Reproducibility of airway dimensions and tongue and hyoid positions on lateral cephalograms

Cephalometry as an aid in the diagnosis of pediatric obstructive sleep apnoea: A systematic review and meta-analysis

Background

Obstructive sleep apnoea (OSA) is part of a spectrum of sleep disorders causing snoring, gasping, and choking while sleeping. In children, OSA can also lead to behavioural issues, hyperactivity, and poor academic performance. Thus, early identification and management of OSA in children is crucial in preventing long-term health problems. The gold standard test for diagnosis is an overnight in-lab polysomnography (PSG). However, due to certain constraints associated with PSG, such as lack of accessibility, high expenses incurred, as well as the need for hospitalization, alternative diagnostic tools are needed. Cephalometry is a non-invasive, affordable diagnostic tool that may offer useful information in the evaluation of OSA. The present systematic review and meta-analysis aimed to evaluate the various cephalometric parameters associated with the diagnosis of OSA in children.

Methods

A structured literature search was performed using the search engines PubMed, Scopus, Web of Science, Cochrane, and Google scholar from inception till July 2022. The weighted mean difference (z-test) was calculated using a random effects method (REM).

Results

16 studies were included in the review and meta-analysis was executed for each cephalometric parameter. The parameters of significance (p < 0.05) in Pediatric OSA with lower heterogeneity were associated with McNamara's and Linder-Aronson's analysis, the hyoid bone position, a retrognathic mandible, and an acute cranial base angle.

Conclusions

Certain parameters in craniofacial morphology may be reliable diagnostic parameters. Further long-term studies are needed in order to shed more light in this area.

The effect of different functional appliances on the sagittal pharyngeal airway dimension in skeletal class II: a retrospective study

The aim of this study was to compare the changes in the sagittal pharyngeal airway dimension (SPAD) in adolescents with Class II mandibular retrusion treated with Invisalign Mandibular Advancement (IMA), prefabricated Myobrace (MB), and Twin block (TB). For this retrospective study, the pre-treatment and post-treatment lateral cephalograms of 60 patients who underwent myofunctional treatment, using either one of the tested appliances were gathered from the files of treated patients. Changes in the SPAD were measured in each group, and comparisons were carried out between the three study groups. Additionally, sagittal skeletal measurements were carried out. Comparisons of the study variables at T0 and T1 between the three groups were performed using one-way ANOVA, while comparisons of the difference (T1-T0) were performed using Kruskal Wallis test. A significant SPAD increase has been reported using the three tested appliances (p < 0.05), with the least change documented with MB use (p < 0.05). Significant antero-posterior improvements have been found with IMA, MB, and TB with an increase in the SNB°, and a decrease in ANB° and Wits appraisal (p < 0.05). Non-significant FMA° changes have been observed post-treatment in the three test groups (p > 0.05). The IMA, MB, and TB generated significant SPAD and sagittal changes, with both IMA and TB surpassing MB in the airway area improvement post-treatment. Moreover, the three tested Class II functional appliances did not affect the vertical dimension.

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.

Cephalometric evaluation of pharyngeal airway and tongue space following treatment with Herbst and AdvanSync appliances : A prospective randomized clinical trial

OBJECTIVES

To evaluate and compare pharyngeal airway and tongue space changes after treatment with fixed functional appliances-Herbst and AdvanSync™ (Ormco, Orange, CA, USA) appliances-in skeletal class II patients in pre- and posttreatment lateral cephalograms.

METHODS

For this randomized, controlled trial, 40 patients (21 male, 19 female) were divided into two groups-a Herbst group (mean age 12.6 ± 0.67 years) and an AdvanSync group (mean age 12.8 ± 0.66 years). Pre- and posttreatment (appliance therapy duration-8 months) lateral cephalograms were traced using a software program to evaluate pharyngeal airway and tongue space changes.

RESULTS

Nasopharyngeal airway, velopharyngeal airway, glossopharyngeal airway, and hypopharyngeal airway increased in the Herbst group by 2.12 mm (p ≤ 0.001), 2.33 mm (p ≤ 0.001), 2.40 mm (p ≤ 0.01), and 1.57 mm (p ≤ 0.05), while in the AdvanSync group the increases were 1.89 mm (p ≤ 0.001), 1.21 mm (p ≤ 0.001), 1.18 mm (p ≤ 0.001), and 1.53 mm (p ≤ 0.001), respectively. In the Herbst group, tongue length and height increases were 2.04 mm (p ≤ 0.01) and 3.74 mm (p ≤ 0.001), while the values in the AdvanSync group were 2.41 mm (p ≤ 0.05) and 2.69 mm (p ≤ 0.001). The change of the tongue tip from the lower occlusal plane was 0.69 mm (p ≤ 0.001) in the Herbst group and 0.77 mm (p ≤ 0.001) in the AdvanSync group. The velopharyngeal airway dimension was correlated positively with that of the retroglossal oropharyngeal airway, which in-turn positively correlated with the laryngopharyngeal airway which correlated well with the distance of the tongue tip from the lower occlusal plane.

CONCLUSIONS

The airway dimensions and tongue parameters increased significantly in both treatment groups in the present study. These changes were higher in the Herbst appliance than in the AdvanSync group, except for the distance of the tongue tip from the lower occlusal plane. A significant difference between the pharyngeal airways was found only for the retropalatal oropharyngeal airway.

Three-dimensional computed tomography analysis of airway volume in growing class II patients treated with Frankel II appliance

OBJECTIVE

The purpose of this retrospective study was to assess the airway volume changes associated with the use of Frankel appliance (FR II) in Class II malocclusion patients using three-dimensional cone beam computed tomography (3D CBCT) imaging.

MATERIALS AND METHODS

The sample consisted of 31 Class II malocclusion patients (mean age 9.24 ± 1.93 years old, 17 males (54.8%) and 14 females (45.2%)) treated with FR II appliance by the same orthodontist for an average of 9 months ± 20 days. CBCT images were taken before and after treatment and upper airway volume changes were measured using Dolphin 3D software version11.0 (Dolphin Imaging, Chatsworth, CA) and statistically compared.

RESULTS

Airway volume of nasal cavity, nasopharynx, oropharynx, hypopharynx and the total airway volume significantly increased after the use of FR II appliance. In addition, significant increase was reported in maxillary base, inter-molar, inter-premolar and inter-canine width. Significant increase in soft tissue thickness was only recorded opposite to CV2.

CONCLUSION

The use of the FR II appliance in growing subjects with Class II malocclusion led to a significant increase in the upper airway volume in addition to the anticipated dental and skeletal transverse expansion effects.

Cephalometric changes in pharyngeal airway dimensions after functional treatment with twin block versus myobrace appliances in developing skeletal class II patients: a randomized clinical trial

BACKGROUND

Several appliances have been used for correction of developing skeletal Class II, including different myofunctional appliances as Twin block (TB)as well as the new pre-fabricated Myobrace (MB) appliance. However, the effects of these devices on the pharyngeal airways have not been compared in the literature. Thus, the aim of this study was to compare the effects of two Class II correction appliances; TB and MB on the sagittal pharyngeal airway dimension (SPAD), including the nasopharyngeal airway area (NPAA), the oropharyngeal airway area (OPAA), and the laryngopharyngeal airway area (LPAA).

METHODS

This is a two parallel arms randomized comparative clinical trial. Twenty-six children of 9-12 years with Skeletal Class II malocclusion due to mandibular deficiency and normal maxillary growth as confirmed by lateral cephalometric X-ray readings (ANB angle > 4° and SNB angle < 78) and Cervical vertebral maturational index (CVMI) 1 or 2 were randomly assigned into two equal groups. Group I: TB, Group II: MB (prefabricated functional appliance, Myofunctional Research Co., Australia). Lateral cephalograms were taken for all patients in both groups before treatment (T1) and after treatment (6 months later) (T2). The primary aim was to assess pre and post treatment changes in the SPAD in each group, and compare between the two study groups. The secondary aim was to evaluate the sagittal skeletal measurements such as the SNA, SNB, ANB, Wits appraisal, as well as vertical skeletal measurements represented by the Frankfurt-mandibular plane angle (FMA) measured pre- and post-treatment. The independent samples t-test was used to compare the two study groups, and the mean difference and 95% confidence intervals (CI) were computed. The paired samples t-test was used to compare various parameters between T1 and T2 within each group. The cutoff for significance was p-value < 0.05. Data were analyzed using IBM SPSS for Windows (Version 26.0).

