Assessment of Upper and Lower Airway Dimensions in Skeletal Class I and Class II Subjects Having Different Growth Patterns - A Cross-Sectional Cephalometric Study.

Objectives: To compare the airway dimensions among subjects having skeletal class I and class II patterns considering their hypodivergent, normodivergent, and hyperdivergent growth patterns and to determine any variations between them. Methods and Materials: The study consisted of 156 pre-treatment lateral cephalograms of subjects aged above 18 years. The sagittal skeletal pattern was used to separate the sample into two groups. Each group was further subdivided into hypodivergent, normodivergent, and hyperdivergent growth patterns. The upper and lower airway dimensions were measured in all the subgroups. The intragroup comparison of class I and class II was performed with 1-way ANOVA and post-hoc test. Using the independent t-test, the upper and lower airways were compared between groups. Results: Comparison of subjects according to the growth pattern showed that vertical growth patterns have statically significantly reduced upper and lower airway dimensions as compared to the average and horizontal growth patterns in both skeletal class I and class II subjects. However, the subjects with skeletal class II hyperdivergent growth patterns have significantly reduced lower airway dimensions than those with skeletal class I having hyperdivergent growth patterns. Conclusion: Individuals with skeletal class I and class II patterns characterized by hyperdivergent growth exhibit reduced upper and lower pharyngeal airways. The sagittal skeletal type also plays a role in influencing the dimensions of the upper and lower airways.

Clinical effects of twin-block combined with maxillary expansion on the upper airway in adolescents with Class II malocclusion.

BACKGROUND: Class II malocclusion, particularly class II division 1, poses a significant orthodontic challenge with implications for both aesthetics and health. This study aimed to explore the impact of twin-block (TB) combined with maxillary expansion treatment (TB-ME) on upper airway dimensions and inflammatory profiles in adolescents with skeletal Class II Division 1 malocclusion in adolescent. METHODS: Ninety-two eligible patients were randomly assigned to two groups: TB-ME treatment and traditional McLaughlin Bennett Trevisi (MBT) straight-wire orthodontic treatment (Control). Cephalometric lateral X-ray scans were conducted before and after treatment to assess skeletal changes, including SNA, ANB, and SNB angles, which are essential to assess the anteroposterior relationships of the maxilla and mandible to the cranial base. We also measured the upper airway volumes and areas. Concentrations of inflammatory factors including intercellular adhesion molecule 1 (ICAM-1), matrix metallopeptidase 2 (MMP2), and interleukin 8 (IL-8) of gingival crevicular fluid analysis (GCF) were detected by enzyme-linked immunosorbent assay. RESULTS: TB-ME treatment induced significant improvement in cephalometric parameters, including a decrease in SNA and ANB angles and an increase in SNB angle. Upper airway volumes and areas increased significantly in both groups, with TB-ME showing greater improvements. GCF analysis revealed a reduction in ICAM-1, MMP2, and IL-8 concentrations in the TB-ME group compared to the Control group. CONCLUSIONS: TB-ME treatment demonstrates multifaceted improvements in skeletal malocclusion, upper airway dimensions, and inflammatory profiles in adolescents with class II division 1 malocclusion, showing the promise of TB-ME in addressing the complexities associated with class II malocclusion.

Effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults: a retrospective cephalometric assessment.

