Airway volume for different dentofacial skeletal patterns

Correlation between the three-dimensional hyoid bone parameters and pharyngeal airway dimensions in different sagittal and vertical malocclusions

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.

Novel prediction models for pharyngeal-airway volume based on the cranial-base and midsagittal cross-sectional area of the airway in the pharyngeal region: A cephalometric and magnetic resonance imaging study

OBJECTIVE

The objective of the study was to elucidate the association between cranial base (Bjork-Jarabak analysis), midsagittal cross-sectional area of the airway in the pharyngeal region (MCSA-PR) data and pharyngeal-airway volume (PAV) and develop a model that could help clinicians predict PAV using two-dimensional (2D) data (Bjork polygon and MCSA-PR).

MATERIALS AND METHODS

Pre-treatment lateral cephalometric radiographs and magnetic resonance imaging (MRI) scans of 82 women were categorized into three anteroposterior skeletal groups based on ANB angle: Class I (n = 29), 1.5° ≤ ANB≤5.1°; Class II (n = 26), ANB >5.1°; Class III (n = 27), ANB <1.5°. The Bjork polygon, MCSA-PR data from cephalograms and PAV data from MRI scans were examined. Intergroup comparisons were performed using the Kruskal-Wallis test and one-way analysis of variance (ANOVA), with pairwise comparisons conducted using the Bonferroni-corrected Mann-Whitney U-test for the Kruskal-Wallis test and Bonferroni-corrected multiple comparison test for one-way ANOVA. Forward multiple linear regression was used to create model equations for predicting PAV.

RESULTS

MCSA-PR and anterior (N-S) and posterior (S-Ar) cranial-base lengths were positively correlated with the PAV. We developed four models; three operated at the group level, and one encompassed the entire sample. Notably, all models could effectively explain the variance in the PAV data. The model for the Class I group was the strongest (adjusted R2 = 0.77).

CONCLUSION

Our findings indicate the remarkable potential of the MCSA-PR, N-S and Bjork sum angles (BSA) as predictors of the PAV and the relevance of 2D cephalometric and cranial-base parameters in predicting the three-dimensional (3D) pharyngeal-airway size.

Evaluation of nasolacrimal canal morphology in different facial skeletal relationships

BACKGROUND

Abnormal morphological variations of nasolacrimal canal (NLC) and its lack of understanding contributes to acquired injuries during craniomaxillofacial surgical procedures which leads untoward postoperative complications like nasolacrimal obstruction (NLO) and epiphora.

PURPOSE

The purpose of this study was to determine dimensional and volumetric morphological variations of nasolacrimal canal in various facial skeletal relationships which aid in performing a precise and safe surgery.

MATERIALS AND METHODS

This retrospective cohort study involved dimensional and volumetric analysis of nasolacrimal canal procured from computed tomography scans of 47 individuals grouped as ClassI, Class II and Class III, and unilateral cleft lip and palate (UCLP) groups. The outcome variables included length of NLC, volume of NLC, distance between the inferior orifice of the NLC to nasal floor, distance between inferior orifice of NLC to canine apex and distance between inferior orifice of NLC to central incisor apex. The objectives were to analyse morphological variation of NLC in different facial skeletal relationships and to evaluate the variation with change in facial sides and its relationship with surrounding structures.

RESULTS

Volume of the NLC was found significant in Class I and UCLP population (p < 0.05) with the greatest volume in the UCLP group. The mean linear and volumetric measurements between the right and left sides were found insignificant among all groups. Inferior orifice of NLC from canine apex were farthest in Class III and nearest in the UCLP group (p < 0.05). There was no significant association between outcome variables and skeletal base configuration.

CONCLUSION

NLC demonstrates dimensional and anthropometric variations between different skeletal relationships and this study is inevitable in understanding the probability of NLC injury during maxillofacial surgeries.

Cephalometric Screening Assessment for Superior Airway Space Narrowing-Added Value of Three-Dimensional Imaging

Background: Assessing the morphology of the superior airway space is a crucial diagnostic step in the treatment planning of patients with obstructive sleep apnea syndrome (OSAS) or prior to orthognathic surgery. The aim of this study is to evaluate the necessary scope of a two-dimensional cephalometric assessment and the necessity of three-dimensional imaging in the identification of superior airway space narrowing (SASN). Methods: The computed tomography studies of 100 non-obese, non-OSAS patients were evaluated and analyzed retrospectively. Multiplanar reconstructions were created and underwent cephalometric evaluation. The three-dimensional superior airway morphology was segmented and measured for the minimal cross-sectional area (Amin) and volume (V0). Patients were grouped according to Amin < 80 mm2 and V0 < 12 cm3. Cephalometric parameters (CPs) were analyzed according to Amin and V0 with an unpaired t-test, Pearson correlation, and ROC-curve analysis. Results: The CPs regarding sagittal airway space dimensions (IPAS, MPAS, SPAS) and mandibular body length (GoGn) show the strongest correlation to the three-dimensional minimal cross-sectional area (Amin). The ROC-curve analysis classifying for SASN led to an AUC of 0.86 for IPAS, 0.87 for MPAS, 0.88 for SPAS, and 0.63 for GoGn. Three-dimensional imaging may further improve the diagnostic accuracy in the identification of SASN for IPAS below 13.5 mm, MPAS below 10.2 mm, SPAS below 12.5 mm, and GoGn below 90.2 mm. Conclusions: Two-dimensional cephalometric sagittal airway space diameters and mandibular body length are useful initial screening parameters in the identification of superior airway space narrowing. Nevertheless, as the correlation of two-dimensional cephalometric parameters with three-dimensional upper airway space narrowing is varying and highly dependent on acquisition circumstances, indications for three-dimensional imaging, if possible, in the supine position to evaluate upper airway space morphology should be provided generously, especially in patients with low but normal airway space parameters in two-dimensional cephalometry.

Effect of functional appliances on sleep-disordered breathing in Class II division 1 malocclusion children: Randomized controlled trial

OBJECTIVES

A randomized controlled trial was undertaken to investigate the orthopaedic effect of functional appliances on the pharyngeal airway space and nocturnal breathing of children with skeletal class II due to mandibular retrusion.

MATERIALS AND METHODS

Forty patients were randomized into a 1:1 ratio study (Twin block) group and a control (fixed appliance) group. Each group included equal numbers of boys and girls. Diagnosis with sleep-disordered breathing was not an inclusion criterion. The duration of the trial was 12 months (T0 - T12). Eligibility criteria included skeletal Class II division 1 malocclusion with mandibular retrognathism, SNA ≥82, SNB ≤78, ANB ≥4, overjet ≥6 mm, and patients in circumpubertal stage CVM2 and CVM3. The main outcomes were pharyngeal airway volume, oxygen desaturation index (ODI), and maximum expiratory pressure (MEP), while the secondary outcomes were skeletal and dental changes of the maxilla and mandible. Randomization was accomplished with random blocks of 20 patients with allocation concealed in sequentially numbered, opaque, and sealed envelopes. Blinding was only applicable for data analysis of radiographic measurements and data extracted from the pulse oximeter.

RESULTS

The mean age of the patients was 10 ± 1.5 and 10 ± 1.2 at (T0) for the Twin Block and the control groups, respectively. The changes in the oropharyngeal (2.66 cc and 0.056; P = .03) and nasopharyngeal (1.3 cc and 0.84; P = .053) airway volumes for the Twin block and control groups, respectively, were significantly different for the oropharynx. There was a significant decrease in ODI by [median -3.55 (-5.05 to 0.50); P ≤ .001] and a significant increase [median 45 (0.0-110); P ≤ .001] in MEP for the Twin block group. A significant inverse correlation (r = -.589; P = .006) could be found between the total volume of the oropharynx and ODI. No serious harm was observed.

CONCLUSIONS

The Twin block group showed significant change in oropharyngeal airway volume and improvement of nocturnal breathing.

REGISTRATION

This trial was registered at https://www.

CLINICALTRIALS

gov, registration number NCT04255511.

Numerical simulation of upper airway heat transfer in children with mandibular retrognathia during inspiratory process

Introduction

The human upper airway regulates temperature, but its heating capacity remains unclear when the ambient temperature is low and the airway structure is abnormal. Therefore, the purpose of this study was to evaluate the heat transfer characteristics of the upper airway in patients with mandibular retrognathia, and to quantitatively evaluate the influence of ambient temperature on the temperature field of the upper airway, which could provide a valuable reference for the prediction, diagnosis and treatment of respiratory tract related diseases.