RESULTS

By Comparing changes in airway measurements within each group, it was found that NPAA, OPAA, and LPAA increased significantly after treatment within each group of MB and TB. TB group showed significantly higher mean difference (T2-T1) in both NPAA and OPAA than MB group with 28.39 (± 56.75) and 40.46 (± 52.16) respectively. The increase in LPAA values was not statistically significant at (T2-T1) between both groups. Regarding skeletal changes, there was a significant increase in the SNB values between T1 and T2 within each group with 2.82 (± 3.32) for MB group and 3.79 (± 3.06) for TB group Moreover, there was a significant decrease in the ANB values between T1 and T2 within each group by 2.42 (± 2.70) for MB group and 3.06 (± 1.14) for TB group. Similarly, there was a significant decrease in the ANB values between T1 and T2 within each group by -2.13 (± 0.62) for MB group and - 2.46 (± 0.72) for TB group. No significant differences were found between both groups in SNA, SNB, ANB and Wits appraisal at p = 0.06, p = 0.45, p = 0.43 and p = 0.22 respectively. FMA did not show significant difference between T1 and T2 within each group, nor showed a significant mean difference between both groups at T2-T1.

CONCLUSIONS

TB was more effective than MB in improving the upper (NPAA) and middle (OPAA) airways, while no difference was found regarding the lower airway (LPAA). Both TB and MB reduced the severity of developing skeletal class II due to mandibular retrognathism by forward posturing of the mandible. Thus, patients with airway problems would benefit more from TB than MB.

Effects of Elastodontic Appliance on the Pharyngeal Airway Space in Class II Malocclusion

BACKGROUND

The present study analyzed the changes obtained on the upper airway and hyoid bone dimensions in a group of patients with skeletal Class II malocclusion treated with functional elastodontic devices compared to an untreated control group.

METHODS

A group of 33 patients (19 females and 14 males) with Class II malocclusion treated with AMCOP^® SC elastodontic device was compared with a control group of 35 subjects (17 females and 18 males) with untreated Class II malocclusion. Lateral cephalograms were available at the start (T0) and end of treatment/period of observation (T1). Cephalometric analysis was performed and linear measurements to evaluate airway space and hyoid bone position were also obtained. A multivariate analysis of variance for repeated measures (MANOVA) was performed to determine the effects of interactions for the groups for time.

RESULTS

Statistically significant differences were found in the study group from T0 and T1 with an improvement of superior upper airway (SPAS p < 0.0001), while in the control group it did not change in a statistically significant way from T0 to T1. The MANOVA test showed statistically significant differences between the two groups for the changes of SPAS (p = 0.003), IAS (p = 0.049), and H-C3 vertical (p = 0.038) values.

CONCLUSIONS

Functional elastodontic therapy produced significant favorable airway changes in skeletal class II subjects.

Correlation of Palatal Index With Pharyngeal Airway in Various Skeletal Patterns

Introduction This retrospective study aimed to correlate palatal index with pharyngeal airway in class I, class II and class III skeletal patterns. Materials and methods A total of 30 individuals with a mean age of 17.5 years were included in the study. The subjects were categorized on the basis of ANB (A point, nasion, B point) angle into skeletal class I, II, and III patterns (N=10). Using Korkhaus analysis, palatal height, palatal breadth, and palatal height index were calculated from the study models. From the lateral cephalogram, the dimensions of the upper and lower pharyngeal airways were measured using McNamara Airway Analysis. The results were calculated using the ANOVA test. Results A statistically significant difference was found in all three groups of class I, II, and III malocclusions for palatal index and airway dimensions. The skeletal class II malocclusion participants exhibited the highest mean values for the palatal index (P=0.03). Class I had the highest mean value for the upper airway (P=0.041), whereas class III had the highest mean value for the lower airway (P=0.026). Conclusion It was concluded that subjects with the class II skeletal pattern have a high palate and reduced upper and lower airways when compared with class I and class III skeletal patterns, which showed larger upper and lower airways, respectively.

Vowel sound production and its association with cephalometric characteristics in skeletal Class III subjects

BACKGROUND

This study aimed to evaluate differences in vowel production using acoustic analysis in skeletal Class III and Class I Japanese participants and to identify the correlation between vowel sounds and cephalometric variables in skeletal Class III subjects.

MATERIALS AND METHODS

Japanese males with skeletal Class III (ANB < 0°) and Class I skeletal anatomy (0.62° < ANB < 5.94°) were recruited (n = 18/group). Acoustic analysis of vowel sounds and cephalometric analysis of lateral cephalograms were performed. For sound analysis, an isolated Japanese vowel (/a/,/i/,/u/,/e/,/o/) pattern was recorded. Praat software was used to extract acoustic parameters such as fundamental frequency (F0) and the first four formants (F1, F2, F3, and F4). The formant graph area was calculated. Cephalometric values were obtained using ImageJ. Correlations between acoustic and cephalometric variables in skeletal Class III subjects were then investigated.

RESULTS

Skeletal Class III subjects exhibited significantly higher/o/F2 and lower/o/F4 values. Mandibular length, SNB, and overjet of Class III subjects were moderately negatively correlated with acoustic variables.

LIMITATIONS

This study did not take into account vertical skeletal patterns and tissue movements during sound production.

CONCLUSION

Skeletal Class III males produced different /o/ (back and rounded vowel), possibly owing to their anatomical positions or adaptive changes. Vowel production was moderately associated with cephalometric characteristics of Class III subjects. Thus, changes in speech after orthognathic surgery may be expected. A multidisciplinary team approach that included the input of a speech pathologist would be useful.

Changes in hyoid bone and tongue position in Class I subjects after orthodontic treatment with rapid palatal expander

OBJECTIVE

To evaluate the effects of the rapid palatal expander (RPE) on the hyoid bone and tongue position in skeletal Class I patients, compared to control groups.

METHODS

Eighty-four Class I subjects, aged 6-14, were selected. Among these, 28 patients were treated with RPE, 28 with function-generating bite (FGB) appliance, and 28 were untreated. Lateral cephalograms taken before (T0) and after (T1) treatment were retrieved. Changes in the hyoid bone and tongue position were evaluated, and the area above the tongue was measured.

RESULTS

No significant difference in the hyoid and tongue posture was observed across the groups. However, there were significant differences for HC3 (distance from H-point to the third cervical vertebrae), H2H (distance from H-point to SN plane), and TT-Eb (tongue length) between T0 and T1 in all groups.

CONCLUSION

The results suggest that hyoid bone and tongue position changes were related to growth rather than treatment.

Evaluation of effects of removable functional orthodontic apparatus on the upper airway size by cephalometric films

OBJECTIVE

Respiration is a vital functional process that has effects on normal craniofacial development. Since the upper airway formations and dentofacial structures are adjacent to each other, the interaction between them is possible. The aim of this study is to evaluate the effects of removable functional appliances used in the treatment of patients with mandibular and maxillary growth retardation-stenosis in Class I, Class II, and Class III malocclusion on the upper airway.

MATERIALS AND METHODS

Thirty two patients were studied in the study. The patients were divided into 4 groups according to treatment modalities. Maxillary expansion device group (Group A), Twinblock-Monoblock group (Group B), Face mask group (Group C), and Chincup group (Group D). The upper airway size in the lateral cephalometric images of the patients before orthodontic treatment with removable functional appliances (T0) and the upper airway size in the lateral cephalometric images taken after the end of the orthodontic treatment with the removable functional appliances (T1) were retrospectively compared.

RESULT

Most upper airway size increased after orthodontic treatment (T1) in the individuals who received orthodontic treatment with A, B, C, and D type removable functional appliances compared to pre-treatment (T0). When the changes in upper airway size pre-treatment (T0) and post-treatment (T1) were compared, the change in upper airway size according to treatment groups was found to be statistically different (p <0.05).

CONCLUSION

Since a large part of the upper airway is located in the craniofacial complex, orthodontists also examine the airway for diagnosis and planning and can regulate the airway in case of occlusion that has occurred or may occur. This puts orthodontists in an important place to intervene when complications occur or may develop in the upper airway. By determining the effects of removable functional appliances on the airways, airway problems that may be experienced at an early age can be prevented.

