than ~ 200 individuals. Our results show that growth parameters and milestones can be accurately estimated from cross-sectional data compared to population-level estimates from complete longitudinal data, underscoring the utility of such datasets in growth modeling. This method can be applied to other forms of growth (e.g., stature) and to cases in which repeated radiographs are not feasible (e.g., cone-beam CT).

A 3-Dimensional Evaluation of the Effects of Unilateral Vertical Mandibular Distraction Osteogenesis on Airway Volume Among Patients With Hemifacial Microsomia.

OBJECTIVE: The aim of this study was to evaluate the volumetric airway changes using three-dimensional images following unilateral vertical mandibular distraction osteogenesis (uVMD) among patients with hemifacial microsomia (HFM). DESIGN: This retrospective study analyzed cone-beam computed tomography (CBCT) scans of patients with HFM at three different timepoints; pretreatment (T0), posttreatment (T1), and at least 6 months post-distraction (T2). The individuals underwent uVMD between December 2018-Januaray 2021. The nasopharyngeal (NP) volume, oropharyngeal (OP) volume, and the area of maximum constriction (MC) were measured. Wilcoxon signed-rank test was used to compare the airway volumes between T0-T1, T1-T2, and T0-T2. RESULTS: Five patients met the inclusion criteria (mean age = 10.4 years; 1 female, 4 males). Intraclass correlation analysis showed excellent interrater reliability (r > .86, P < .001). Posttreatment, the OP airway volume exhibited a significant mean increase of 56% (P = .043) from T0 to T1, but decreased from T1-T2 by 13%. Likewise, the total airway volume presented with a significant mean increase of 48% between T0-T1 (P = .044), and a decrease of 7% from T1-T2. The changes in the NP airway volume and area of MC were not statistically significant (P > .05), but an increase in the mean values were observed. CONCLUSION: Surgical intervention with uVMD may significantly increase the OP airway volume and the total airway volume among patients with HFM immediately after distraction. However, the statistical significance diminished after six months post-consolidation, but the mean percent change may remain of clinical significance. The NP volume did not seem to show significant changes in response to uVMD.

Craniofacial Orthodontic Experience in CODA-Accredited Orthodontic Residency Programs.

To evaluate orthodontic care for patients with craniofacial anomalies (CFA) by identifying orthodontic residents' preparedness to treat certain conditions and willingness to receive more training in CFA.A 12-question survey was sent through the American Association of Orthodontics (AAO) organization to orthodontic residents. Questions were primarily designed to obtain information on the frequency with which they dealt with patients with CFA in their training, specific craniofacial conditions that orthodontic residents feel comfortable treating.A total of 150 participants out of 1066 responded. Of the 150 responses, 35% were first-year residents, 43% second year, and 22% were third-year residents. Thirty nine percent of residents saw 3 or more CFA patients during their residency followed by 24% that saw no patients with CFA. Forty five percent reported that 1 to 3 hours of lecture time was devoted to CFA per month. Sixty percent felt their training in CFA was not sufficient to feel comfortable treating these patients in practice. Specifically, 62% felt comfortable treating Down syndrome, 84% unilateral cleft lip and/or palate, and 64% bilateral cleft lip and/or palate, while the majority did not feel comfortable treating Pierre Robin sequence (68%), Cleidocranial dysplasia (65%), Crouzon syndrome (75%), Pfeiffer syndrome (80%), Treacher Collins syndrome (76%), Apert syndrome (76%), CHARGE syndrome (84%), and DiGeorge sequence (84%). Seventy eight percent of residents reported that they would like more training in treating craniofacial.Orthodontic residents did not feel comfortable treating patients with CFA. Majority of the residents felt that they would like to learn more about CFA.

Craniofacial growth and morphology among intersecting clinical categories.