Background: This study aimed to assess the effect of premolar extraction and anchorage type for orthodontic space closure on upper airway dimensions and position of hyoid bone in adults by cephalometric assessment. Methods: This retrospective study was conducted on 142 cephalograms of patients who underwent orthodontic treatment with premolar extraction in four groups of (I) 40 class I patients with bimaxillary protrusion and maximum anchorage, (II) 40 class I patients with moderate crowding and anchorage, (III) 40 class II patients with maximum anchorage, and (IV) 22 skeletal class III patients with maximum anchorage. The dimensions of the nasopharynx, velopharynx, oropharynx, and hypopharynx, and hyoid bone position were assessed on pre- and postoperative lateral cephalograms using AudaxCeph v6.1.4.3951 software. Data were analyzed by the Chi-square test, paired t-test, and Pearson's correlation test (alpha = 0.05). Results: A significant reduction in oropharyngeal, velopharyngeal, and hypopharyngeal airway dimensions was noted in groups I, III, and IV (P < 0.001), which was correlated with the magnitude of retraction of upper and lower incisors (r = 0.6 - 0.8). In group II, a significant increase was observed in oropharyngeal and velopharyngeal dimensions (P < 0.001). A significant increase in nasopharyngeal dimensions occurred in all groups (P < 0.001). Also, in groups I and III, the position of hyoid bone changed downwards and backwards, which was correlated with reduction in airway dimensions (r = 0.4 - 0.6). Conclusion: According to the present results, extraction orthodontic treatment affects upper airway dimensions and hyoid bone position. Maximum anchorage decreases airway dimensions while moderate anchorage increases airway dimensions.

Effects of mandibular advancement devices on upper airway dimensions in obstructive sleep apnea: responders versus non-responders.

STUDY OBJECTIVES: To compare the effects of mandibular advancement device (MAD) therapy on upper airway dimensions between responders and non-responders with mild to moderate obstructive sleep apnea (OSA). METHODS: Thirty-one participants (21 men and 10 women) with a mean ± SD apnea-hypopnea index (AHI) of 16.6 ± 6.7 events/h, and aged 48.5 ± 13.9 years, were included in this study. Polysomnographic recordings and cone beam computed tomography (CBCT) scans in supine position were performed for every participant at baseline and at 3-month follow-up with their MAD in situ. Responders were defined as having ≥ 50% reduction in baseline AHI with a residual AHI < 10 events/h. The primary outcome variable was the minimal cross-sectional area of the upper airway (CSAmin). RESULTS: No significant differences were found between responders (n = 15) and non-responders (n = 16) in age, gender distribution, body mass index, and neck circumference (P = 0.06-0.93), nor in AHI and CSAmin (P = 0.40 and 0.65, respectively) at baseline. The changes of the CSAmin with MAD in situ in the responder group were not significantly different compared to those in the non-responder group (P = 0.06). CONCLUSION: Within the limitations of this study, we conclude that the changes of the upper airway dimensions induced by MADs are not significantly different between responders and non-responders with mild to moderate OSA. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02724865. https://clinicaltrials.gov/ct2/show/NCT02724865.

Comparisons of the effects of two types of titratable mandibular advancement devices on respiratory parameters and upper airway dimensions in patients with obstructive sleep apnea: a randomized controlled trial.

OBJECTIVES: To compare the effects of two types of titratable mandibular advancement devices (MADs), namely MAD-H (allowing limited vertical opening) and MAD-S (allowing free vertical opening), on respiratory parameters and upper airway dimensions in patients with mild to moderate obstructive sleep apnea (OSA). MATERIALS AND METHODS: Patients with mild to moderate OSA (5 ≤ apnea-hypopnea index (AHI) < 30 /h) were randomly assigned to two parallel MAD groups. All MADs were subjectively titrated according to a standardized protocol during a 3-month follow-up. Every patient underwent two polysomnographic recordings, and two cone beam computed tomography scans in supine position: one at baseline and another one after 3 months with the MAD in situ. The primary outcome variables were the AHI in supine position (AHI-supine) and the minimal cross-sectional area of the upper airway in supine position (CSAmin-supine). RESULTS: A total of 49 patients were recruited, and 31 patients (21 men and 10 women) with a mean (± SD) age of 48.5 (± 13.9) years and a mean AHI of 16.6 (± 6.7) /h completed the study. In the per-protocol analysis, there was no significant difference between MAD-H (n = 16) and MAD-S (n = 15) in their effects on AHI-supine (P = 0.14) and CSAmin-supine (P = 0.59). Similar results were found in the intention-to-treat analysis (P = 0.47 and 0.57, respectively). CONCLUSIONS: Within the limitations of this study, we conclude that there is no significant difference in the effects of an MAD allowing limited vertical opening and an MAD allowing free vertical opening on respiratory parameters and upper airway dimensions in patients with mild to moderate OSA. CLINICAL RELEVANCE: MADs allowing limited vertical opening and allowing free vertical opening have similar effects on respiratory parameters and upper airway dimensions in patients with mild to moderate OSA. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02724865. https://clinicaltrials.gov/ct2/show/NCT02724865.