Methods

Two typical ambient temperatures of -10 °C and 20 °C were selected to numerically simulate the air flow and heat transfer synchronization in the upper airway model of mandibular retrognathia under quiet breathing and heavy breathing.

Results and discussion

The results showed that the inspired air could not be sufficiently heated after flowing through the upper airway and main trachea in the two breathing states under low temperature conditions, and the inferior bronchus was more stimulated under the state of heavy breathing. In addition, the vortex flow structure in the upper airway can enhance the convective heat transfer effect in the corresponding area.

Three-dimensional evaluation of the effects of Bionator and Forsus appliances on oropharyngeal airway volume in patients with mandibular retrognathia

OBJECTIVE

To evaluate whether there is a difference between the effects of Bionator and Forsus appliances on airway volume.

METHODS

Forty patients with mandibular retrognathia were divided into two groups. The Bionator appliance was applied to Group 1, while the Forsus FRD EZ2 appliance was applied to Group 2. Three-dimensional images were captured before and after functional appliance use in both groups. Dolphin 3D software was used for airway measurements.

RESULTS

No statistically significant difference was found between the groups in terms of volumetric and area measurements. There was a statistically significant difference between the minimum axial T and O-N border T measurements of the groups.

CONCLUSION

The use of functional appliances may contribute to an increase in oropharyngeal airway dimensions, but there was no difference between the Bionator and Forsus groups in terms of volumetric measurements.

Pharyngeal airway subdivisions in 3-dimensional analysis: Differences between anterior and posterior anatomic boundaries

INTRODUCTION

This study aimed to evaluate if there were differences between anterior and posterior anatomic boundaries used for the 3-dimensional determination of pharyngeal airway.

METHODS

The sample included 150 cone-beam computed tomography scans from healthy patients divided according to (1) age: 6-11, 12-16, and ≥16 years; (2) sex: female and male; (3) anteroposterior skeletal pattern: Class I, II, and III; (4) vertical pattern: brachyfacial, mesofacial, and dolichofacial; and (5) craniocervical inclination (CCI): natural head posture, head flexion, and head extension. Anatomic regions were created to determine the correspondences between structures anteriorly and posteriorly to the pharyngeal airway.

RESULTS

The location of the epiglottis, vallecula, hyoid, C2, and C3 were statistically different according to the CCI, and the location of vallecula, C3, and C4 were different according to sex. However, no statistically significant differences were observed between the frequencies of anterior and posterior anatomic region locations among age and different anteroposterior and vertical skeletal patterns. Posterior landmarks tend to be located below the anterior ones; consequently, the anatomic subregion they define will also be located below.

CONCLUSIONS

Anterior and posterior structures and vertical and anteroposterior skeletal patterns may determine upper airway limits regardless of age. However, the studies must be paired according to sex, and CCI must be standardized.

3D Evaluation of Upper Airway Morphological Changes in Growing Patients with Class II Malocclusion Using Sander Bite Jumping Appliance

Class II malocclusion due to mandibular retrognathia is associated with a posterior positioning of the tongue and the hyoid bone, reducing the oropharyngeal volume. This could be a contributing factor to the development of respiratory and cardiovascular problems. This study evaluates the oropharyngeal volume variation in 13 patients with class II malocclusion undergoing functional orthopedic treatment with Sander Bite Jumping Appliance (SBJ). CBCT scans were performed before treatment (T0) and approximately after 12.5 months (T1): the retropalatal volume and retroglossal volume were quantified in mm3 using a segmentation software. At T1, the retropalatal volume increased in 2523 ± 2088 mm3, and the retroglossal volume increased in 2258 ± 1717 mm3. Both values were statistically significant (p < 0.05). This widening of the airways may allow prevention and treatment of sleep-disordered breathing, including obstructive sleep apnea syndrome.

Effectiveness of functional orthopedic appliances as an alternative treatment among children and adolescents with obstructive sleep apnea: Systematic review and meta-analysis

INTRODUCTION

The objective here was to review the efficacy of functional jaw orthopedic appliances for treating children/adolescents with obstructive sleep apnea (OSA), through correlating the apnea/hypopnea index (AHI) and oxygen saturation (SaO₂) in polysomnography (PSG), in addition to questionnaire scores from the obstructive sleep apnea-18 (OSA-18).

METHODS

The PRISMA 2020 guidelines¹ were followed. A search was conducted in October 2021, with updating to May 2022, in the MEDLINE/PubMed, BVS (LILACS/BBO), ISI, SciELO (Web of Science), COCHRANE, EMBASE, SCOPUS and WHO databases and the gray literature. Data selection and extraction were performed by two independent reviewers, with Cohen kappa testing. All articles included in the meta-analyses showed good quality and low risk of bias. Statistical analyses were performed in the "R" software, using means with standard deviations, and differences in the means were represented graphically in forest plots. Heterogeneity was tested using I², in random-effect models.

RESULTS

From before to after treatment, treated individuals showed improved AHI, SaO₂ and OSA-18 scores². Comparing treated individuals and controls, AHI decreased in treated individuals and increased in controls. For SaO₂, the increase in treated individuals was greater than in controls. For OSA-18, daytime/nighttime symptoms decreased in treated individuals and increased in controls.

CONCLUSION

Functional jaw orthopedic appliances are appropriate and effective for children/adolescents with OSA whose etiology is deficient maxillomandibular growth and development. Functional jaw orthopedics treats the form and function of the stomatognathic system, thereby enhancing quality of life.

PROSPERO REGISTRATION PROTOCOL

CRD42021253341.

Correlation between the three-dimensional maxillomandibular complex parameters and pharyngeal airway dimensions in different sagittal and vertical malocclusions

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.

Analysis of maxillary arch morphology and its relationship with upper airway in mouth breathing subjects with different sagittal growth patterns

OBJECTIVE

This three-dimensional cone beam computed tomography(CBCT) study assessed pharyngeal airway and maxillary arch in mouth breathing subjects with different skeletal classifications and analyzed the factors associated with the upper airway morphological variations in mouth breathing (MB) and nasal breathing (NB) subjects.

METHODS

One hundred and five subjects (52 MB and 53 NB children), divided into three skeletal groups: Class I (1° ≤ ANB° ≤ 5°), Class II (ANB° >5°), and Class III (ANB°<1°). An independent t-test and one-way ANOVA test were utilized in the group analysis of normal distributed data. The linear multiple regression test was applied to create a model for the airway volumes based on the maxillary arch parameters in different skeletal groups.

RESULTS

In three skeletal groups, NB individuals had greater oropharyngeal airway volume (OPV) and total pharyngeal airway volume (TPV) than MB. Maxillary arch parameters of intermolar width (IMW), intercanine width (ICW), and maxillary width of canines (MWC) were larger in NB participants than in MB subjects. In the MB group, we discovered that Class II individuals had lower NPV (nasopharyngeal airway volume) than Class I and Class III. MWC was lower in Class II subjects compared to Class I and Class III in both the NB and MB groups.

CONCLUSION

NB individuals had greater pharyngeal airway and maxillary arch parameters than MB subjects. Our model equation revealed that the inter-molar width (IMW) and palatal area (PA) parameters were the strongest predictors of total pharyngeal airway volume (TPV) in the skeletal Class II and Class I groups.

Associations between snoring and dental sleep conditions: A systematic review

BACKGROUND

It is important for dentists to know if the presence of snoring is associated with the presence of other dental sleep conditions (e.g. obstructive sleep apnea [OSA], sleep bruxism [SB], gastroesophageal reflux disease [GERD], xerostomia and oro-facial pain). If so, dentists could play a significant role in the early recognition and management of these conditions.

OBJECTIVES

This systematic review aimed to: (i) investigate the associations between the presence of snoring and the presence of other dental sleep conditions; and (ii) determine if it is clinically relevant that dentists assess snoring in their population.

METHODS

The literature search was performed in PubMed and Embase.com in collaboration with a medical librarian. Studies were eligible if they employed regression models to assess whether snoring was associated with other dental sleep conditions, and/or investigated the incidence of snoring in patients with other dental sleep conditions and vice versa.

RESULTS

Of the 5299 retrieved references, 36 eligible studies were included. The available evidence indicates that the presence of snoring is associated with higher probabilities of OSA, GERD and headache. Due to limited evidence and conflicting findings, the currently available articles are not indicative of associations between the presence of snoring and the presence of SB and oral dryness.