Differential patterns of craniofacial growth are important sources of variation that can result in skeletal malocclusion. Understanding the timing of growth milestones and morphological change associated with adult skeletal malocclusions is critical for developing individualized orthodontic growth modification strategies. To identify patterns in the timing and geometry of growth, we used Bayesian modeling of cephalometrics and geometric morphometric analyses with a dense, longitudinal sample consisting of 15,407 cephalograms from 1,913 individuals between 2 and 31 years of age. Individuals were classified into vertical facial types (hyper-, normo-, hypo-divergent) and anteroposterior (A-P) skeletal classes (Class I, Class II, Class III) based on adult mandibular plane angle and ANB angle, respectively. These classifications yielded eight facial type-skeletal class categories with sufficient sample sizes to be included in the study. Four linear cephalometrics representing facial heights and maxillary and mandibular lengths were fit to standard double logistic models generating type-class category-specific estimates for age, size, and rate of growth at growth milestones. Mean landmark configurations were compared among type-class categories at four time points between 6 and 20 years of age. Overall, morphology and growth patterns were more similar within vertical facial types than within A-P classes and variation among A-P classes typically nested within variation among vertical types. Further, type-class-associated variation in the rate and magnitude of growth in specific regions identified here may serve as targets for clinical treatment of complex vertical and A-P skeletal malocclusion and provide a clearer picture of the development of variation in craniofacial form.

Estimating Craniofacial Growth Cessation: Comparison of Asymptote- and Rate-Based Methods.

OBJECTIVE: To identify differences between asymptote- and rate-based methods for estimating age and size at growth cessation in linear craniofacial measurements. DESIGN: This is a retrospective, longitudinal study. Five linear measurements were collected from lateral cephalograms as part of the Craniofacial Growth Consortium Study (CGCS). Four estimates of growth cessation, including 2 asymptote- (GCasym, GCerr) and 2 rate-based (GCabs, GC10%) methods, from double logistic models of craniofacial growth were compared. PARTICIPANTS: Cephalometric data from participants in 6 historic longitudinal growth studies were included in the CGCS. At least 1749 individuals (870 females, 879 males), unaffected by craniofacial anomalies, were included in all analyses. Individuals were represented by a median of 11 images between 2.5 and 31.3 years of age. RESULTS: GCasym consistently occurred before GCerr and GCabs consistently occurred before GC10% within the rate-based approaches. The ordering of the asymptote-based methods compared to the rate-based methods was not consistent across measurements or between males and females. Across the 5 measurements, age at growth cessation ranged from 13.56 (females, nasion-basion, GCasym) to 24.39 (males, sella-gonion, GCerr). CONCLUSIONS: Adolescent growth cessation is an important milestone for treatment planning. Based on our findings, we recommend careful consideration of specific definitions of growth cessation in both clinical and research settings since the most appropriate estimation method may differ according to patients' needs. The different methods presented here provide useful estimates of growth cessation that can be applied to raw data and to a variety of statistical models of craniofacial growth.

Geometric morphometric analysis of growth patterns among facial types.

INTRODUCTION: Extreme patterns of vertical facial divergence are of great importance to clinicians because of their association with dental malocclusion and functional problems of the orofacial complex. Understanding the growth patterns associated with vertical facial divergence is critical for clinicians to provide optimal treatment. This study evaluates and compares growth patterns from childhood to adulthood among 3 classifications of vertical facial divergence using longitudinal, lateral cephalograms from the Craniofacial Growth Consortium Study. METHODS: Participants (183 females, 188 males) were classified into 1 of 3 facial types on the basis of their adult mandibular plane angle (MPA): hyperdivergent (MPA >39°; n = 40), normodivergent (28° ≤ MPA ≤ 39°; n = 216), and hypodivergent (MPA <28°; n = 115). Each individual had 5 cephalograms between ages 6 and 20 years. A set of 36 cephalometric landmarks were digitized on each cephalogram. Landmark configurations were superimposed to align 5 homologous landmarks of the anterior cranial base and scaled to unit centroid size. Growth trajectories were calculated using multivariate regression for each facial type and sex combination. RESULTS: Divergent growth trajectories were identified among facial types, finding more similarities in normodivergent and hypodivergent growth patterns than either share with the hyperdivergent group. Through the use of geometric morphometric methods, new patterns of facial growth related to vertical facial divergence were identified. Hyperdivergent growth exhibits a downward rotation of the maxillomandibular complex relative to the anterior cranial base, in addition to the increased relative growth of the lower anterior face. Conversely, normodivergent and hypodivergent groups exhibit stable positioning of the maxilla relative to the anterior cranial base, with the forward rotation of the mandible. Furthermore, the hyperdivergent maxilla and mandible become relatively shorter and posteriorly positioned with age compared with the other groups. CONCLUSIONS: This study demonstrates how hyperdivergent growth, particularly restricted growth and positioning of the maxilla, results in a higher potential risk for Class II malocclusion. Future work will investigate growth patterns within each classification of facial divergence.