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.

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.

Airways cephalometric norms from a sample of Caucasian Children

Background

The diagnosis of the respiratory pattern and the analysis of airway dimension using lateral cephalometric radiographs include the study of the adenoid region, free air space of the nasopharynx and oropharynx, soft palate and posterior part of the tongue. The objective of this study is to identify the airways cephalometric norms from a sample of Caucasian children, in relation to gender, age and type of malocclusion.

Material and Methods

A total of 480 patients of both sexes were included in the study, the age ranged between 6-12 years. The radiographic records were analyzed using the Nemoceph® 11.3.0 software and the diagnosis of skeletal class was performed using the Steiner analysis. The cephalometric measurements used for the study were PNS-AD1, AD1-Ba, PNS-Ba, Ptm-Ba, PNS-H and the upper and lower airways according to McNamara analysis. The comparative analysis was performed using only upper and lower airways variables.

Results

The mean values for each variable in the total sample were 23.2 mm (PNS-Ad1), 24.7 mm (Ad1-Ba), 47.6 mm (PNS-Ba), 45.7 mm (Ptm-Ba), 30.0 mm (PNS-H), 9.3 mm (upper airway) and 11.5 mm (lower airway). According to gender, all variables were greater in the boys group except for the lower airway. In relation to age, the mean values increased with age except for the lower airway and the AD1-Ba variables. In patients with skeletal Class I greater dimensions of the upper and lower airways were observed.

Conclusions

In this Caucasian sample, it has been observed a tendency of minor airway dimensions in patients with skeletal Class II, lower age range female gender. It has been observed only significant differences between age and skeletal class for lower airways variable and, in relation to upper airways variable the results were significant in relation to age.

Key words:Child development, Diagnostic XRay, Cephalometry, Respiratory system diagnostic imaging.

Quantifying Upper Airway Changes Following Mandibular Orthognathic Surgery

ABSTRACT

The aim of this study was to quantify upper airway changes following mandibular orthognathic surgery. Treatment records of 50 patients who underwent mandibular orthognathic surgery were divided into 2 groups, that is, Group 1: Cases treated with Mandibular Advancement Surgery and Group 2: Cases treated with Mandibular Setback Surgery with 25 patients in each group. The Lateral Cephalogram and Acoustic Pharyngometry records of both groups were studied at T0 (01 week before surgery) and T1 (01 year postsurgery) for changes in linear airway measurements (Nasopharyngeal Airway Space - NAS, Superior Airway Space - SAS, Posterior Airway Space - PAS and Hypopharyngeal Airway Space (HAS)), hyoid bone position (Mandibular Plane Hyoid distance), mean area and mean volume. The percentage change and change in these parameters per millimeter advancement or setback of mandible at T1 was calculated. A significant increase in linear airway parameters (SAS and PAS); decrease in hyoid distance; and increase in volume and area of upper airway was observed at T1 in Group 1 and reverse was observed in Group 2. The change in airway parameters (SAS, PAS, mean volume and area) was more significant in Group 1 as compared to Group 2. In the current airway centric approach, meticulous assessment and prediction of long-term airway changes post surgery should be an integral part of ortho-surgical diagnosis and treatment planning and suitable modifications in the treatment plan must be made to cater for any potential adverse effects on airway.

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.

Changes in the upper airway, hyoid bone and craniofacial morphology between patients treated with headgear activator and Herbst appliance: A retrospective study on lateral cephalometry

Background

The present study compared the treatment changes in the upper airway, hyoid bone position and craniofacial morphology between two groups of children with skeletal class II malocclusion treated with the headgear activator (HGA) and Herbst appliance (Herbst).

Setting and sample population

Orthodontic population from the Faculty of Dentistry of the University of Hong Kong.

Methods

Thirty‐four skeletal class II patients treated with the HGA (17 patients, mean age 10.6 ± 1.5 years) and the Herbst (17 patients, mean age 11.0 ± 1.4 years) were matched for sex, age, overjet, skeletal class and mandibular divergence. The patients received lateral cephalometric radiographs (LCRs) at the beginning of treatment (T₁), after treatment (T₂) and at follow‐up (T₃). In the HGA group, patients underwent LCRs 7 months before the beginning of treatment (T₀), which were used as growth reference for intra‐group comparison. Paired Student's t tests were used for intra‐ and inter‐group comparisons (α = .05).

Results

Treatment changes (T₂‐T₁) did not differ significantly between the groups. However, at follow‐up (T₃‐T₁) the Herbst group showed a smaller increase than the HGA group in the vertical position of the hyoid bone relative to the Frankfort plane (P = .013) and mandibular plane (P = .013).

Conclusions

There were no significant differences in the upper airway, hyoid bone position and craniofacial morphology between the groups at the end of treatment. However, the Herbst may provide better long‐term control of the vertical position of the hyoid bone than the HGA in children with skeletal class II malocclusion.

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

Introduction

The spatial position and dimensions of oral and pharyngeal soft tissues change post-mandibular advancement (MA) surgery which involves changes in position of soft palate, tongue and associated musculature. There is no study which simultaneously evaluates changes in tongue length and height post-MA surgery and correlates these changes with changes in upper airway dimensions and the amount of MA.

Materials and Methods

Treatment records of 18 patients that underwent MA with bilateral sagittal split ramus osteotomy were evaluated at T1 (01 week before surgery) and T2 (06 months post-surgery). Linear airway and tongue measurements were done on lateral cephalogram. Mean volume and mean pharyngeal area values were recorded from the acoustic pharyngometry (AP) records of patients.

Results

A statistically significant increase in tongue length (P value < 0.001) and nonsignificant change in tongue height were observed at T2 (P value > 0.05). A statistically significant increase in airway parameters recorded on both lateral cephalogram and AP was observed at T2 (P value < 0.001). Correlation analysis did not show a statistically significant correlation of change in tongue length and tongue height at T2 with the amount of MA, change in airway parameters on lateral cephalogram and AP (P value > 0.05).

Conclusions

Mandibular advancement surgery is a viable option for improvement in pharyngeal airway in skeletal Class II patients with retrognathic mandible. Changes in tongue length observed in our study may correspond to the stretch of protruders of tongue, especially genioglossus, and may point toward possible relapse on a long-term follow-up.

Evaluation of Changes in the Pharyngeal Airway Space as a Sequele to Mandibular Advancement Surgery: A Cephalometric Study

PURPOSE

To evaluate effect of mandibular advancement on pharyngeal airway space using lateral cephalogram.

MATERIALS AND METHODS

Twenty patients who were diagnosed with class II skeletal malocclusion and underwent surgical intervention for the correction of their dentofacial deformity following orthodontic treatment were included. The soft tissue changes in the pharyngeal space were brought about by the surgical intervention, and the changes that had occurred in increasing the airway were evaluated by using cephalogram.

RESULTS

The results of this study showed that following mandibular advancement surgery, the pharyngeal airway space increased along with an increase in the length and thickness of the uvula with a reduction in the angulation. All the changes remained stable in the late postoperative phase.

CONCLUSION

Patients who underwent mandibular advancement showed a significant increase in the pharyngeal airway space and that remained stable during the evaluation period. As a consequence, mandibular advancement seems to be the most stable surgical movement in relation to airway dimensional gains.

Short-term effects of the Sander bite-jumping appliance on the pharyngeal airways in subjects with skeletal Class II malocclusion: A retrospective case-control study

BACKGROUND

Skeletal Class II subjects present often a retruded mandible that might increase the probability of breathing disorders.

OBJECTIVE

To evaluate the effects of functional treatment by means of the Sander bite-jumping appliance (BJA) on the upper airways of growing subjects.

METHODS

Thirty-four subjects (21 males, 13 females; mean age 11.1 ± 1.2 years) with skeletal Class II malocclusion due to mandibular retrusion were treated with the Sander BJA (BJA group). The control group consisted of thirty-four untreated subjects with skeletal Class II malocclusion (25 males, 9 females; 10.4 ± 1.2 years; CTR group). The effect of the Sander BJA appliance on the airway dimensions was evaluated by comparing lateral cephalograms recorded before (T0) and after (T1) the period of observation/treatment. Within- and between-group comparisons were statistically evaluated according to the distribution of the data (P < .05).