CONCLUSION

Within the limitations of this study, it can be concluded that the presence of snoring is associated with higher probabilities of OSA, GERD and headache. Therefore, it is clinically relevant that dentists assess snoring in their patient population.

Obstructive sleep apnea: a review for the orthodontist

INTRODUCTION

Obstructive sleep apnea (OSA) affects an important part of the population and is characterized by recurrent total or partial obstruction of the upper airway (UA) during sleep, negatively affecting the quality of life of patients in the short and long terms, and constituting an important public health problem for the society. The field of expertise of orthodontists is closely related to the UA, placing them in a strategic position to diagnose air passage failures and intervene when necessary. Orthodontists, as health professionals, must know how to recognize respiratory problems and manage them appropriately, when indicated.

OBJECTIVE

Thus, this paper aims to review and critically evaluate the related literature, to provide orthodontists with updated knowledge on the diagnosis and therapy related to OSA. Science and technology are constantly evolving; thus, the literature was also reviewed considering new technologies available in consumer-targeted applications and devices for the diagnosis, monitoring, and treatment of sleep-disordered breathing.

Impact of bruxism on craniomandibular morphology: A cone-beam computed tomographic study

OBJECTIVE

The main goal of this work was to address craniomorphological characteristics of patients with bruxism when compared to those without bruxism using cone beam computed tomography (CBCT) imaging.

METHODS

Seventy CBCT images of an equal number (n = 35) of orthodontic patients with and without bruxism (age range, 18-44 years) were retrospectively analyzed. Sagittal evaluation, mandibular shape, and skeletal asymmetry were systematically assessed in both groups.

RESULTS

Significant differences (p < 0.05) were observed between groups for Right Articular Fossa (AF) - Axial Plane (AP) and Left AF - AP (B > NB), Right Gonial Angle (GA), Left GA, Sella-Nasion and Occlusal Plane (B < NB). Age (13%), Condyle-Gonion (18%), AF to AP (67%), and Mental-AP (16%) had the greatest impact on bruxers.

CONCLUSION

In this study, the CBCT 3D image showed significant differences in craniofacial morphology, particularly in the mandibular structure of bruxers compared with non-bruxers.

Correlation of transverse mandibular dimension with naso-pharyngeal and oro-pharyngeal airway using computed tomographic analysis - A retrospective observational study

PURPOSE

The aim of the study was to investigate changes in the naso-pharyngeal and oro-pharyngeal airway with varying degrees of mandibular flare.

METHODS

The investigators implemented a retrospective, observational study including CT data from patients fitting the inclusion criteria. Linear and angular measurements were used to assess the flare and transverse dimension of the mandible, while standard reference planes were used for assessment of airway dimensions. The primary outcome measures were to correlate and quantify the naso-pharyngeal and oro-pharyngeal volumes with mandibular flare. Secondary outcome measures were to study the intra-variable correlation. Significance level was fixed at 5% (α = 0.05).

RESULTS

The sample included CT data from 30 individuals with apparently normal craniofacial skeleton (53% males and 46.7% female with a mean age of 29.53 years). Both nasopharyngeal and oropharyngeal volumes demonstrated moderate positive correlations with inter-condylar width (p = 0.020 and p = 0.038) and inter-condylar angles (p = 0.041 and p = 0.005) respectively. Linear regression modelling demonstrated that for every millimetre increase of the Inter-condylar width, the naso-pharyngeal and oro-pharyngeal airway volume increased by 0.423 cm³ (p = 0.020) and 0.381 cm³ (p = 0.038) respectively, and every degree increase of inter-condylar angle produced an increase the nasopharyngeal and oropharyngeal volumes by 0.376cm³ (p = 0.041) and 0.496cm³ (p = 0.005) respectively.

CONCLUSION

Parameters of mandibular flare demonstrate statistically significant correlation to pharyngeal airway volume, which may be a relevant predictor to evaluate airway in patients undergoing corrective skeletal surgery.

A Comparative Assessment of the Upper Pharyngeal Airway Dimensions among Different Anteroposterior Skeletal Patterns in 7–14-Year-Old Children: A Cephalometric Study

Background: The pharyngeal airway is a crucial part of the respiratory system’s function. Assessing the pharyngeal airway dimensions in different skeletal types is important in the orthodontic treatment of growing patients. The aim of this study was to compare the upper pharyngeal airway dimensions of 7–14-year-old children with different skeletal types. Methods: Three-hundred-sixty-one lateral cephalometric radiographs were grouped based on their skeletal patterns determined by the ANB angle as skeletal type I (n = 123), type II (n = 121), and type III (n = 117). The radiographs were divided into 4 groups: 7/8 YO (7–8 years old), 9/10 YO, 11/12 YO, and 13/14 YO. The cephalometric measurements comprised SNA, SNB, ANB, Ad1-PNS, Ad2-PNS, McUP, and McLP. An ANOVA was used to compare the group results. Results: Significant differences in Ad1-PNS, Ad2-PNS, McUP, and McLP in skeletal types II and III were found between age groups. Most upper pharyngeal airway dimensions in skeletal types II and III children were significantly wider in the 13/14 YO group than in the other age groups. Conclusion: The upper pharyngeal airway dimensions increased age-dependently in 7–14-year-old children, especially in skeletal types II and III. The upper pharyngeal airway dimensions could serve as a guide in differentiating the different skeletal classes in clinical settings.

Three-dimensional evaluation of pharyngeal airway and maxillary arch in mouth and nasal breathing children with skeletal Class I and II

OBJECTIVE

This study aimed to investigate whether the subjects with mouth breathing (MB) or nasal breathing (NB) with different sagittal skeletal patterns showed different maxillary arch and pharyngeal airway characteristics.

METHODS

Cone-beam computed tomography scans from 70 children aged 10 to 12 years with sagittal skeletal Classes I and II were used to measure the pharyngeal airway, maxillary width, palatal area, and height. The independent t-test and the Mann-Whitney U test were used for the intragroup analysis of pharyngeal airway and maxillary arch parameters.

RESULTS

In the Skeletal Class I group, nasopharyngeal airway volume (P < 0.01), oropharyngeal airway volume (OPV), and total pharyngeal airway volume (TPV) (all P < 0.001) were significantly greater in subjects with NB than in those with MB. Furthermore, intermolar width, maxillary width at the molars, intercanine width, maxillary width at the canines, and palatal area were significantly larger in subjects with NB than in those with MB (all P < 0.001). In the Skeletal Class II group, OPV, TPV (both P < 0.05) were significantly greater in subjects with NB than in those with MB. No significant differences in pharyngeal airway parameters in the MB group between subjects with Skeletal Class I and those with Skeletal Class II.

CONCLUSION

Regardless of sagittal Skeletal Class I or II, the pharyngeal airway and maxillary arch in children with MB differ from those with NB. However, the pharyngeal airway was not significantly different between Skeletal Class I and II in children with MB.

Accuracy of convolutional neural networks-based automatic segmentation of pharyngeal airway sections according to craniofacial skeletal pattern

INTRODUCTION

This study aimed to evaluate a 3-dimensional (3D) U-Net-based convolutional neural networks model for the fully automatic segmentation of regional pharyngeal volume of interests (VOIs) in cone-beam computed tomography scans to compare the accuracy of the model performance across different skeletal patterns presenting with various pharyngeal dimensions.

METHODS

Two-hundred sixteen cone-beam computed tomography scans of adult patients were randomly divided into training (n = 100), validation (n = 16), and test (n = 100) datasets. We trained the 3D U-Net model for fully automatic segmentation of pharyngeal VOIs and their measurements: nasopharyngeal, velopharyngeal, glossopharyngeal, and hypopharyngeal sections as well as total pharyngeal airway space (PAS). The test datasets were subdivided according to the sagittal and vertical skeletal patterns. The segmentation performance was assessed by dice similarity coefficient, volumetric similarity, precision, and recall values, compared with the ground truth created by 1 expert's manual processing using semiautomatic software.

RESULTS

The proposed model achieved highly accurate performance, showing a mean dice similarity coefficient of 0.928 ± 0.023, the volumetric similarity of 0.928 ± 0.023, precision of 0.925 ± 0.030, and recall of 0.921 ± 0.029 for total PAS segmentation. The performance showed region-specific differences, revealing lower accuracy in the glossopharyngeal and hypopharyngeal sections than in the upper sections (P <0.001). However, the accuracy of model performance at each pharyngeal VOI showed no significant difference according to sagittal or vertical skeletal patterns.