Correlation of Medical Comorbidities and Upper Airway Measurements among Dental Patients at Risk of Developing Obstructive Sleep Apnea.

Obstructive Sleep Apnea (OSA) is a partial or total upper airway collapse resulting in sleep-breathing disturbances. There are many medical comorbidities associated with OSA; hence, this study is important as the prevalence of patients with medical comorbidities associated with OSA is increasing. The study aimed to correlate medical comorbidities and OSA symptoms of the patients along with their upper airway dimensions using Cone Beam Computed Tomography (CBCT) scans to identify patients at risk of developing OSA. This cross-sectional study included patients who had CBCT imaging taken between 2014 and 2020. A questionnaire was used to gather information on patients' medical history and OSA symptoms. The upper airway dimensions of the CBCT scans were evaluated before logistic regression and Fisher's exact test were carried out to determine the relationships between the variables. p ≤ 0.05 was considered statistically significant. Logistic regression revealed an association of longer length (p = 0.016), smaller total volume (p = 0.017) and width (p = 0.010) of upper airways with hypertension. Furthermore, loud snoring was seen in patients with hypertension, heart disease and obesity whereas difficulty concentrating during the day was present in subjects with deviated nasal septum, tonsillitis and depression. For upper airway dimensions, a smaller average volume was associated with loud snoring (p = 0.037), difficulty concentrating during the day (p = 0.002) and mood changes (p = 0.036). A larger anterior-posterior dimension was also associated with excessive daytime sleepiness (p = 0.042), difficulty concentrating during the day (p < 0.001) and mood changes (p = 0.009). Longer airway length was additionally found to be associated with loud snoring (p = 0.021). CBCT taken for dental investigations could be correlated with patients' medical history and OSA symptoms to screen patients at risk of OSA.

Effect of Mandibular Setback Surgery on Tongue Length and Height and Its Correlation with Upper Airway Dimensions.

INTRODUCTION: The changes in length and height of tongue following mandibular setback (MS) surgery may affect pharyngeal airway dimensions. There is limited literature correlating tongue dimensional changes with linear and volumetric airway changes following MS with bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class III patients. MATERIALS AND METHODS: Treatment records of 18 patients who underwent MS with BSSRO were evaluated for changes in tongue and linear airway dimensions, mean airway volume and area at T1 (1-week pre-surgery), T2 (6-month post-surgery) and T3 (2-year post-surgery). Amount of MS was recorded from case sheets of patients. Mean tongue length reduced, whereas mean tongue height increased at T2 compared to T1 (P value = 0.001 for both). Linear, area and volumetric airway parameters at T2 were significantly reduced (P value = 0.001). All parameters showed statistically nonsignificant increase from T2 to T3 (P value > 0.05). Correlation analysis showed that change in tongue length at T3 did not show statistically significant correlation with amount of MS, changes in linear, area and volumetric airway parameters (P value > 0.05). However, the change in tongue height at T3 showed a significant (P value < 0.05) negative correlation (r value = - 0.742) with change in posterior airway space (PAS). CONCLUSIONS: The appraisal of tongue length and height after MS surgery should be an integral part of diagnosis and treatment planning. The retro-positioning of tongue and increase in its height after MS surgery may compromise pharyngeal airway especially PAS. Additional options such as bi-jaw surgery, debulking of tongue volume and genioplasty should be explored to minimize adverse effects post-surgically.