RESULTS

The oropharyngeal region (ph_pph) increased in the BJA group (1.8 ± 3.2; P = .001) but the difference respect to the CTR group was not statistically significant (0.73 ± 4.0; P = .314; P = .077). The tongue height (th) increased in the BJA group (2.8 ± 3.7; P < .001), and this increase was statistically significant respect to the CTR group (0.6 ± 4.7; P = .461; P = .038). In the BJA, the Ans_Pns_P angle showed a statistically significant decrease (-3.8 ± 7.8; P = .007) compared to the CTR group (-0.1 ± 5.4; P = .705; P = .026).

CONCLUSIONS

The airway dimensions increased for both control subjects and Class II patients treated with Sander BJA due to physiological growth. The Sander BJA induced a statistically significant change in the tongue and soft palate position, but the clinically relevant of these changes is questionable.

Airway Analysis in Skeletal Class I and Class II Subjects with Different Growth Patterns: A 2D Cephalometric Study

OBJECTIVE

A two-dimensional cephalometric study was carried out to assess the airway among individuals with Class I and Class II skeletal base.

MATERIALS AND METHODS

Class II subjects were further categorized into horizontal and vertical growers and average growth patterns to check the possible relationship between the facial skeleton and pharyngeal airway. Lateral cephalograms of 150 subjects were obtained using standard protocol in natural head position (NHP). Nasopharyngeal and oropharyngeal linear, and angular and nasopharyngeal area measurements were obtained using standardized tracing technique. Analysis of variance (ANOVA), level of significance, and post hoc Turkey's test were performed to assess the correlation between skeletal pattern of the individual and airway dimension. Gender discrimination was assessed using independent sample t test.

RESULTS

In linear measurements, significant differences were observed among upper pharynx (0.039), adenoid tissue 1 (0.036), and adenoid tissue 2 (0.01). In angular measurements, differences were observed with angle of nasopharynx (0.008). The nasopharyngeal area measurements were also associated with significant difference (0.038) with Class II vertical growers less than those with Class I average and Class II horizontal groups.

CONCLUSION

Class II vertical growers had significantly reduced nasopharyngeal airways.

Changes in pharyngeal airway dimensions following incremental and maximum bite advancement during Herbst-rapid palatal expander appliance therapy in late adolescent and young adult patients: a randomized non-controlled prospective clinical study

OBJECTIVES

This was a parallel, assessor-blinded, randomized, non-controlled prospective trial with the objective to evaluate and compare the effects of maximum advancement (MA) and incremental advancement (IA) of mandible with cast-splint-type Herbst-rapid palatal expander (RPE) appliance on pharyngeal airway dimensions and hyoid bone position in skeletal Class II late adolescents and young adults.

MATERIALS AND METHODS

A total of 48 patients (19 male and 29 female, mean age: 15.45 ± 1.42 years) with skeletal Class II malocclusion were treated with cast-splint Herbst-RPE appliance. Inclusion criteria were skeletal Class II malocclusion, mandibular retrognathia, bilateral Class II molar and canine relationship, increased overjet, normal or decreased vertical dimensions, minimal crowding, and no missing teeth. Enrolled subjects were randomly allocated into two groups according to mandibular advancement type: IA and MA Herbst-RPE therapy. The outcome assessor was blinded. Advancement in MA group was adjusted until tête-à-tête incisor relationship or super Class I molar relationship was obtained. Initial forward movement in IA group was 4-5 mm and followed by bimonthly 2 mm of subsequent advancements. Skeletal, pharyngeal airway, and hyoid measurements were performed using lateral cephalometric films. Statistical significance was set at P value of less than 0.05.

RESULTS

Hypopharyngeal airway dimensions (P < 0.000), oropharyngeal airway dimensions (P < 0.001, P < 0.007), and PASmin values (P < 0.010, P < 0.009) were increased and soft palate angle (P < 0.018, P < 0.007) was decreased in MA and IA groups significantly. Hyoid bone measurements revealed a significant difference in H-Cv2 distance (MA: P < 0.002-P < 0.002; IA: P < 0.001-P < 0.043) and H-Cv3 distance (P < 0.005, P < 0.001) for both groups. However, all these changes did not differ among the MA and IA activation groups. ANB°, Wits, overjet, and overbite measurements decreased and SNB°, Co-Gn, Na-Me, ANS-Me, and S-Go increased with the treatment significantly in both mandibular advancement groups (P < 0.000-P < 0.040).

CONCLUSIONS

Herbst-RPE appliance provided a similar improvement in the oropharyngeal and hypopharyngeal airway dimensions and similar changes in sagittal and vertical hyoid position for both maximum and IA protocols in patients with skeletal Class II malocclusion.

TRIAL REGISTRATION

ISRCTN69743543.

Effects of bicuspid extractions and incisor retraction on upper airway of Asian adults and late adolescents: A systematic review

OBJECTIVES

This systematic review aimed to assess the effects of bicuspid extractions and incisor retraction on airway dimension, hyoid position and breathing of adults and late adolescents.

METHODS

The review was conducted according to PRISMA guidelines. Eight databases including PubMed, EMBASE, Web of Science and Scopus were searched to August 2018. Minimum age of participants was 16 years. The intervention was dual-arch bicuspid extractions with incisor retraction. Outcomes were airway dimension, hyoid position and breathing assessment.

RESULTS

All nine publications meeting inclusion criteria were from Asia. They were divided into three Asian subregions. All East Asian lateral cephalometric studies reported anteroposterior airway narrowing at the oropharynx and sometimes the hypopharynx. However, the narrowing was small, comparable to measurement errors, and highly variable. Two out of three East Asian computed tomography (CT) studies described reductions in airway dimensions. The single functional breathing study showed increased simulated flow resistance after incisor retraction in East Asians. South Asian studies had mixed findings, with some reporting significant airway narrowing. The single study from West Asia found no significant airway or hyoid changes.

CONCLUSIONS

Airway response to bicuspid extractions and incisor retraction varied substantially when assessed with cephalometry. CT measurements present larger effect sizes and smaller variations, providing stronger evidence of airway narrowing. Orthodontic extractions for incisor retraction may be more frequently indicated in Asia, and East Asians seem particularly susceptible to airway narrowing and postero-inferior hyoid movement with incisor retraction. Better designed CT studies are needed for confirmation due to small effect size and large variability.

Reliability of lateral cephalometric radiographs in the assessment of the upper airway in children: A retrospective study

OBJECTIVES

To test the reliability of Lateral cephalometric radiographs (LCRs) for use in the assessment of the upper airway, hyoid bone, soft palate, and tongue.

MATERIALS AND METHODS

The records of 57 healthy Chinese children from a nonhospital population (mean age = 12.6 years, SD = 0.5, 28 males and 29 females) who received two consecutive LCRs in the natural head posture were retrospectively analyzed. Fifteen linear, angular, and area measurements were used to describe the airway, hyoid bone, soft palate, and tongue. The reliability between the two LCRs was assessed with the intraclass correlation coefficient (ICC) and F-test. Errors were estimated with the Dahlberg and Bland-Altman method, and intra- and inter-assessor agreements were determined.

RESULTS

Measurements of upper airway and hyoid bone had excellent method reliability, intra-assessor reliability, and inter-assessor reliability (ICC > 0.8). However, the method reliability and the inter-assessor reliability for soft palate and tongue was less favorable (ICC from 0.60 to 0.96). Soft palate area and thickness were the most critical parameters. Intra-assessor reliability was greater than both method reliability and inter-assessor reliability (which were similar).

CONCLUSIONS

The measurement of upper airway morphology, defined as the intramural space, and of the hyoid bone position were highly reliable on LCRs of children. However, the limited reliability in the assessment of tongue and soft palate area may compromise the diagnostic application of LCRs to these structures.

Evaluation of Airway Measurements in Class II Patients Following Functional Treatment

Objective

This study aimed to evaluate the effect of fixed and removable functional treatment on pharyngeal airway measurements in class II patients.