CONCLUSIONS

The 3D-convolutional neural network performance for region-specific PAS analysis is promising to substitute for laborious and time-consuming manual analysis in every skeletal and pharyngeal pattern.

Cone beam computed tomography volumetric airway changes after orthognathic surgery: a systematic review

The aim of this systematic review was to provide a structured overview of three-dimensional airway volume changes in relation to various orthognathic surgeries. Clinical human studies performing pre- and postoperative three-dimensional airway volume assessments to investigate volumetric changes of the airway after orthognathic surgery were included. Pre-determined inclusion and exclusion criteria were applied in an extensive search of the PubMed, Embase, and Web of Science electronic databases. The cut-off date was set to January 1, 2022. Forty-one articles reporting retrospective and prospective case-control and case series studies were included. All studies were determined to be of medium quality (moderate risk of bias). The included studies were categorized by type of intervention. Pre- and postoperative volumes were extracted from the available data, and volume changes as a percentage of the preoperative levels were calculated. Isolated mandibular setback surgery generally decreased the airway volume. Isolated maxillary or mandibular advancement, bimaxillary advancement, and surgically assisted maxillary expansion generally increased the airway volume in the total airway and oropharynx, among which the effect of bimaxillary advancement surgery appeared most significant. High heterogeneity exists in the terminology and definitions of the airway and its segments. A more uniform methodology for airway volume measurement is needed to provide an insight into the impact on the airway of specific types of surgical intervention. In conclusion, airway volumes are affected after orthognathic surgery, which may be of clinical significance, especially in patients who are predisposed to obstructive sleep apnoea.

Assessment of pharyngeal airway in Korean adolescents according to skeletal pattern, sex, and cervical vertebral maturation: A cross-sectional CBCT study

Objective

To investigate airway volumes using cone-beam computed tomography (CBCT) by skeletal patterns, sex, and cervical vertebral maturation (CVM) stages in Korean adolescents.

Methods

The sample consisted of pretreatment CBCT and cephalograms of 95 adolescents (aged 12–19) obtained out of 1,611 patients examined for orthodontic treatment from 2018 to 2020 in Kyungpook National University Dental Hospital. The samples were classified into two sex groups; three skeletal pattern groups, four chronological age groups and four CVM stages. Nasopharyngeal volumes (NPV), oropharyngeal volumes (OPV), total pharyngeal airway volume (TAV) and minimum cross-sectional area (MCA) measurements were taken from the CBCT. Multiple linear regression analyses to find out which one of the independent variables are good predictors for airway variables. Significant factors were analyzed by two-way multivariate analysis of variance (MANOVA) then multiple comparisons were analyzed using a t-test, and Fisher least significant difference.

Results

Age, sex, CVM, and Sella-Nasion-B point have significant influence on airway variable. Males and females showed similar patterns of change in chronological age groups 1–3; however, males had larger NPV, OPV, and MCA at CVM in group 4. According to CVM stages, males had larger OPV, TAV, and MCA at CVM stage 6 (p-value 0.019, 0.021, 0.015, respectively) and no sex differences at CVM stages 3, 4, and 5.

Conclusions

Skeletal patterns have an effect on airway volume. Sex differences were found in CVM 6.

Restricted upper airway dimensions in patients with dentofacial deformity from juvenile idiopathic arthritis

BACKGROUND

This retrospective, cross-sectional study aimed to assess the pharyngeal airway dimensions of patients with juvenile idiopathic arthritis (JIA) and moderate/severe JIA-related dentofacial deformity (mandibular retrognathia/micrognathia), and compare the results with JIA patients with a normal mandibular appearance and a group of non-JIA patients.

METHODS

Seventy-eight patients were retrospectively included in a 1:1:1 manner as specified below. All patients had previously been treated at the Section of Orthodontics, Aarhus University, Denmark. All had a pretreatment cone beam computed tomography (CBCT). Group 1 (JIA+); 26 JIA patients with severe arthritis-related dentofacial deformity and mandibular retrognathia/micrognathia. Group 2 (JIA-); 26 JIA patients with normal mandibular morphology/position. Group 3 (Controls); 26 non-JIA subjects. Dentofacial morphology and upper airway dimensions, excluding the nasal cavity, were assessed in a validated three-dimensional (3D) fashion. Assessment of dentofacial deformity comprised six morphometric measures. Assessment of airway dimensions comprised nine measures.

RESULTS

Five morphometric measures of dentofacial deformity were significantly deviating in the JIA+ group compared with the JIA- and control groups: Posterior mandibular height, anterior facial height, mandibular inclination, mandibular occlusal inclination, and mandibular sagittal position. Five of the airway measurements showed significant inter-group differences: JIA+ had a significantly smaller nasopharyngeal airway dimension (ad2-PNS), a smaller velopharyngeal volume, a smaller minimal cross-sectional area and a smaller minimal hydraulic diameter than JIA- and controls. No significant differences in upper airway dimensions were seen between JIA- and controls.

CONCLUSION

JIA patients with severe arthritis-related dentofacial deformity and mandibular micrognathia had significantly restricted upper airway dimensions compared with JIA patients without dentofacial deformity and controls. The restrictions of upper airway dimension seen in the JIA+ group herein were previously associated with sleep-disordered breathing in the non-JIA background population. Further studies are needed to elucidate the role of dentofacial deformity and restricted airways in the development of sleep-disordered breathing in JIA.

Evaluation and Correlation Between Pharyngeal Space, Mandible, and Tongue in Two Different Facial Patterns

Introduction:

Respiratory function has a direct relationship with the pharyngeal airway dimension and mandibular morphology. The objective of the present study was to compare and correlate pharyngeal airway, mandibular morphology, and tongue position in hyperdivergent and normodivergent patterns using standard cephalometric radiographs.

Materials and Methods:

A total of 130 individuals with age 13 to 19 years, with no craniofacial skeletal abnormalities, were taken. The individuals were divided into 2 groups based on their Frankfort mandibular angle (FMA). Group I consist of 65 hyperdivergent individuals (34 males, 31 females) with FMA >28. Group II consisted of 65 normodivergent individuals (28 males, 37 females) with FMA >25 to <28. For statistical analysis, variables were analyzed by unpaired t-test, with P value <.05. Correlation between the pharyngeal space and the other variables was analyzed with the Pearson correlation test.

Results:

Upper pharyngeal airway space in hyperdivergent growth pattern exhibited a significant negative correlation with ramus width (r = −0.02 and P = .028). Gonial angle showed a statistically significant inverse correlation with lower pharyngeal airway space (r = −0.398 and P = .029). A-point-nasion-B-point (ANB), saddle angle, posterior tongue space, tongue gap, and pharyngeal airway among normodivergent subjects, showed a statistically significant negative correlation.

Conclusion:

The present study showed a significant relationship between pharyngeal airway space, craniofacial morphology, and tongue position suggesting that narrower airway space may be a causative factor for altered dentofacial skeletal patterns. Reduced ramus width, lowered tongue, and narrower posterior pharyngeal wall might be a balancing mechanism set for morphological imbalance in hyperdivergent pattern.

Evaluation of Skeletal, Dentoalveolar, and Sagittal Airway Changes Induced by the Mandibular Anterior Repositioning Appliance (MARA) in Class II Malocclusion: A Retrospective Controlled Study on Lateral Cephalograms

The aim of the study was to evaluate the changes in skeletal, dentoalveolar, and airway dimensions induced by the mandibular anterior repositioning appliance (MARA) in the treatment of Class II malocclusion. A group of 24 Class II patients treated with MARA was evaluated with lateral cephalograms at the start (13.8 ± 2 years) and at the end of treatment (15.7 ± 1.9 years) and compared with a matched untreated Class II group of 20 subjects selected from the archive of the AOOF Legacy. Statistical comparisons were performed with the Student’s t-test. No significant differences were observed for the sagittal airway dimensions. The MARA group showed a significant improvement of Wits (−1.4 mm; p = 0.009) and ANB angle (−0.6°; p = 0.038), a reduction in the overjet (−1.9 mm; p = 0.001), of the overbite (−1.5 mm; p = 0.005), an improvement of molar relationship (1.8 mm; p = 0.000) and a proclination of the lower incisors (2.7°; p = 0.012). During active treatment, MARA did not produce significant favorable changes in the sagittal airway dimensions in Class II subjects when compared with untreated controls. Clinically, these findings highlighted that MARA was able to provide an effective correction of Class II malocclusion with favorable dentoskeletal changes.

