Orofacial airway dimensions in subjects with Class I malocclusion and different growth patterns

Using a Portable Ventilatory Airway Screening (PVAS) Device to Evaluate the Difference Between Upper Airway Breathing Pressure and Respiratory Flow in Skeletal Class I and Class II Growing Individuals With Retrognathic Mandible

Background Upper airway obstruction (UAO) is a significant clinical concern due to its potential to lead to serious health issues, including obstructive sleep apnea (OSA) and cardiovascular diseases. Traditional diagnostic methods, such as spirometry, are often invasive and complex. This study aims to validate a portable ventilatory airway screening (PVAS) device as a non-invasive, cost-effective alternative for measuring upper airway breathing pressure and respiratory flow. Objectives To validate the accuracy of the PVAS device in measuring upper airway breathing pressure and respiratory flow by comparing its readings with those obtained from standard spirometry tests. Methods This cross-sectional analytical study involved 40 growing individuals aged 10-14 years, divided into two groups based on cephalometric analysis: Skeletal Class I (20 patients) and Skeletal Class II with retrognathic mandible (20 patients). Breathing pressure, volume, and velocity measurements were recorded using both the PVAS device and spirometry, and their accuracy was compared. Results The PVAS device showed high concordance with spirometry results, demonstrating significant accuracy in measuring breathing pressure, volume, and velocity. Skeletal Class II individuals exhibited significantly higher breathing pressure and reduced respiratory flow compared to Class I individuals, as measured by the PVAS device. Conclusion The PVAS device is a valid and accurate tool for non-invasive measurement of upper airway breathing pressure and respiratory flow. Its ease of use and reliability make it a valuable tool for clinical practice, particularly in the early diagnosis and management of airway obstructions.

Assessment of maximal inspiratory and expiratory pressures in skeletal Class II patients with different growth patterns

OBJECTIVES

To evaluate maximal inspiratory (MIP) and expiratory (MEP) pressures, which are reflective of respiratory muscle strength, in skeletal Class II patients with different growth patterns (horizontal, average, and vertical) and to correlate those with airway dimension.

MATERIALS AND METHODS

Patients with a Class II skeletal base seeking orthodontic treatment were assigned to the following groups: average, horizontal, and vertical growth pattern. The control group (n = 14) comprised patients with a Class I skeletal base and average growth pattern. Airway dimensions were obtained using cone-beam computed tomography scans, and a spirometer with a pressure transducer was used for assessment of MIP and MEP. Routine spirometry for assessment of lung function was also performed.

RESULTS

No significant differences were found in maximal inspiratory and expiratory pressures for the study groups in comparison with the control group. Class I patients had significantly greater oropharyngeal and nasopharyngeal airway volumes compared with the study groups. No significant difference in minimal cross-section area of the airway was observed among groups. A weak positive correlation between maximal inspiratory pressure and airway volume was observed.

CONCLUSIONS

Although Class I patients displayed significantly greater oropharyngeal and nasopharyngeal airway volumes, there was no significant difference in respiratory muscle strength or airway function between Class II patients with different growth patterns and the Class I control group. The findings underscore the significance of exploring factors beyond craniofacial growth patterns that may contribute to sleep-related breathing disorders.

Three-dimensional evaluation of the pharyngeal airway space in patients with anterior open bite

Objective

: This study aimed to three-dimensionally evaluate the pharyngeal airway space (PAS) of patients with anterior open bite (AOB) by using cone-beam computed tomography (CBCT) and compare the findings with those obtained in individuals with normal occlusion.

Methods

: The open bite group (OBG, n = 25) consisted of patients with an anterior overbite of -3 mm or less, while the control group (n = 25) consisted of age- and sex-matched individuals with an anterior overbite of 1-3 mm, Angle Class I malocclusion (1° ≤ point A-nasion-point B angle ≤ 4°), and a normodivergent profile (22° ≤ Frankfort mandibular plane angle ≤ 28°). After the CBCT data were reconstructed into a three-dimensional image, the PAS was segmented into four parts, and the volume of each part was measured. Pharyngeal airway length (PAL) and the area and transverse width of the part showing minimal constriction were also measured. Pearson's correlation analysis was used to evaluate the correlation between changes in the PAS and the amount of anterior overbite.

Results

: The OBG showed a significantly narrower airway space in the nasopharyngeal, hypopharyngeal, and total airway volumes. The OBG also showed a significantly smaller area and transverse width of the part with minimal constriction. The OBG showed a significantly longer PAL, but there was no correlation between the amount of anterior overbite and the changes in PAS.

Conclusions

: The PAS was associated with AOB. Patients with AOB had a narrower PAS and a smaller part showing minimal constriction.