Bias in a blink: Shedding light on implicit attitudes toward patients with a cleft lip.

INTRODUCTION: Previous studies have shown that patients with cleft lip and/or palate may be stigmatized in society. The objective of this study was to use an implicit association test to evaluate the subconscious biases of non-health care providers and orthodontists against patients with a repaired cleft lip (CL). METHODS: Respondents participated in an implicit association test. Pictures of patients with CL and controls were shown to participants, along with terms representing positive and negative attributes. Participants were prompted to match pictures to the attributes. The software algorithm detected whether the participants were more likely to associate CL with positive or negative terms than controls. Demographic information was collected to measure the association between some sociodemographic factors and implicit biases. RESULTS: Of 130 valid participants, 52 were orthodontists and 78 were non-health care providers. The entire sample displayed a significant implicit bias against CL (P <0.001). Overall, orthodontists tended to exhibit slightly higher levels of implicit biases against CL than non-health care providers, but the difference was not significant when controlling for sociodemographic factors (P = 0.34). Females showed significantly lower implicit biases against CL than males (P = 0.046). Spearman correlations showed that older people and those who reported a more conservative political affiliation tended to show slightly higher levels of implicit biases against CL (P <0.007). CONCLUSIONS: Orthodontists and non-health care providers showed moderate but significant levels of implicit biases against patients with clefts. Males, older age groups, and patients with a more conservative political affiliation tended to exhibit slightly higher levels of biases than females, younger people, and those with a more liberal political affiliation.

The Relationship Between Dental Agenesis and Maxillary Hypoplasia in Patients With Cleft Lip and Palate.

ABSTRACT: Both dental agenesis and maxillary growth restriction are well-recognized sequelae in patients with unilateral cleft lip and palate, but their etiology remains controversial. The aim of this study was to evaluate the relationship between hypodontia and maxillary volume. A retrospective review of patients age 6 to 9 with Veau III (unilateral) cleft palate who underwent Cone Beam Computer Tomography in preparation for alveolar bone grafting at 2 major Children's Hospitals between 2010 and 2016 was conducted and serial panoramic radiographs were reviewed. Thirty-eight patients were identified that met inclusion criteria and had adequate imaging. Group 1 ("poor growers") consisted of the bottom 50% of Sella-Nasion-A point minus Sella-Nasion-B point (ANB) angles and Group 2 ("good growers") consisted of the top 50% of ANB angles. Group 1 had a significantly higher mean number of missing teeth (1.58 ±â€Š0.28 missing teeth) compared to Group 2 (0.74 ±â€Š0.23 missing teeth), and significantly lower maxillary volume (12.88 ±â€Š0.61 cm3 versus 15.24 ±â€Š0.88 cm3, respectively). The severity of maxillary hypoplasia in cleft patients increases with increased dental agenesis. These data indicate that intrinsic factors play a significant role in maxillary growth restriction in cleft patients, independent of the sequelae of surgical intervention.

When convenience trumps quality of care: A population-based survey on direct to consumer orthodontics.

INTRODUCTION: Since the introduction of direct to consumer orthodontic (DTCO) products in the last decade, these products have been increasing in popularity among orthodontic patients. The purpose of the current article was to assess the populations' perception of DTCOs and to examine various factors that may influence their decision in choosing treatment with DTCO products. METHODS: A cross-sectional population-based survey was conducted in the United States. The 35-question survey was disseminated through Amazon Mechanical Turk (Amazon.com, Inc, Seattle, Wash), and participants were asked questions about their demographics, their perceptions of DTCOs, orthodontists, and factors that may influence their decision should they decide to pursue orthodontic treatment. Pearson's correlations were conducted to assess the association between various factors and the participants' likelihood to choose DTCO products. RESULTS: A total of 1441 subjects participated in the study. More than 83% of the participants have considered pursuing orthodontic treatment to some extent. Twenty-three percent reported that they would highly likely choose DTCO products. The majority of participants reported convenience to be the greatest benefit of DTCOs, followed by cost. The majority of responses seemed to favor DTCOs. Forty-seven percent reported that the coronavirus disease 2019 pandemic did not affect their preference, whereas 26.6% reported to be more likely to pursue DTCOs because of the pandemic. CONCLUSIONS: The majority of participants seemed to perceive DTCOs as a viable alternative for seeking orthodontic care. Although participants had concerns about the coronavirus disease 2019 pandemic, results showed that the pandemic might not significantly affect the preferences. Orthodontists and their constituent organizations may consider more robust awareness and advocacy campaigns to educate the population about orthodontic treatment and the benefits of pursuing treatment with a trained orthodontist.