Long-term three-dimensional effects of orthognathic surgery on the pharyngeal airways: a prospective study in 128 healthy patients

OBJECTIVE

To investigate volumetric and circumferential pharyngeal airway space (PAS) changes and stability over time as evaluated with cone beam computed tomography (CBCT) before and after orthognathic surgery 2 years postoperatively.

MATERIALS AND METHODS

One hundred twenty-eight patients underwent bimaxillary orthognathic surgery at the Department of Maxillofacial Surgery of University Hospitals, Leuven, Belgium, were recruited prospectively. Patients were divided into 4 groups based on the amount of mandibular advancement in 5 mm increments (< 0 mm, 0-5 mm, 5-10 mm, or > 10 mm). CBCT data was acquired preoperatively and 1-6 weeks, 6 months, 1 year, and 2 years postoperatively. Patients with a history of maxillofacial trauma or surgery, obstructive sleep apnoea syndrome, or craniofacial anomalies were excluded. Nasopharyngeal, oropharyngeal, and hypopharyngeal PAS volumes and constriction surface areas (mCSA) were measured and compared between each time point with a paired t-test.

RESULTS

The largest significant increase in oropharyngeal volume and mCSA were observed in the 5-10 mm (+ 13.3-21.7%, + 51.3-83.0%)) and > 10 mm (+ 23.3-44.6%, + 92.3-130.0%) mandibular advancement groups. This increase only remained stable 2 years postoperatively in the > 10 mm group. In other mandibular advancement groups, short-term oropharyngeal volume and mCSA increases were noticed, which returned to baseline levels 6 months to 1 year postoperatively.

CONCLUSION

Bimaxillary advancement osteotomy significantly increases oropharyngeal volume and mCSA, which remains stable between 6 months to 1 year postoperatively.

CLINICAL RELEVANCE

Long-term stable volumetric and mCSA enlargements were found with > 10 mm mandibular advancements over a period of 2 years. Return towards baseline levels was observed in the other mandibular advancement groups.

Evaluating Morphology of the Pterygomaxillary Junction and Its Association With the Orbit in Different Facial Skeletal Relationships

PURPOSE

The etiology for blindness after Le Fort I osteotomy is poorly understood. The authors propose that a study of the morphology and anatomical relationship of the pterygomaxillary junction to orbital vital structures may be crucial for understanding the possible etiology.

MATERIALS AND METHODS

This retrospective observational study involved analysis of data procured from computed tomography scans of individuals who were categorized into 4 groups based on their skeletal characteristics: skeletal Class I, II, and III and cleft lip palate (CLP). The outcome variables included i) the height, width, and thickness of the pterygomaxillary junction (PTMJ) which represent its morphology and ii) distance of the PTMJ to the superior orbital fissure and optic canal, to demonstrate its proximity to orbital vital structures. Primary outcome measures were to i) compare variance of the outcome variables across groups, ii) determine association between PTMJ morphology and its proximity to the orbit, and iii) determine association between skeletal morphology and the outcome variables. Data were analyzed using descriptive and inferential statistics to study variance and association.

RESULTS

Forty patients (80 sides) were divided into 4 groups. The CLP group demonstrated maximum height and thickness of the PTMJ, whereas the Class II group demonstrated the minimum (P < .001 and P = .001, respectively). The CLP group demonstrated the closest proximity of the PTMJ to orbital vital structures (P < .001), with Class II being the farthest (P < .001). There was a weak positive correlation between the PTMJ height and its thickness and width, whereas a moderate negative correlation was seen between the PTMJ height and its distance from the optic canal and superior orbital fissures (P < .001).

CONCLUSIONS

Morphology of the PTMJ varies with facial skeletal relationship and also influences the relationship of the PTMJ with the orbital vital structures. This may be critical in understanding the pathophysiology of blindness after Le Fort I osteotomies.

Three-dimensional pharyngeal airway space changes after bimaxillary advancement

INTRODUCTION

The probability of improvement in the upper airway space (UAS) with orthognathic surgery should be considered during the surgical-orthodontic treatment decision, providing not only an esthetic, but also a functional benefit for the patient.

OBJECTIVE

The purpose of this study was to evaluate the 3D changes in the upper airway space after maxillomandibular advancement surgery (MMA).

METHODS

A retrospective analysis of 56 patients, 21 male and 35 female, with a mean age of 35.8 ± 10.7 years, who underwent MMA was performed. Pre- and postoperative cone-beam computed tomography scans (CBCT) were obtained for each patient, and the changes in the UAS were compared using Dolphin Imaging 11.7 software. Two parameters of the pharyngeal airway space (PAS) were measured: airway volume (AV) and minimum axial area (MAA). Paired t-test was used to compare the data between T0 and T1, at 5% significance level.

RESULTS

There was a statistically significant increase in the UAS. Bimaxillary advancement surgery increased the AV and the MAA, on average, by 73.6 ± 74.75% and 113.5 ± 123.87%, respectively.

CONCLUSION

MMA surgery tends to cause significant increase in the UAS; however, this increase is largely variable.

Three-dimensional analysis of upper airway and craniofacial morphology in orthodontic adolescents with Attention Deficit Hyperactivity Disorder (ADHD): A comparative retrospective study

PURPOSE

The aim of this study is to evaluate craniofacial characteristics and upper airway morphology in adolescents with Attention Deficit Disorder with Hyperactivity (ADHD) compared to controls (CON).

MATERIALS AND METHODS

Records from July 2014 to May 2018 of patients who were seeking orthodontic treatment at a single institute and had full pre-treatment orthodontic records including cone-beam computed tomography (CBCT) were reviewed. Comprehensive cephalometric variables were measured to determine craniofacial morphology. Upper airway volume (UAV), minimum cross-sectional area (MCA), and linear measurements were calculated at multiple planes.

RESULTS

A total of 87 adolescents (ADHD, 29; CON, 58) were included in the study. Overall, UAV and MCA in ADHA group were smaller than CON. Statistical significance was evident in airway widths at planes A (P=0.002), C (P=0.042), and D (P<0.001), and airway area at plane D (lower hypopharynx) (P<0.001), with the ADHD group showing narrower widths and area compared to CON. The most common skeletal classification in the ADHD group was sequenced as Class II, Class I then Class III, with percentages of (58.6%), (31%) and (10.3%), respectively. No significant differences were found between the groups for any of the skeletal, dental, and soft tissue cephalometric variables.

CONCLUSIONS

ADHD affected adolescents have similar craniofacial characteristics, but narrower upper airway dimensions compared to controls. Further investigations with larger samples are warranted to further elucidate the relationship between SDB and ADHD.

Pharyngeal airway dimensional changes after orthodontic treatment with premolar extractions: A systematic review with meta-analysis

INTRODUCTION

The objective of this research was to evaluate the effect of orthodontic extraction on the pharyngeal airway volume and Minimum cross-sectional area (MCA) in growing and adult patients.

METHODS

Seven databases, unpublished gray literature, and the references list of the identified articles were electronically searched for relevant studies that met our eligibility criteria. Included studies assessed the effect of dental extraction or sagittal dental movements on pharyngeal airway dimensions. The quality of the included studies was assessed using the methodological index for nonrandomized studies. In addition, a meta-analysis was conducted using the RevMan 5 (Nordic Cochrane Centre, Cochrane Collaboration, Copenhagen, Denmark).

RESULTS

In 7 studies, 268 treated patients with a mean age of 19.1 ± 7.6 years and 342 nonextraction control group subjects with a mean age of 19.3 ± 7.2 years were included. Compared with the control group, no statistically significant difference was found in total, nasopharyngeal, glossopharyngeal, oropharyngeal volume, or MCA (P >0.05) in the extraction group except in oropharyngeal volume in which a statistically significant increase in the volume 0.41 cm³ (95% CI, 0.05-0.80; P = 0.03) was detected. The clinical significance of this increase is questionable. Included studies showed a moderate to high risk of bias.

CONCLUSIONS

There is no strong evidence to support the concept that premolar extractions in bimaxillary protrusion or crowded growing and adult patients reduce either pharyngeal airway volume or MCA. Moreover, as the level of evidence was considered very low for all variables, the magnitude, and direction of the summaries have to be interpreted with caution. Future studies with better quality could significantly affect the direction and strength of the results.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42018089924.