Methods

In this study, patients treated with fixed (Forsus Fatigue Resistant Device-FRD) and removable (twin-block-TWB) appliances were included (n=15, eight females, seven males in each group). These groups were compared with untreated individuals as the control group (n=10). The mean age of individuals was 13.22±2.39 years. Initial and post-treatment cephalometric radiographs were digitized, and the sagittal pharyngeal airway changes were evaluated. The pharyngeal airway was divided into the nasopharynx, oropharynx, and hypopharynx. The one-way ANOVA, Kruskal-Wallis test, and paired samples t-test were used for statistical analyses.

Results

At the initial values, no statistically significant difference was observed between the groups. Only the ANB values differed between the groups (p<0.05). Although the skeletal effects of removable and fixed treatment were not exactly the same, the changes of the airway dimensions were similar.

Conclusion

The TWB and FRD appliances lead to an increase in nasopharynx, oropharynx, and hypopharynx sagittal dimensions. However, in terms of the effect on airway sagittal dimensions, there was no significant difference between treatment groups and the control group.

Long-term effects of Class II Herbst treatment on the pharyngeal airway width

Objective

The aim was to assess the long-term effects of Class II malocclusion treatment with the Herbst appliance on the pharyngeal airway (PA) width in comparison to untreated individuals with Classes I and II malocclusion.

Methods

Lateral cephalometric radiographs of 13 male Class II patients from before (T1) and after (T2) treatment with the Herbst appliance as well as after the end of growth (T3) were retrospectively analyzed and compared to two untreated age- and gender-matched samples with Class I (n = 13) or Class II (n = 13) malocclusion. The PA dimensions were measured using the parameters p (narrowest distance between the soft palate and the posterior pharyngeal wall) and t (narrowest distance between the base of the tongue and the posterior pharyngeal wall). In addition, standard cephalometric measurements were performed.

Results

Relevant changes in PA dimensions were only seen for the post-treatment period, during which the distances p and t showed a significant increase in the Herbst group only (∆p: 2.3 mm, ∆t: 3.3 mm) while remaining similar in both untreated groups (∆p: 0.5 mm, ∆t: 0.5 mm, respectively, ∆p: 0.7 mm, ∆t: 1.6 mm). During the same period, posterior face height showed a significantly larger increase in the Herbst group than in both control groups (8.2 versus 5.8 mm, respectively, 5.4 mm), whereas anterior face height (NL-Me) showed a similar development in all groups (4.6 versus 4.4 mm, respectively 3.2 mm).

Conclusion

In the long term, Herbst treatment resulted in a significant post-treatment increase of PA width, possibly due to an increased lower posterior facial height development compared to untreated individuals.

Evaluation of tongue volume and oral cavity capacity using cone-beam computed tomography

The aims of this study were to reveal the usefulness of a newly developed method for measuring tongue volume (TV) and oral cavity capacity (OCC) and to assess the relationship between them. The tongue was coated with a contrast agent, and the TV and OCC were determined using cone-beam computed tomography (CBCT). We enrolled 20 adults who were scheduled to undergo CBCT to evaluate the relationship of the third molar roots to the alveolar nerve before molar extraction. Each participant’s tongue was coated with a contrast agent, and CBCT of the tongue and oral cavity was performed. Using computer software, we evaluated reconstructed 3D images of the TV, oral cavity proper volume (OCPV), and OCC. The mean TV was 47.07 ± 7.08 cm³. The mean OCPV and OCC were 4.40 ± 2.78 cm³ and 51.47 ± 6.46 cm³, respectively. There was a significant correlation between TV and OCC (r = 0.920; p < 0.01) but not between TV and OCPV. The mean TV/OCC ratio was 91 ± 5%. The proposed method produced CBCT images that enabled effective measurement of TV and OCC. This simple method of measuring TV and OCC will be useful in the diagnosis on the tongues with abnormal size.

Evaluations of the tongue and hyoid bone positions and pharyngeal airway dimensions after maxillary protraction treatment

OBJECTIVE

To assess changes in the tongue and hyoid bone positions and airway dimensions after maxillary protraction using lateral cephalograms.

METHODS

Lateral cephalograms were obtained before (C0) and after (C1) an observation period for untreated children with skeletal Class I malocclusion and before (T0), immediately after (T1), and one year after (T2) maxillary protraction in children with skeletal Class III malocclusion. Cephalometric measurements were compared between the time points in both patient groups.

RESULTS

Immediately after maxillary protraction, the tongue moved superiorly and the nasopharyngeal and superior oropharyngeal airway dimensions increased. No significant changes in the middle or inferior oropharyngeal airway dimensions or in the hyoid bone position were noted after treatment.

CONCLUSIONS

Maxillary protraction improved tongue posture and modified the nasopharyngeal and superior oropharyngeal airway dimensions in patients with skeletal Class III malocclusion. Consequently, maxillary protraction may restore the intra- and extraoral balance and improve respiratory function.

Effects of bodily retraction of mandibular incisors versus mandibular setback surgery on pharyngeal airway space: A comparative study

OBJECTIVE

The purpose of this study was to compare the changes induced in the pharyngeal airway space by orthodontic treatment with bodily retraction of the mandibular incisors and mandibular setback surgery without extraction.

METHODS

This retrospective study included 63 adult patients (32 men and 31 women). Thirty-three patients who had been treated via four-bicuspid extraction and bodily retraction of the mandibular incisors (incisor retraction, IR group) were compared with 30 patients who had been treated via mandibular setback surgery (MS group) without extraction. Lateral cephalograms were acquired and analyzed before (T1) and after treatment (T2).

RESULTS

The superior pharyngeal airway space did not change significantly in either group during treatment. The middle pharyngeal airway space decreased by 1.15 ± 1.17 mm and 1.25 ± 1.35 mm after treatment in the IR and MS groups, respectively, and the decrease was comparable between the two groups. In the MS group, the inferior pharyngeal airway space (E-IPW) decreased by 0.88 ± 1.67 mm after treatment (p < 0.01). The E-IPW was larger in the MS group than in IR group at T1, but it did not differ significantly between the two groups at T2. No significant correlation was observed between changes in the pharyngeal airway space and the skeletal and dental variables in each group.

CONCLUSIONS

The middle pharyngeal airway space decreased because of the posterior displacement of the mandibular incisors and/or the mandibular body. The E-IPW decreased only in the MS group because of the posterior displacement of only the mandibular body.

Tomographic Analysis of the Impact of Mandibular Advancement Surgery on Increased Airway Volume

PURPOSE

This study aimed to quantify, using cone-beam computed tomography (CBCT) in patients who underwent a mandibular advancement surgery associated with genioplasty, three-dimensional changes in airway space and to evaluate whether these changes differ between men and women.

MATERIALS AND METHODS

Preoperative and 8-month postoperative CBCT scans of 38 patients aged 18-45 years of either sex and any ethnicity who underwent mandibular advancement surgery associated with genioplasty were analyzed using the Xoran software (Xoran Technologies, Ann Arbor, MI, USA). The linear distances gonion-gnathion (Go-Gn) and condylion-menton (Co-Me) were obtained. Airway volume was measured using the Dolphin Imaging software, version 11.0. Then, data were tabulated and analyzed using Student's t-test.

RESULTS

Mean patient age was 30.3 years; 39.47% were men and 60.63% were women. The mean Go-Gn distance was 72.05 mm before surgery and 78.56 mm after surgery, with a mean gain of 6.51 mm. The mean Co-Me distance was 113.47 mm before surgery and 119.89 mm after surgery, with a mean increase of 6.42 mm. Both differences were statistically significant. The mean volume of airway space was 17,272.92 mm3 before surgery and 24,173.74 mm3 after surgery, with a statistically significant mean increase of 6900.82 mm3. There was no statistically significant difference in mean volumetric gain between men (7566.69 mm3) and women (7456.69 mm3).

CONCLUSION

Mandibular advancement surgery results in significant increase of airway space, and there is no difference in airway volume between men and women.

Changes in airway dimensions following functional appliances in growing patients with skeletal class II malocclusion: A systematic review and meta-analysis

OBJECTIVES

The purpose of the study was to evaluate the treatment effects of functional appliances (FAs) on upper airway dimensions in growing Class II patients with mandibular retrognathism.

METHODS

Five databases and the references of identified articles were electronically searched for relevant studies that met our eligibility criteria. The quality of the included studies was assessed using the Newcastle-Ottawa Scale. The effects of FAs on airway dimensions were combined by meta-analysis using the RevMan and STATA software.