Examining the variability of bone and soft tissue morphology in Hemifacial Microsomia: A case series of 8 patients.

AIM OF THE STUDY: Patients with Hemifacial Microsomia (HFM) exhibit highly variable skeletal and soft tissue asymmetries. The purpose of this study was to evaluate soft tissue discrepancies in patients with HFM and correlate them to the skeletal discrepancy. Eight patients were selected and studied retrospectively using 3-dimensional (3D) superimposition and color mapping of the soft and hard tissues. The skeletal and soft tissue facial structures were segmented and mirrored, resulting in a perfectly symmetric skull and face. Original and mirrored 3D models were superimposed. Differences between the affected and normal side were assessed in seven areas: frontal, endocanthion, exocanthion, malar, maxillary frontal, mandibular frontal and gonion area. The correlations between the skeletal and soft tissue asymmetry were evaluated by Pearson correlations. Hard tissue asymmetry ranged from 1.4 mm (Endocanthion) to 5.5 mm (Gonion), while soft tissue asymmetry ranged from 1.5 mm (Endocanthion) to 5.6 mm (Malar). Correlation between skeletal and soft tissue deficiency were highly variable, with the highest correlation at gonion and the lowest at exocanthion. Bone and soft tissue hypoplasia were highly correlated at the gonion and the malar area, while the remaining evaluated areas demonstrated poor correlation between skeletal and soft tissue asymmetries. Future studies will determine if target treatment can reliably improve bone and soft tissue hypoplasia in this area.

Bayesian approach to longitudinal craniofacial growth: The Craniofacial Growth Consortium Study.

Early in the 20th century, a series of studies were initiated across North America to investigate and characterize childhood growth. The Craniofacial Growth Consortium Study (CGCS) combines craniofacial records from six of those growth studies (15,407 lateral cephalograms from 1,913 individuals; 956 females, 957 males, primarily European descent). Standard cephalometric points collected from the six studies in the CGCS allows direct comparison of craniofacial growth patterns across six North American locations. Three assessors collected all cephalometric points and the coordinates were averaged for each point. Twelve measures were calculated from the averaged coordinates. We implemented a multilevel double logistic equation to estimate growth trajectories fitting each trait separately by sex. Using Bayesian inference, we fit three models for each trait with different random effects structures to compare differences in growth patterns among studies. The models successfully identified important growth milestones (e.g., age at peak growth velocity, age at cessation of growth) for most traits. In a small number of cases, these milestones could not be determined due to truncated age ranges for some studies and slow, steady growth in some measurements. Results demonstrate great similarity among the six growth studies regarding craniofacial growth milestone estimates and the overall shape of the growth curve. These similarities suggest minor variation among studies resulting from differences in protocol, sample, or possible geographic variation. The analyses presented support combining the studies into the CGCS without substantial concerns of bias. The CGCS, therefore, provides an unparalleled opportunity to examine craniofacial growth from childhood into adulthood.

A Qualitative Assessment of Bone Mineral Density in Individuals With Hemifacial Microsomia: A Cone-Beam Computed Tomography Study.