A community detection analysis of malocclusion classes from orthodontics and upper airway data

OBJECTIVE

The interaction between skeletal class and upper airway has been extensively studied. Nevertheless, this relationship has not been clearly elucidated, with the heterogeneity of results suggesting the existence of different patterns for patients' classification, which has been elusive so far, probably due to oversimplified approaches. Hence, a network analysis was applied to test whether different patterns in patients' grouping exist.

SETTINGS AND SAMPLE POPULATION

Ninety young adult patients with no obvious signs of respiratory diseases and no previous adeno-tonsillectomy procedures, with thirty patients characterized as Class I (0 < ANB < 4); 30 Class II (ANB > 4); and 30 as Class III (ANB < 0).

MATERIALS AND METHODS

A community detection approach was applied on a graph obtained from a previously analysed sample: thirty-two measurements (nineteen cephalometric and thirteen upper airways data) were considered.

RESULTS

An airway-orthodontic complex network has been obtained by cross-correlating patients. Before entering the correlation, data were controlled for age and gender using linear regression and standardized. By including or not the upper airway measurements as independent variables, two different community structures were obtained. Each contained five modules, though with different patients' assignments.

CONCLUSION

The community detection algorithm found the existence of more than the three classical skeletal classifications. These results support the development of alternative tools to classify subjects according to their craniofacial morphology. This approach could offer a powerful tool for implementing novel strategies for clinical and research in orthodontics.

Importance in the Occurrence Distribution of Minimum Oropharyngeal Cross-Sectional Area in the Different Skeletal Patterns Using Cone-Beam Computed Tomography

Purpose

Obstructive sleep apnea is a condition involving repetitive partial or complete collapse of the pharyngeal airway, especially in patient with mandibular hypoplasia. The present study investigated the differences between the volume of the oropharyngeal airway and the minimum axial area in three skeletal patterns through the use of cone-beam computed tomography (CBCT).

Materials and Methods

CBCT scans of 147 patients were collected to measure the upper oropharyngeal airway volume (UOV), lower oropharyngeal airway volume (LOV), upper oropharyngeal airway area (UOA), minimum upper oropharyngeal airway area (MUOA), lower oropharyngeal airway area (LOA), minimum lower oropharyngeal airway area (MLOA), anatomical structures (orbitale, Or; porion, Po; pogonion, Pog; hyoid, H; second cervical vertebra, C2; fourth cervical vertebra, C4), and relevant angles. Statistical analysis was performed using analysis of variance and Pearson's test.

Results

Compared with patients in Class II, those in Class III and Class I exhibited a significantly anterior position of H and Pog. The vertical positions of H and Pog revealed no significant difference between the three skeletal patterns. Patients in skeletal Class III exhibited significantly larger oropharyngeal area (UOA, MUOA, LOA, MLOA) and oropharyngeal airway (UOV and LOV) than those in skeletal Class II did. The horizontal position of Pog had a moderately significant correlation with UOA (r = 0.471) and MUOA (r = 0.455).

Conclusion

Patients in skeletal Class II had significantly smaller oropharyngeal airway areas and volumes than those in Class III did. The minimum oropharyngeal cross-sectional area had a 67% probability of occurrence in the upper oropharyngeal airway among patients in Class I and Class II and a 50% probability of occurrence among patients in Class III.

Evaluation of the nasal septum and depth of palatal arch in different facial vertical patterns: A Cone-Beam Computed Tomography Study

OBJECTIVE

The purpose of this study was to evaluate the nasal septum and the depth of posterior palatal arch in the different facial vertical patterns using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

A total of 143 CBCTs were analysed (53 normodivergents, 26 hypodivergents, and 64 hyperdivergents) using the software Real Scan 2.2. On the coronal view, the following measurements were taken, palatal interalveolar length (PIL), palatal arch depth (PAD), maxillopalatal arch angle (MPAA), septal vertical length (SVL), deviated septal length (DSL), and deviated septal curve angle (DSCA). Using the program Stata v16.0, we obtained the mean, standard deviation and median values. The identification of significant differences between facial biotypes was performed using the one-way ANOVA test and H of Kruskal-Wallis test, considering a significance level of 0.05.

RESULTS

The hypodivergent group got the highest PIL and MPAA (49.6mm and 118.1° respectively), with statistically significant differences (P<0.05) between this group and the hyperdivergent group. Statistically significant differences were found by gender for the SNMeGo, PFH, AFH, and the relationship between the facial heights, where the males had the highest values. Additionally, PIL and SVL also had the highest values for males (48.8mm and 63.6mm respectively).

CONCLUSIONS

Patients presenting with greater hyperdivergence have shorter interalveolar distances and smaller maxillopalatal arch angles.

Craniofacial and airway morphology of individuals with oculoauriculovertebral spectrum

OBJECTIVES

The objectives of this study were to characterize the craniofacial and airway morphology of oculo-auriculo-vertebral spectrum (OAVS) individuals using computed tomography (CT) examination.

SETTING AND SAMPLE POPULATION

This sample included individuals in the age range from 5 to 14 years, consisted of a group of 18 OAVS individuals (12 females and 6 males), Pruzansky-Kaban¹ IIB and III and by a paired control group matched by age and sex for comparison of morphometric and airway variables.

MATERIALS AND METHODS

Through the CT examination, airway analysis was performed using Dolphin Imaging® Software, and seven morphometric measurements were performed to evaluate craniofacial morphology by Materialize Mimics® Software. To compare airway and morphometric variables, the control group was used. Student's t test and Mann-Whitney U test were performed to compare differences between the groups.

RESULTS

Statistically significant differences were showed between the control and OAVS groups for the variables: total airway (TA) area, volume and MAA, RP area, RP volume, RP MAA, RG volume, RG MAA, total posterior height diff, Md incl and y-axis asymmetry. Pearson and Spearman's correlation showed mostly moderate correlations between Mand Occlusal canting AS with TA area and RP volume, Ax-Gn with TA area and Hy-C3 with TA volume.

CONCLUSIONS

The OAVS's airway was altered and worse than the control group. Our results suggest that the contralateral side of OAVS individuals is unaffected; however, longitudinal assessments are needed to confirm it. Hyoid bone and postural measures play an important role in interpreting airway features of individuals with and without OAVS.

Volumetric Evaluation of Pharyngeal Airway after Functional Therapy

The aim of this study was to evaluate three-dimensional (3D) effects of Twin-block functional appliance (TB) on the pharyngeal airway by using cone beam computed tomography (CBCT). A total of 30 patients (14 females, 16 males; mean age 12.50 ± 1.23 and 12.83 ± 1.17 years, respectively) with skeletal Class II malocclusion were included in this study and were treated with TB. On the pretreatment (T1) and posttreatment (T2) CBCT scans, volumetric changes in the pharyngeal airway; SNA, SNB, and ANB angles; and bilateral effective mandibular (Co-Gn) and midfacial length (Co-A) were also evaluated. The statistical differences were accessed by Wilcoxon signed-rank tests, and Mann-Whitney U tests were used to analyze the scores of male and female subjects. In this study, an increase was observed in SNB and Co-Gn (p < 0.01) while a decrease in ANB and SNA (p < 0.01 and p < 0.05, respectively) was found. However, increase in midfacial length was not statistically significant (p > 0.05). In the evaluation of volumetric pharyngeal airway changes, statistically significant increases (p < 0.01) in the upper and lower division and total airway volume were determined. Gender differences were insignificant for all measurements (p > 0.05). Volumetric changes in the pharyngeal airway after functional therapy can be successfully evaluated by CBCT images. The anterior repositioning of the mandible by TB increases the mandibular length and pharyngeal airway volume in patients with retrognathic mandible.

Effects of surgical mandibular advancement on the upper airways of adult class II patients: A systematic review with meta-analysis

AIM

To systematically review the effects of surgical mandibular advancement (SMA) regarding changes of the upper airways in adult patients with skeletal Class II malocclusion.

MATERIALS AND METHODS

Five electronic databases were searched up to April 2020. Human studies focusing on the morphology and dimension of the upper airways after SMA were included. 'Quality assessment for Before-After (Pre-Post) Studies' was used to assess the risk of bias of the individual studies. Standard mean differences (SMD) with 95% confidence intervals (CI) were calculated for random effect model meta-analysis. The certainty of evidence was assessed using the GRADE tool.