RESULTS

Seven studies (177 treated patients with mean age: 11.48 years and 153 untreated controls with mean age: 11.20 years) were included in this review. Compared to the control group, the oropharyngeal dimensions in the treatment group subjects were significantly increased at the superior pharyngeal space (MD = 1.73 mm/year, 95% CI, 1.13-2.32 mm, P < 0.00001), middle pharyngeal space (MD = 1.68 mm/year, 95% CI, 1.13-2.23 mm, P < 0.00001) and inferior pharyngeal space (MD = 1.21 mm/year, 95% CI, 0.48-1.95 mm, P = 0.001). No significant differences were found in nasopharyngeal and hypopharyngeal dimensions and the position of hyoid bone (P > 0.05). Soft palate length and soft palate inclination were improved significantly in the treatment group (P < 0.05).

CONCLUSIONS

The results showed that FAs can enlarge the upper airway dimensions, specifically in the oropharyngeal region, in growing subjects with skeletal Class II malocclusion. The early intervention for mandibular retrognathism with FAs may help enlarge the airway dimensions and decrease potential risk of obstructive sleep apnea syndrome for growing patients in the future.

Effect of functional appliances on the airway dimensions in patients with skeletal class II malocclusion: A systematic review

OBJECTIVES

The aim of the present systematic review was to assess the effect of functional appliances on the airway dimensions in patients with skeletal Class II malocclusion.

MATERIALS AND METHODS

Articles were identified through a literature survey carried out through the following databases: (1) PUBMED, (2) Google Scholar, (3) The Cochrane Library, (4) Embase, (5) Lilac, and (6) Web of Scholars. The systematic review analyzed 12 articles comprising removable functional appliances, 3 articles with fixed functional appliances, and 2 articles having both fixed and removable functional appliances.

RESULTS

Qualitative assessment was done for all the 17 studies. The effect of functional appliances in the dimensions of three airway spaces - nasopharynx, oropharynx, and hypopharynx were analyzed.

CONCLUSIONS

Significant increase in the dimensions of nasopharynx and oropharynx was observed with Activator. Significant increase in the nasopharynx and hypopharynx (male patients) was observed with Bionator. Insignificant increase in the oropharynx was observed with the same. Significant increase in the oropharynx and hypopharynx was observed with Twin Block. Insignificant increase in the nasopharynx was observed with the same. Significant increase was observed only in the hypopharynx for Frankel II. Decreased or insignificant change was observed with FMA, MPA IV, and Herbst appliances.

Upper airway changes following single-step or stepwise advancement using the Functional Mandibular Advancer

OBJECTIVES

Purpose of the present study was to determine and compare possible changes in the dimensions of the pharyngeal airway, morphology of the soft palate, and position of the tongue and hyoid bone after single-step or stepwise mandibular advancement using the Functional Mandibular Advancer (FMA).

PATIENTS AND METHODS

The sample included 51 peak-pubertal Class II subjects. In all, 34 patients were allocated to two groups using matched randomization: a single-step mandibular advancement group (SSG) and a stepwise mandibular advancement group (SWG). Both groups were treated with FMA followed by fixed appliance therapy; the remaining 17 subjects who underwent only fixed appliance therapy constituted the control group (CG). The study was conducted using pre- and posttreatment lateral cephalometric radiographs. Data were analyzed by paired t test, one-way analysis of variance, and Pearson's correlation coefficient.

RESULT

In the SWG and SSG, although increases in nasopharyngeal airway dimensions were not significant compared with those in the CG, enlargements in the oropharyngeal airway dimensions at the level of the soft palate tip and behind the tongue, and decreases in soft palate angulation, were significant. Tongue height increased significantly only in the SWG. Compared with the CG, while forward movement of the hyoid was more prominent in SSG and SWG, the change in the vertical movement of the hyoid was not significant. No significant difference between SWG and SSG was observed in pharyngeal airway, soft palate, tongue or hyoid measurements.

CONCLUSIONS

The mode of mandibular advancement in FMA treatment did not significantly affect changes in the pharyngeal airway, soft palate, tongue, and hyoid bone.

How has our interest in the airway changed over 100 years?

Since the beginning of our specialty, our understanding of the link between function and facial growth and development has progressively improved. Today, we know that children with sleep-related breathing problems will often develop distinctive facial characteristics. In adults, sleep apnea can result in serious morbidity and mortality. Orthodontists can ask sleep-related questions in the health history to help identify sleep breathing disorders. Treating these patients presents unique opportunities for orthodontists to collaborate with other medical specialties to improve a patient's health and treatment outcome. Research presented in our Journal in the next century may shed new light that will help us better identify the problem and aid the specialty in developing more effective evidence-based treatment. Additional efforts are needed to understand the physiology, neurology, and genetics of sleep breathing disorders.

Upper and lower pharyngeal airway space in West-Tamil Nadu population

Aim:

To compare the upper and lower pharyngeal airway (LPA) width in Class II malocclusion patients with low, average, and high vertical growth patterns.

Study Design:

Cross-sectional analytical study.

Materials and Methods:

Pretreatment lateral cephalometric films of 90 Class II subjects were used to measure the upper and LPAs. The inclusion criteria were subjects of West-Tamil Nadu, aged between 14 and 25 years, only skeletal Class II subjects of either gender and no pharyngeal pathology at initial visit. The sample comprised a total of 90 Class II subjects divided into three groups according to the vertical facial pattern: Normodivergent (n = 30), hypodivergent (n = 30), and hyperdivergent (n = 30). The assessment of upper and LPAs was done according to McNamara's airway analysis.

Statistical Analysis:

The intergroup comparison of the upper and LPAs was performed with one-way analysis of variance and the Tukey test was used to compare among the various vertical patterns.

Results:

Skeletal Class II subjects with hyperdivergent facial pattern showed statistically significant narrow upper pharyngeal width when compared to normodivergent and hypodivergent facial patterns. No statistically significant difference was found in the lower pharyngeal width in all three vertical facial growth patterns.

Conclusion:

Subjects with Class II malocclusions and hyperdivergent growth pattern have significantly narrow upper pharyngeal airway space when compared to other two vertical patterns. Narrow pharyngeal airway space is one of the predisposing factors for mouth breathing and obstructive sleep apnea.

Impact of genioplasty during puberty on the upper airways

AIM

Mouth breathing is a functional disorder that affects craniofacial and dento-alveolar growth and also upper airway (UA) anatomy. This is apparent mainly in dimensional abnormalities of the UA caused by hypertrophy of Waldeyer's ring and excessive vertical development of the lower part, giving rise to labial incompetence that perpetuates the functional disorder. The main aim of this study was to evaluate the development of the oropharyngeal structures in young hyperdivergent patients who had undergone functional genioplasty in the context of orthodontic treatment.

METHODS

This is a comparative retrospective study performed on 47 adolescents who were hyperdivergent, non-obese and exclusive or diurnal mouth breathers, treated at the Centre de soins, d'enseignement et de recherche dentaires (CSERD) in Montpellier, France. All were candidates for early genioplasty for vertical reduction, and were undergoing or at the end of treatment: 23 had been treated surgically (functional genioplasty), and 24 controls had received orthodontic treatment alone. Inter-group comparison of the changes in cephalometric measurements of the oro- and nasopharyngeal zones and maxillomandibular measurements was performed using covariance analysis (ANCOVA) to adjust for confounding factors.

RESULTS

Concerning the skeletal structures: in the sagittal dimension, genioplasty led to significantly greater projection of the symphysis in the surgical group than in the control group (P<0.001). However, the sagittal position of the hyoid bone was unchanged. Similarly, in the vertical dimension, the reduction in divergence of the bony base was significantly greater in the surgical group (P<0.001), but with no change in the vertical position of the hyoid bone. Concerning the upper airways: at the level of the nasopharynx, there was a significantly greater increase in the velopharyngeal space in the surgical group (P<0.033). The same observation can be made on the level of the oropharynx, where there was a significant increase in the linguopharyngeal space in the surgical group (P<0.05), which was not the case in the control group. The change in the depth of the pharynx did not differ significantly between the two groups.

CONCLUSION

Early genioplasty performed on adolescents during the growth phase helps to recalibrate the UA by encouraging spontaneous lip closure.