Evaluation of Airway Dimensions Following Mandibular Setback with Surgery-First Orthognathic Versus Conventional Orthognathic Approach.

BACKGROUND: To evaluate changes in airway dimensions following mandibular setback with conventional orthognathic approach (COA) and surgery-first orthognathic approach (SFOA). MATERIALS AND METHODS: Treatment records of 20 patients who underwent mandibular setback with SFOA/COA were divided into two groups (COA and SFOA, ten patients in each group). Acoustic pharyngometry values were obtained at T0 (01 week prior to surgery), T1 (01-month post-surgery) and T2 (01-year post-surgery). Percentage change in mean volume and area was obtained at T1 (T1-T0) to evaluate airway changes and at T2 (T2-T1) to compare relapse of airway changes in both groups. Changes in airway per mm setback at T1 (T1-T0) and T2 (T2-T1) were also obtained in both groups. RESULTS: For both parameters, SFOA showed greater reduction at T1 and greater relapse at T2 as compared to COA. The reduction in airway volume at T1 was 0.56 mm/mm setback in COA compared to 1.06 mm/mm setback in SFOA (P-value > 0.05). The relapse in airway volume at T2 was 0.15 mm/mm setback in COA compared to 0.25 mm/mm setback in SFOA (P-value > 0.05). The reduction in area at T1 was 0.062 mm/mm setback in COA compared to 0.110 mm/mm setback in SFOA (P-value > 0.05). The relapse in area at T2 was 0.016 mm/mm setback in COA compared to 0.034/mm setback in SFOA (P-value < 0.05). CONCLUSION: In setback cases, SFOA has greater airway reduction immediate post-surgically and greater relapse at 01-year follow-up. Predicting these changes at diagnostic and treatment planning stage may prevent potential adverse events on airway.

Predictability of pharyngeal airway space dimension changes after orthognathic surgery in class II patients: A mathematical approach.

INTRODUCTION: Angle Class II malocclusion due to mandibular retrognathia is a common dentofacial deformity. It is well known that mandibular advancement increases pharyngeal airway dimensions. The aim of this study was to evolve a mathematical method for predicting posterior pharyngeal airway space (PAS) changes based on 2D lateral cephalographic radiographs (LCRs) and expected extent of mandibular advancement prior to BSSO. MATERIALS AND METHODS: Linear regression analyses were performed in order to investigate the relation between the posterior airway space and mandibular advancement. LCRs where carried out to assess skeletal landmarks and pharyngeal airway space pre- (T0) and postoperatively (T1). To detect changes postoperatively, the posterior airway space was divided into three units: nasopharyngeal airway space (superior airway space - SPAS), oropharyngeal airway space (mid airway space - MAS) and hypopharyngeal airway space (inferior airway space - IAS). The differences between the distances of distinct measurement points (DIFF) were measured pre- and postoperatively. DOA referred to the distance of mandibular advancement and DP to the distance between the measurement points preoperatively. The parameters a, b1 and b2 were the regression coefficients that were determined separately for each unit (SPAS, MAS, and IAS). RESULTS: 49 patients (16 male and 33 female) with a mean age of 27.2 years (SD: 10.09), ranging from 18 to 51 years, who underwent mandibular advancement surgery (BSSO) were enrolled in this study. The mean distance of mandibular advancement was 5.05 mm (SD: 1.63). Regarding SPAS and IAS, mandibular advancement did not affect dimensions significantly: SPAS DIFF, 0.33 mm ± 1.13 mm (b1, p = 0.0881; b2, p = 0.087); IAS DIFF, 0.66 mm ± 2.45 mm (b1, p = 0.342; b2, p = 0.765). DOA and DP did not influence DIFF significantly in both sections. Regarding MAS, the mean effect of mandibular advancement was an expansion of 2.47 mm ± 2.24. The linear regression model showed a statistically significant (b1, p = 0.0064; b2, p = 0.0240) influence of DOA and DP on DIFF in posterior airway dimensions pre- and postoperatively. DISCUSSION: Based on preoperative LCR imaging data, a linear regression model was developed as a mathematical approach to allow prediction of PAS development in patients with Angle Class II malocclusions of different degrees. Increasing mandibular advancement was shown to be linked to increasing PAS, while a greater distance between the measuring points preoperatively led to smaller predicted PAS increases postoperatively. CONCLUSION: Predicting pharyngeal airway space (PAS) development after mandibular advancement by analysing lateral cephalometric radiographs (LCR) may be useful in the screening and treatment of obstructive sleep apnea syndrome (OSAS) patients. Our mathematical approach is a simple and sustainable prediction tool based on LTR data for patients with Class II malocclusions.