RESULTS

Twenty cohort studies of only treated patients without control group were eligible for qualitative synthesis, of which 17 were used for quantitative synthesis. Very low certainty of evidence indicated that SMA resulted in significant increase of the volume and of the smallest cross-sectional area (SMC) of the nasopharynx (volume SMD: 1.43, CI: 0.62, 2.24, P = .001, I²  = 87.8%; SMC SMD: 1.53, CI: 0.59, 2.47, P = .001, I²  = 90.5%) and oropharynx (volume SMD: 1.36, CI: 0.37,2.35, P = .007, I²  = 92.1%; SMC SMD: 1.21, CI: 0.11,2.32, P = .032, I²  = 93.1%). Significant augmentation of the distances between the posterior pharynx wall and the uvala (SMD: 0.73, CI: 0.46,0.98, P < .001, I²  = 72.7%), the posterior border of the tongue (SMD: 0.52, CI: 0.21,0.84, P = .001; I² : 60.5%), the gonion (SMD: 1.24, CI: 0.56,1.91, P < .001; I²  = 88.8%) and the epiglottis (SMD: 0.40, CI: 0.06,0.74, P = .033; I²  = 84.8%) were observed.

CONCLUSIONS

Weak evidence suggests enlargement of the upper airways of adult Class II subjects following SMA, with major increases in the oropharynx.

Upper airway changes following high oblique sagittal split osteotomy (HSSO)

The aim of this study was to evaluate volumetric changes of the posterior airway space (PAS) following bimaxillary surgery using a high oblique sagittal split osteotomy (HSSO) of the mandibular ramus. The cone beam CTs of Class II and Class III patients taken before (T0) and 6-12 months after surgery (T1) were analyzed using 3D software (Mimics® Innovation Suite 18.0). The PAS was divided into three segments (superior, middle, inferior) by three planes parallel to the Frankfurt horizontal plane intersecting at the posterior nasal spine, the velum palatinum and the epiglottis. Total (TPAS) and partial volumes (SPAS = superior, MPAS = middle, IPAS = inferior) were calculated. For the 25 Class II patients, a highly significant increase (p<0.001) of the total, middle and inferior airway space (TPAS: +33.6%, MPAS: +43.1%, IPAS: +55.9%) was found, while the increase of the upper airway space was statistically not significant (+5.4%, p = 0.074). For the 28 Class III patients, the total, middle and inferior airway space increased statistically insignificantly (TPAS: +4.6%, p = 0.265, MPAS: +2.7%, p = 0.387, IPAS: +2.8%, p = 0.495), while the increase of the upper airway space was statistically significant (+9.7%, p = 0.010). Bimaxillary orthognathic surgery using the HSSO technique led to a significant increase of PAS for Class II patients and could conserve the PAS for Class III patients.

Effect of functional appliances on the airway in Class II malocclusions

The proximity of the orofacial structures to the upper airway has led to enormous interest in their influence on the airway maintenance mechanism. The recognition of Sleep disorders and the evolution of dental sleep medicine has fueled further interest in the role of orthodontic treatment on the airway particularly in Class II malocclusions. With abundant literature on class II malocclusions and growth modification, it is natural that focus would shift on the effect of functional appliances on the airway. Most studies on the subject show an improvement in the airway in response to functional appliances and these include both two dimensional and three dimensional study of the airway. This review showcases the most significant literature on this field of study against the background of the information that is needed to gauge its clinical relevance.

Effect of Orthopedic Treatment for Class III Malocclusion on Upper Airways: A Systematic Review and Meta-Analysis

The aim of this systematic review is to compare the effect on the upper airways of orthopedic treatment for skeletal Class III malocclusion with untreated controls. Nine databases were searched up to August 2020 for randomized or nonrandomized clinical trials comparing orthopedic Class III treatment (facemask or chin-cup) to untreated Class III patients. After duplicate study selection, data extraction, and risk of bias assessment (Risk Of Bias In Non-randomized Studies - of Interventions [ROBINS-I]), random-effects meta-analyses of Mean Differences (MDs)/Standardized Mean Differences (SMD) and 95% Confidence Intervals (CIs) were performed, followed by the Grading of Recommendations Assessment, Development and Evaluation assessment evidence-quality. A total of 10 papers (9 unique nonrandomized studies) with 466 patients (42.7% male; average age 9.1 years) were finally included. Limited evidence indicated that compared to normal growth, maxillary protraction with facemask was associated with increases in total airway area (n = 1; MD = 222.9 mm²; 95% CI = 14.0-431.7 mm²), total nasopharyngeal area (n = 4; SMD = 1.6; 95% CI = 1.2-2.0), and individual airway dimensions (upper-airway MD = 2.5 mm; lower-airway MD = 2.1 mm; upper-pharynx MD = 1.6 mm; lower-pharynx MD = 1.0 mm; all n = 6). Subgroup/meta-regression analyses did not find any significant effect-modifiers, while the results were retained 2-5 years postretention. Our confidence in these estimates was, however, very low, due to the inclusion of nonrandomized studies with methodological issues. Limited data from 2 chin-cup studies indicated smaller benefits on airway dimensions. Existing evidence from controlled clinical studies on humans indicates that maxillary protraction for skeletal Class III treatment might be associated with increased airway dimensions, which are, however, mostly minor in magnitude.

Associations Among Temporomandibular Joint Osteoarthritis, Airway Dimensions, and Head and Neck Posture

PURPOSE

This study sought to investigate associations among progressive temporomandibular joint osteoarthritis (TMJ OA), airway dimensions, and head and neck posture.

MATERIALS AND METHODS

In total, 114 temporomandibular disorders (TMDs) patients were enrolled. Among 114 patients, 28 had no pathologic bony changes in the TMJ condyles (TMDnoOA), 45 had progressive TMJ OA (TMJOApro), and 41 demonstrated TMJ OA which had not progressed for 12 months (TMJOAnopro). TMJ OA was diagnosed based on the Diagnostic Criteria for TMD axis I. Computed tomography (CT) images and lateral cephalograms were obtained at baseline (T0) and 12 months after treatment (T1). The head and neck posture and airway area in upright position were analyzed using lateral cephalograms whereas airway volume in supine position was determined by 3D reconstructed CT images.

RESULTS

The volume change of the oropharynx in supine position was more prominent in the TMJOApro than in the TMDnoOA but no significant differences in changes in the pharyngeal airway while in upright position were detected. The retrognathic facial profile became more remarkable at T1 in the TMJOApro and TMJOAnopro compared to those at T0. The forward head posture seemed to be progressed in the TMJOApro than in either the TMJOAnopro or TMDnoOA.

CONCLUSION

Progressive TMJ OA may have associations with retrognathia and decreased oropharyngeal airway volume in the supine position but not in the upright position. Progressive TMJ OA may be related with altered head posture in the upright position to compensate for reduced airway dimensions.

A cross-sectional retrospective study of normal changes in the pharyngeal airway volume in white children with 3 different skeletal patterns from age 9 to 15 years: Part 1

INTRODUCTION

This study investigated correlations between airway size and age, sex, and skeletal patterns; identified airway change trends; and measured volumetric norms in children via cone-beam computed tomography.

METHODS

Four hundred twenty nontreated white patients were stratified by age, sex, and anteroposterior skeletal pattern. The nasopharyngeal airway (NPA), oropharyngeal airway (OPA), and total pharyngeal airway (TPA) volumes were delineated on 3-dimensional digital cephalograms. SPSS (SPSS, Chicago, Ill) was used to run an analysis of variance and post-hoc analyses.

RESULTS

The Class III group had significantly larger OPA volumes than Class I and II groups. Male subjects had considerably larger NPA volumes than female subjects. Age was significantly associated with all 3 airway volumes (P <0.05). The young cohort (ages, 9-10 years) had a mean TPA of 11,435.34 ± 484.45 mm³, the middle cohort (ages, 11-13 years) had a mean TPA of 14,152.07 ± 395.46 mm³, and the older cohort (ages, 14-15 years) had a mean TPA of 18,057.99 ± 484.25 mm³.

CONCLUSIONS

An effect of skeletal classification on OPA and a sex effect on NPA were observed. The annual change in the mean of TPA volume decreased in subjects aged 10-12 years, then rebounded until 14 years. TPA change peaked in female subjects 1 year before male subjects.