OBJECTIVE: The purpose of this study is to utilize cone-beam computed tomography (CBCT) to compare the bone mineral density (BMD) on the affected versus nonaffected side, among individuals with hemifacial microsomia (HFM). METHODS: This retrospective study included 9 patients with HFM. Pretreatment CBCT volumes were imported into Invivo5 software, which was used to measure BMD through Hounsfield units (HU) in 3 regions of the mandible; inferior to the lower lateral incisors, inferior to the first molar and at the ramus inferior to the sigmoid notch. Each region was measured at the buccal cortical bone, lingual cortical bone, and cancellous bone. The densities on the right and left sides were compared by Wilcoxon signed-rank test. RESULTS: Overall, the BMD on the affected side tended to show slightly lower values when compared with the nonaffected side. Differences ranged from 14 HU at the lingual cortical plate of the first molar region to 234 HU at the buccal cortical plate of the ramus region. Differences were only statistically significant at the ramus region for the buccal (P = .002) and lingual (P < .001) cortical plates and at the lower incisor region at the buccal cortical plate (P = .016) and cancellous bone (P = .044). The differences, however, did not seem to be clinically significant. CONCLUSIONS: The current study shows that the quality of bone on the affected side may be slightly reduced but did not seem to be clinically significant. This should be accounted for during surgical and orthodontic planning for patients with HFM.

A novel method for fabricating nasoalveolar molding appliances for infants with cleft lip and palate using 3-dimensional workflow and clear aligners.

INTRODUCTION: Nasoalveolar molding (NAM) was introduced over 20 years ago as adjunctive therapy for the correction of cleft lip and palate. In the current study, we propose a new approach using a digital workflow and 3-dimensional printing to fabricate clear aligner NAM devices. METHODS: A polyvinyl siloxane (PVS) impression of an infant with a unilateral complete cleft lip and palate (UCLP) is acquired and poured, and the stone model is scanned with an intraoral scanner. The stereolithography file is digitized, and the alveolar segments are digitally segmented and moved to the desired final position. The total distance moved is divided into a sequence of 1-1.5 mm increments, creating a series of digital models. The models are 3-dimensionally printed along with button templates to allow free form positioning of the button on each model. A Vacuform machine (Taglus, Mumbai, India) was used to fabricate a 0.040-in aligner for each stage. RESULTS: We present 1 case that was treated successfully with this approach. Appointments for the NAM adjustments were primarily to monitor progress and counseling with less time spent adjusting the appliance. The appointment length was reduced by over 30 minutes. Benefits of the aligner are improved fit, more precise increments of activation, reduced chairside time, and potentially minimized number of visits. CONCLUSIONS: NAM custom aligners may provide similar benefits to the traditional approach while reducing the burden of care by reducing the number of visits and appointment duration. Further studies with a sample and longitudinal observations are needed to investigate the benefits of the proposed digital approach.

Accuracy of Three-Dimensional Upper Airway Prediction in Orthognathic Patients Using Dolphin Three-Dimensional Software.

BACKGROUND: Orthodontists and surgeons have been looking for more accurate methods to predict surgical outcomes in patients with skeletal discrepancies. METHODS: The sample consisted of 20 patients from the surgical clinic of a graduate orthodontic program who had been treated with Le Fort I maxillary movement, bilateral sagittal split osteotomy, with or without genioplasty. All patients had to have preoperative (T0) and at least 6 months postoperative (T1) cone-beam computed tomographies that were imported to Dolphin 3-dimensional (3D) software. The 3D voxel-based superimposition on the cranial base was performed for T0 and T1 to accurately measure the skeletal surgical movements. A virtual orthognathic surgery was performed on T0 to mimic the actual skeletal osteotomies using the treatment simulation tool in Dolphin 3D. A prediction 3D soft-tissue image (Tp) was generated based on the Dolphin virtual skeletal planning. The upper airway was segmented and exported as stereolithography surface files in both T1 and Tp. The measurements of the 3D volume of the airway were calculated and compared among T1 and Tp by using surface superimposition technique. Mean and standard deviations of upper airway volume were compared and correlated using paired t-test. RESULTS: There was no statistically significant difference between the upper airway volume of T1 and Tp. CONCLUSION: Dolphin 3D delivers accurate airway prediction which is an important step in 3D virtual planning.

Comparison of the Pharyngeal Airway Volume Between Patients With Ectodermal Dysplasia and Unaffected Controls: A Cone-Beam Computed Tomography Study.

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 mm2 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 mm2 were almost 3 times greater among ED patients, and the relative risk of an MC of less than 100 mm2 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 mm2, which may be of clinical significance and warrants further investigations with larger samples.