Retrospective study on change in pharyngeal airway space and hyoid bone position after mandibular setback surgery

Objectives

The purpose of this study was to evaluate changes in the pharyngeal airway space and hyoid bone position after mandibular setback surgery with bilateral sagittal split ramus osteotomy (BSSRO) and to analyze the correlation between the amount of mandibular setback and the amount of change in pharyngeal airway space or hyoid bone position.

Materials and Methods

From January 2010 to February 2013, a total of 30 patients who were diagnosed with skeletal class III malocclusion and underwent the same surgery (BSSRO) and fixation method in the Division of Oral and Maxillofacial Surgery, Department of Dentistry at the Ajou University School of Medicine (Suwon, Korea) were included in this study. Lateral cephalograms of the 30 patients were assessed preoperatively (T1), immediately postoperatively (T2), and 6 months postoperatively (T3) to investigate the significance of changes by time and the correlation between the amount of mandibular setback and the amount of change in the airway space and hyoid bone position.

Results

Three regions of the nasopharynx, oropharynx, and hypopharynx were measured and only the oropharynx showed a statistically significant decrease (P<0.01). A significant posterior and inferior displacement of the hyoid bone was found 6 months after surgery (P<0.01). Analysis of the correlation between the amount of mandibular setback and the amount of final change in the airway space and hyoid bone position with Pearson's correlation showed no significant correlation.

Conclusion

In this study, the oropharynx significantly decreased after mandibular setback surgery, and changes in the surrounding structures were identified through posteroinferior movement of the hyoid bone during long-term follow-up. Therefore, postoperative obstructive sleep apnea should be considered in patients who plan to undergo mandibular setback surgery, and necessary modifications to the treatment plan should also be considered.

Changes in natural head position after orthognathic surgery in skeletal Class III patients

INTRODUCTION

The purpose of this study was to evaluate the change in natural head position (NHP) after orthognathic surgery in skeletal Class III patients.

METHODS

We used pretreatment (T1) and posttreatment (T2) cephalometric radiographs and T1 and T2 lateral facial photographs of 20 skeletal Class III patients (mean age, 21.6 years), with 20 skeletal Class I patients (mean age, 22.2 years) as the controls. The Class III patients had undergone mandibular setback surgery, and the patients in the control group had received conventional orthodontic treatment. All lateral facial photographs were recorded in NHP. The true vertical line (TVL) was transferred from the photograph to the cephalometric radiograph, and then the angle between the TVL and the Frankfort horizontal plane (TVL/FH) was measured. A t test and a paired t test were used to verify the differences between the 2 groups, and between the T1 and T2 measurements in each group.

RESULTS

The mean TVL/FH at T1 was significantly greater in the Class III group than in the Class I group; this indicated that the Class III group showed head flexion. However, the mean TVL/FH of the Class III group decreased by -3.1° at T2; this indicated head extension, and it did not significantly differ from that of the Class I group. Nineteen of the 20 Class I patients showed minimal or no change in their TVL/FH (-1.5° to 1.5°) at T2. On the other hand, 6 of the 20 Class III patients showed more than a 4.5° decrease in their TVL/FH at T2.

CONCLUSIONS

Most of the Class I patients showed minimal or no change in their NHP at T2, but some Class III patients had changes in their NHP that tended toward head extension after mandibular setback surgery. Thus, soft tissue analysis using the TVL in NHP may not be reliable for some skeletal Class III patients who undergo mandibular setback surgery.

Effects of twin-block appliance on the anatomy of pharyngeal airway passage (PAP) in class II malocclusion subjects

Background

The use of functional appliances for the correction of retrognathic mandible is very common in orthodontics. Similar appliances known as oral appliances are also frequently used in adults for the treatment of mild to moderate obstructive sleep apnea (OSA). Many studies have reported improvement of pharyngeal airway passage (PAP) dimensions following functional appliance therapy in children and oral appliance therapy in adults. There is only one study in the literature that discussed the effect of oral appliance therapy on posterior pharyngeal wall thickness (PPWT) among subjects with OSA. The effect of functional appliance therapy on PPWT has never been investigated. Thus the present study was conducted to evaluate the effects of twin-block appliance on pharyngeal airway passage (PAP) dimensions and posterior pharyngeal wall thickness (PPWT) in class II malocclusion subjects with retrognathic mandibles.

Methods

Thirty-eight class II malocclusion subjects in the age range of 8 to 14 years with mandibular retrusion were divided into a treatment (n = 20) and control (n = 18) group. Mandibular retrusion in the treatment group subjects was corrected by twin-block appliance. The effect of twin-block appliance on PAP and PPWT dimensions were evaluated from lateral cephalograms recorded prior-to and after 6 months of appliance therapy in the treatment group subjects and the changes were compared with the changes in the control group subjects. Student’s t-test was used for statistical analysis; P-value of 0.05 was considered a statistically significant level.

Results

The depth of the oropharynx was increased significantly in the treatment group subjects (P < 0.001) as compared to the control group subjects (P < 0.05). The depth of the hypopharynx increased significantly in treatment group subjects (P < 0.01). The PPWT at the level of the nasopharynx, oropharynx, and hypopharynx were maintained in the treatment group subjects; whereas in control group subjects, the PPWT was further reduced although the changes were not statistically significant.

Conclusions

Correction of mandibular retrusion by twin-block appliance in class II malocclusion subjects increased the PAP dimensions and maintained the pre-treatment thickness of posterior pharyngeal wall.

Cephalometric evaluation of tongue position and airway remodelling in children treated with swallowing occlusal contact intercept appliance (S.O.C.I.A.)

INTRODUCTION

Facial growth changes the position of the jaws (in particular vertical position of the maxilla and antero-posterior position of the mandible) and may, in turn, modify the position of the tongue and the hyoid bone, thus, generating modifications of the upper airway space. In the present paper, effects on upper airway space and tongue position of a new functional appliance, the swallowing occlusal contact intercept appliance (SOCIA) have been investigated.

MATERIALS AND METHODS

Retrospective cephaolmetric study of twenty-four children (mean age 9.46±1.60) with hyperdivergent Class II malocclusion with mandibular retrusion and atypical deglutition, was performed on radiographs taken before and after 24 months treatment with "SOCIA" appliance. The variables considered in this study, and analysed by means of a Paired t-test with a 5% level of significance, included the distance between the base of epiglottis (EB) and the tip of the tongue (TT), the distance from the tongue dorsum to EB-TT (TGH), the distance between the posterior nasal spine PNS and EB (VAL), SPAS, MAS and IAS (i.e. superior, medium and inferior pharyngeal airspace width).

RESULTS

Our findings showed a significant increase in tongue length (TT-EB) and tongue height (TGH); thus, confirming the reposition of the tongue from a lower posture to its physiological position onto the palatal spot. These modifications of the tongue posture had effects on the upper airway space. The most important modifications were observed in SPAS, with a significant 5.9 mm increase. Some increase was found also for MAS (0.83 mm) and IAS (1.1 mm) but without statistical significance. A significant increase (7.75 mm) was also found for VAL, probably as a result of the augmentation of posterior facial height.

CONCLUSIONS

SOCIA appliance is capable to improve tongue position and the superior posterior airway space, and, consequently, to improve deglutition, phonation and respiratory function.

Evaluation of airway dimensions and changes in hyoid bone position following class II functional therapy with activator

AIM

The aim of this study was to evaluate the long-term effects of Class 2 functional treatment on airway dimensions and positional changes in hyoid bone and compare it with that of an untreated Class 2 control group.

METHODS

Lateral cephalograms of 16 patients (eight girls, eight boys, mean chronological age = 11.36 ± 0.77 years) who were treated with activator and 19 patients (11 girls, eight boys, mean chronological age = 12.14 ± 0.65 years) who served as control were used for linear, angular and area measurements regarding airway track and hyoid bone. Statistics. Intra-group comparisons were performed by paired t-test and Wilcoxon test, whereas independent t-test and Mann Whitney-U were used for inter-group comparisons.

RESULTS

During treatment (T2-T1), nasopharyngeal height and nasopharyngeal area increased (p < 0.05) and hyoid bone moved downward (H-SN; p < 0.001) and forward (H-C3; p < 0.01). During retention period (T3-T2); nasopharyngeal (p < 0.01) and oropharyngeal area increased (p < 0.05). H-SN (p < 0.01) and C3-H distances (p < 0.05) increased. Hyoid bone position exhibited significant changes (H-SN, p < 0.001; C3-H, p < 0.01). The increases in C3-H in long-term was more in the activator group than control (p < 0.05).