Evaluation of pharyngeal airway volume for different dentofacial skeletal patterns using cone-beam computed tomography

Background/purpose

Understanding of the three-dimensional airway space in three skeletal patterns is important in orthodontic treatment. This study investigated differences between the volume of pharyngeal airway sections and the smallest cross-sectional area in three skeletal patterns by using cone-beam computed tomography (CBCT).

Materials and methods

The 90 patients were collected to measure total pharyngeal airway volume (TP), velopharyngeal airway volume (VP), glossopharyngeal airway volume (GP), oropharyngeal airway volume (OP), hypopharyngeal airway volume (HP), and the smallest cross-sectional areas (SCA) of the upper respiratory tract as well as other relevant anatomical structures. The mean values differences between classes were analyzed using ANOVA. Pearson's test was used to compare classes in terms of the correlations between different factors.

Results

Patients in skeletal classes I and III exhibited significantly higher SCA values (322.6 mm²and 344.5 mm² respectively) than those in skeletal class II (240.8 mm²). Subjects from skeletal classes I and III exhibited significantly higher values of VP, HP, and OP than those in skeletal class II. Skeletal classes I and III exhibited significantly higher TP values (31190.1 mm³ and 30696.2 mm³, respectively) than those in skeletal class II (22386.0 mm³). Non-significant relationships were discovered between pharyngeal airway and skeletal pattern. Conversely, significant relationships were found between TP and gender, ANB, SNB, hyoid and pogonion positions.

Conclusion

The skeletal class II has smaller airway volume than those in skeletal class I and III. The pharyngeal airway volumes could serve as a guide in differentiating the different skeletal classes in clinical settings.

Evaluation of pharyngeal airway dimensions and hyoid bone position according to craniofacial growth pattern

OBJECTIVE

To compare pharyngeal airway dimensions and hyoid bone position in different craniofacial growth patterns.

METHODS

In total, 611 patients divided into 9 subgroups were compared according to malocclusion classification and vertical growth pattern, and these subgroups were compared in terms of pharyngeal airway and hyoid measurements. A two-way ANOVA test was used to compare the findings of the subgroups.

RESULTS

No significant difference was found for the pharyngeal measurements between the groups (p>0.05). The vertical airway length (PNS-Ep) was significantly shorter in the Class III malocclusion group (p<0.05) and in the hypodivergent group (p<0.05). No statistically significant difference was found between any subgroups in any measurements of the position of the hyoid bone (p>0.05).

CONCLUSION

The pharyngeal airway dimensions and hyoid bone position are similar among individuals in the sagittal direction. The vertical airway length is significantly shorter in Class III and hypodivergent individuals.

Position of the hyoid bone and its correlation with airway dimensions in different classes of skeletal malocclusion using cone-beam computed tomography

Purpose

This study investigated the position of the hyoid bone and its relationship with airway dimensions in different skeletal malocclusion classes using cone-beam computed tomography (CBCT).

Materials and Methods

CBCT scans of 180 participants were categorized based on the A point-nasion-B point angle into class I, class II, and class III malocclusions. Eight linear and 2 angular hyoid parameters (H-C3, H-EB, H-PNS, H-Me, H-X, H-Y, H-[C3-Me], C3-Me, H-S-Ba, and H-N-S) were measured. A 3-dimensional airway model was designed to measure the minimum cross-sectional area, volume, and total and upper airway length. The mean cross-sectional area, morphology, and location of the airway were also evaluated. Data were analyzed using analysis of variance and the Pearson correlation test, with P values <0.05 indicating statistical significance.

Results

The mean airway volume differed significantly among the malocclusion classes (P<0.05). The smallest and largest volumes were noted in class II (2107.8±844.7 mm³) and class III (2826.6±2505.3 mm³), respectively. The means of most hyoid parameters (C3-Me, C3-H, H-Eb, H-Me, H-S-Ba, H-N-S, and H-PNS) differed significantly among the malocclusion classes. In all classes, H-Eb was correlated with the minimum cross-sectional area and airway morphology, and H-PNS was correlated with total airway length. A significant correlation was also noted between H-Y and total airway length in class II and III malocclusions and between H-Y and upper airway length in class I malocclusions.

Conclusion

The position of the hyoid bone was associated with airway dimensions and should be considered during orthognathic surgery due to the risk of airway obstruction.

Evaluation and quantification of airway changes in Class II division 1 patients undergoing myofunctional therapy using twin block appliance

Background

The purpose of the present study was to determine the airway changes in skeletal class II division 1 malocclusion patients with mandibular retrognathism, treated with Twin-Block (TB) appliance.

Methods

Airway assessment was carried for twelve patients (mean age 11.7 ± 1.1 years) who underwent myofunctional therapy using TB appliance for correction of skeletal class II division 1 malocclusion with mandibular retrognathism. Acoustic pharyngometry (AP) was used to assess and quantify the comparative changes in the upper airway, pretreatment and posttreatment.

Results

Data acquired was subjected to appropriate statistical analysis. The paired 't' test was used to compare pre-treatment (T0) and after the positive pterygoid response (T1). TB appliance increased mean minimum airway area by 0.28 ± 0.25 cm² and mean airway by 0.47 ± 0.44 cm² with 95% CI. Posttreatment minimum airway and mean area changes were found to be statistically significant (P-value<0.01).

Conclusion

TB appliance therapy has a positive effect on upper airway and is beneficial for the treatment of sleep-related disorders associated with Class II division 1 malocclusion for achieving positive functional changes, esthetics, and healthier quality of life.

Is There a Correlation Between Airway Volume and Maximum Constriction Area Location in Different Dentofacial Deformities?

PURPOSE

The purpose of the present study was to correlate the airway volume and maximum constriction area (MCA) with the type of dentofacial deformity in patients who required orthognathic surgery.

MATERIALS AND METHODS

The present retrospective cohort study included orthognathic surgery patients selected from the private practice of one of us. The selected cases were stratified into 5 different groups according to the clinical and cephalometric diagnosis of their dentofacial deformity. The preoperative airway volume and anatomic location of the MCA were calculated using the airway tool of the Dolphin Imaging software module (Dolphin Imaging and Management Solutions, Chatsworth, CA) and correlated with the diagnosed dentofacial deformity. Differences in the pretreatment airway volumes and MCA location were compared among the deformities.

RESULTS

The MCA location was more often the nasopharynx for maxillary deficiency and the oropharynx for mandibular deficiency deformities. The nasopharynx volume was significantly smaller statistically (P < .005) for maxillary deficiency plus mandibular excess compared with mandibular deficiency. The hypopharynx volume was significantly smaller statistically (P < .005) for vertical maxillary excess plus mandibular deficiency than for both maxillary deficiency and maxillary deficiency plus mandibular excess. No statistically significant difference was found among the different deformity groups in relation to the mean airway volume (P > .005).

CONCLUSIONS

The location of the airway MCA seems to have a strong correlation with the horizontal position of the maxilla and mandible. The MCA in maxillary deficiencies (isolated or combined) was in the nasopharynx, and the MCA in mandibular deficiencies (isolated or combined) was in the oropharynx. Clinicians should consider these anatomic findings when planning the location and magnitude of orthognathic surgery movements to optimize the outcomes.

Immediate effects of mandibular posterior displacement on the pharyngeal airway space: A preliminary study

Objective

This study aimed to evaluate the immediate effects of mandibular posterior displacement on the pharyngeal airway space (PAS) by using cephalometric evaluations and to investigate how the surrounding structures are schematically involved.

Methods

In this retrospective study, 38 subjects with functional Class III malocclusion and two lateral cephalograms were selected. The first lateral cephalogram was taken with the mandible in the habitual occlusal position, and the second in anterior edge-to-edge bite. Paired t-test was used to analyze changes in the PAS, hyoid bone, tongue, and soft palate, followed by mandibular posterior displacement. Pearson's correlation analysis was used to determine the relationship between the amount of mandibular posterior displacement and other variables.

Results

A statistically significant decrease was observed in the PAS following mandibular posterior displacement. Along with mandibular posterior displacement, the tongue decreased in length (p < 0.001) and increased in height (p < 0.05), while the soft palate increased in length, decreased in thickness, and was posteriorly displaced (p < 0.001). The hyoid bone was also posteriorly displaced (p < 0.05). There was no correlation between the amount of mandibular posterior displacement and the measured variables.

Conclusions

The PAS showed a statistically significant decrease following mandibular posterior displacement, which was a consequence of retraction of the surrounding structures. However, there were individual variances between the amount of mandibular posterior displacement and the measured variables.