The Interaction Between Craniofacial Computed Tomographic Dimensional Parameters and BMI in Obstructive Sleep Apnea.

INTRODUCTION: The impact of the dimensional parameters of the pharyngeal bony frame by its length, width and the position of the hyoid upon the severity of obstructive sleep apnea syndrome (OSAS) has not been investigated in depth. Interactions of those parameters with body mass index (BMI) and their overall reciprocal effect on OSAS severity have also not been established. MATERIALS AND METHODS: This retrospective cross-sectional study was conducted on 108 male OSAS patients followed in OSAS outpatient clinics between November 2014 and October 2015. They all underwent a polysomnography test, and an apnea-hypopnea index (AHI) was calculated. They also underwent an upper airway computerized tomographic scan in which three craniofacial parameters were evaluated: inter-pterygoid distance (IPD), hard palate-to-hyoid (HP-H) distance, and gnathion plane-to-hyoid (GP-H) distance. RESULTS: A longer pharynx and an inferiorly placed hyoid bone correlated with the AHI (r = 0.33, p = 0.001 and r = 0.226, p = 0.03, respectively). GP-H correlated with body mass index (BMI) (r = 0.3243, p < 0.001), while HP-H and IPD did not. We found an interaction between BMI and HP-H, but none between GP-H and BMI. IPD did not correlate with OSAS severity, but it correlates with the age of the OSAS patients (r = 0.235, p = 0.015). CONCLUSION: Pharynx length and hyoid position have significant effects upon OSAS severity, and they interact differently with BMI in terms of those effects. Hard palate width increases with age but has no correlation with OSAS severity.

Gender-related difference in the upper airway dimensions and hyoid bone position in Chinese Han children and adolescents aged 6-18 years using cone beam computed tomography.

OBJECTIVE: To investigate the gender-related differences in upper airway dimensions and hyoid bone position in Chinese Han children and adolescents (6-18 years) using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT-scans of 119 boys and 135 girls were selected and divided into four groups (group 1: 6-9 years; group 2: 10-12 years; group 3: 13-15 years; group 4: 16-18 years). The airway dimensions including the cross-sectional area (CSA), anteroposterior (AP) and lateral (LAT) width, length (L), mean CSA and volume (VOL) of upper airway segmentations and hyoid bone position including 11 linear and three angular measurements were investigated using Materialism's interactive medical image control system (MIMICS) 16.01 software. Gender-related differences were analyzed by two independent sample t-tests. RESULTS: No gender-related difference was found in values of the facial morphology, airway dimensions and hyoid bone position for group 1 (p > 0.05). The children and adolescents in groups 2, 3 and 4 showed significant gender-related differences in the measurement results of facial morphology, airway dimensions and hyoid bone positions (p < 0.05). What's more, the measurement values of boys were obviously larger than those of girls except some measurements in group 2. CONCLUSIONS: The measurements of airway dimensions and hyoid bone positions have gender-related differences in children and adolescents aged 10-18 years. These results could be taken into consideration during orthodontic diagnosis and treatment.