CONCLUSIONS

In growing Class 2 patients with mandibular deficiency and airway track without obstructions, functional appliance treatment provided favorable effects on nasopharyngeal and oropharyngeal area throughout the retention period.

Effects of chin advancement surgery in hyoid bone and tongue positions and in the dimension of the oropharynx

INTRODUCTION

Advancement genioplasty has been increasingly indicated for the correction of anterior mandibular deficiency as it balances the patient's profile and generates functional changes.

OBJECTIVE

Thus, the aim of this study was to assess the effects of advancement genioplasty in the oropharyngeal size and in the position of the hyoid bone and tongue.

METHODS

The sample comprised 22 lateral cephalometric radiographs of 11 individuals who had undergone advancement genioplasty alone. Eleven of these radiographs depicted the immediate preoperative period (T0) and the other 11 the postoperative period after at least four months (T1). The radiographs were scanned and exported to the Radiocef Studio 2.0® software (Radio Memory Ltda., Belo Horizonte, MG, Brazil). The landmarks were then identified and automatically measured by the program.

RESULTS

The results showed statistically significant differences between the horizontal position of the hyoid bone and tongue and in the oropharyngeal size. The hyoid bone and tongue were repositioned anteriorly after surgery (p = 0.01), thereby increasing the dimension of the oropharyngeal airspace (p = 0.01).

CONCLUSIONS

The oropharyngeal dimension increased as the tongue base and hyoid bone were repositioned more anteriorly.

Craniofacial morphologic predictors of oral appliance outcomes in patients with obstructive sleep apnea

BACKGROUND

Oral appliances (OAs) that advance the mandible can improve the intake of oxygen and reduce the number of apneic episodes in patients who have obstructive sleep apnea. Although OAs are not as effective as continuous positive airway pressure therapy, they are an important therapeutic consideration for patients with obstructive sleep apnea. However, the ability to predict efficacy of OAs is limited. The authors conducted a study to assess the value of relevant clinical and cephalometric variables that can help predict the outcome of OA use in an Asian population.

METHODS

Fifty-two Taiwanese patients consecutively treated with OAs were included in the study. Relevant clinical and cephalometric variables were determined at baseline. Treatment success was defined as a reduction of more than 50 percent in the apnea-hypopnea index and the residual apnea-hypopnea index less than 10 per hour with OAs. The predictive value of variables for treatment outcome was evaluated by means of univariate and multivariate analyses. A receiver operating characteristic curve for the multivariate logistic regression model was constructed.

RESULTS

A good outcome was found in 29 participants (56 percent). Minimal retroglossal airway, mandibular position and anterior face height were significant predictors of OA treatment success. The area under the receiver operating characteristic curve was 0.862, reflecting good model discrimination.

CONCLUSIONS

Some cephalometric variables had a predictive value for the outcome of OA use. OA treatment outcome was favorable in patients with certain craniofacial structures such as narrow minimal retroglossal airway, mandibular retrusion and short anterior face height.

CLINICAL IMPLICATIONS

Practitioners should consider OAs for treatment of patients with obstructive sleep apnea who have narrow minimal retroglossal airways, mandibular retrusion and short anterior face heights.

Effectiveness of twin-block and Mandibular Protraction Appliance-IV in the improvement of pharyngeal airway passage dimensions in Class II malocclusion subjects with a retrognathic mandible

OBJECTIVE

To test the hypothesis that twin-block and Mandibular Protraction Appliance-IV (MPA-IV) are not effective in improving the pharyngeal airway passage (PAP) dimensions among Class II malocclusion subjects with a retrognathic mandible.

MATERIALS AND METHODS

Eighty-three subjects ranging in age from 8 to 14 years were divided into four groups. Group I included 30 Class I malocclusion subjects (healthy controls); group II consisted of 16 Class II malocclusion subjects (Class II controls); group III had 16 subjects in whom Class II malocclusion was treated by MPA-IV; and the remaining 21 subjects formed group IV, whose Class II malocclusions were corrected by twin-block appliance. Lateral cephalograms recorded at the beginning of orthodontic treatment in group I subjects and at the beginning and end of follow-up/treatment with functional appliance in group II, III, and IV subjects were analyzed to determine the PAP dimensions. Paired t-test, one-way analysis of variance, and Tukey tests were applied for statistical analysis, and a P-value .05 was considered statistically significant.

RESULTS

Soft palate length was decreased significantly in group III (P < .05) and group IV (P < .001) subjects. Soft palate thickness in group IV subjects was increased significantly as compared to group II (P < .05) and group III (P < .01) subjects. The improvement in soft palate inclination in group III and group IV subjects was significant (P < .01). The oropharynx depth was increased significantly in group III (P < .05) and group IV (P < .001) subjects. The depth of the hypopharynx was increased significantly (P < .01) in group IV subjects.

CONCLUSIONS

The twin-block appliance was more efficient than the MPA-IV in the improvement of PAP dimensions among Class II malocclusion subjects with retrognathic mandible.

Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: a cone-beam computed tomography study

INTRODUCTION

Rapid maxillary expansion (RME) is known to improve nasal airway ventilation. Recent evidence suggests that RME is an effective treatment for obstructive sleep apnea in children with maxillary constriction. However, the effect of RME on tongue posture and pharyngeal airway volume in children with nasal airway obstruction is not clear. In this study, we evaluated these effects using cone-beam computed tomography.

METHODS

Twenty-eight treatment subjects (mean age 9.96 ± 1.21 years) who required RME treatment had cone-beam computed tomography images taken before and after RME. Twenty control subjects (mean age 9.68 ± 1.02 years) received regular orthodontic treatment. Nasal airway ventilation was analyzed by using computational fluid dynamics, and intraoral airway (the low tongue space between tongue and palate) and pharyngeal airway volumes were measured.

RESULTS

Intraoral airway volume decreased significantly in the RME group from 1212.9 ± 1370.9 mm(3) before RME to 279.7 ± 472.0 mm(3) after RME. Nasal airway ventilation was significantly correlated with intraoral airway volume. The increase of pharyngeal airway volume in the control group (1226.3 ± 1782.5 mm(3)) was only 41% that of the RME group (3015.4 ± 1297.6 mm(3)).

CONCLUSIONS

In children with nasal obstruction, RME not only reduces nasal obstruction but also raises tongue posture and enlarges the pharyngeal airway.

Upper airway changes in Pierre Robin sequence from childhood to adulthood

OBJECTIVES

To investigate pharyngeal airway changes in patients with Pierre Robin sequence (PRS) longitudinally from childhood to adulthood.

SETTING AND SAMPLE POPULATION

Cleft Lip and Palate Unit, Clinic of Orthodontics, University of Zurich. Twenty-four patients born between 1970 and 1990 with non-syndromic PRS.

MATERIALS AND METHODS

Lateral cephalograms at age 5 (T1), 10 (T2), 15 (T3) and 20 (T4) years were available. Variables describing pharyngeal airway dimensions, soft palate morphology, tongue and hyoid position, skeletal morphology and head posture were assessed.

RESULTS

A significant increase in nasopharyngeal depth was found over the entire observation period (T1 10.7 to T4 19.1 mm, p < 0.001), especially between T2 and T3 (change 3.8 mm, p < 0.001), and was mainly due to adenoid recession (r = -0.75, p < 0.001; variation explained by 56%). Increase in velopharyngeal depth mainly took place between T3 and T4 (change 2.3 mm, p < 0.01). It was due to more anterior tongue posture (r = 0.65, p < 0.001; 42.5% of variation explained), in turn allowing the soft palate to take a more vertical position (r = -0.52, p < 0.001). Increase in oropharyngeal depth was associated with head extension and anterior mandibular positioning (36% of variation explained). However, significance was not reached (T1 8.3 to T4 9.8 mm, p > 0.05).

CONCLUSIONS

Upper airway dimensions in children with PRS improve with time, except for the oropharyngeal airway. Despite large interindividual variation, the mean remained in the lower reaches of normality described in other studies. Thus, further research should investigate the prevalence of obstructive sleep apnoea in adults with PRS.