Three-dimensional assessment of Upper Airway in Class III patients with different facial patterns

Background

To evaluate three-dimensionally the upper airway (UA) of class III adults with different facial patterns.

Material and Methods

A cross-sectional study was conducted, in which cone-beam computed tomography (CBCT) images from a private clinic in Viña del Mar, Chile were evaluated. The sample consisted of CBCT images of 59 skeletal class III subjects (33 females and 26 males, mean age 24.7 years) in which the vertical facial pattern was determined using the Vert index, and the minimum cross-sectional area and total volume of the UA were measured. The minimum cross-sectional area variable was analyzed by ANOVA and the total volume was analyzed by Kruskal-Wallis test. Statistical analyses were performed with JASP 0.13.1 software at p=0.05.

Results

The sample included images of 21 brachyfacial, 14 mesofacial and 24 dolichofacial subjects. The mean minimum cross-sectional area of the sample was 591.78 mm2 +/- 149.38 mm2 (minimum=352.00 mm2; maximum=971.00 mm2), being greater in brachyfacial than in dolichofacial and mesofacial subjects, however, these differences were not significant (p=0.147). The mean total volume of the sample was 13.40 +/- 4.69 cm3 (minimum=7.16 cm3; maximum=25.66 cm3), being greater in brachyfacial than in dolichofacial and mesofacial subjects, however, these differences were not significant (p=0.353).

Conclusions

Considering the limitations of the present study, the vertical facial pattern does not appear to significantly influence upper airway measurements in skeletal class III adults. Key words:Airway, cephalometry, cone-beam computed tomography, facial pattern, malocclusion, Angle class III.

[Comparison of pharyngeal airway space on lateral head radiographs of skeletal class I and II individuals]

Objective

To compare the space of the pharyngeal airway (nasopharynx and oropharynx) through lateral X-ray analysis in skeletal class II individuals with a control group composed of skeletal class I individuals.

Materials and methods

This study was of the observational, descriptive, transversal, and prospective type. The sample was made up by 60 lateral head radiographs distributed between 30 class I (ANB 2°±2° and class I malocclusion) and 30 skeletal class II radiographs (ANB>5° and malocclusion class II-1). Measurements of the airway space in the oropharynx and nasopharynx were taken in mm through the McNamara method on lateral head radiographs.

Results

The average space found in the oropharynx in class I was 11.71mm ± 3.18mm. In the class II group, it was 10.73mm ± 2.36mm. No significant differences were found (p=0.18). The average space found in the nasopharynx in the class I group was 18.45mm ± 4.11mm. In the class II group, it was 19.10mm ± 3.89mm. There were no significant differences found (p=0.53).

Conclusion

The airway space in mm. of the nasopharynx presents similar values in millimeters in subjects with Class I and Class II skeletal malocclusion. There is no difference in the airway spaces of the oropharynx in subjects with Class I and Class II Malocclusions.

Heritability of cephalometric variables of airway morphology in twins with completed active growth

BACKGROUND

The interplay between genetic and environmental impacts on dental and facial morphology has been widely analyzed, but little is known about their relative contributions to airway morphology. The aim of this study was to evaluate the genetic and environmental influences on the cephalometric variables of airway morphology in a group of postpubertal twins with completed craniofacial growth.

MATERIALS AND METHODS

The materials comprised lateral head cephalograms of 94 pairs of twins (50 monozygotic, 44 dizygotic) with completed craniofacial growth. Zygosity was determined using 15 specific DNA markers. The computerized cephalometric analysis included 22 craniofacial, hyoideal, pharyngeal structural linear and angular variables. Genetic analysis and heritability estimation were performed using maximum likelihood genetic structural equation modeling (GSEM). Principal component analysis (PCA) was used to assess the correlations between cephalometric measurement variables.

RESULTS

Upper airway dimensions showed moderate to high genetic determination (SPPW-SPP and U-MPW: a2 = 0.64 and 0.5, respectively). Lower airway parameters showed only common and specific environmental determination (PPW-TPP a2 = 0.24, e2 = 0.38; LPW-V c2 = 0.2, e2 = 0.63; PCV-AH c2 = 0.47, e2 = 0.28). The relationship between the maxilla and the hyoid bone (for variables PNS-AH, ANS-AH d2 = 0.9, 0.92, respectively) showed very strong additive genetic determination. The size of the soft palate was affected by additive and dominant genes. Its length (SPL) was strongly influenced by dominant genes, while its width (SPW) showed a moderate additive genetic influence. Owing to correlations in the behavior of variables, the data could be expressed in 5 principal components that jointly explained 36.8% of the total variance.

CONCLUSIONS

The dimensions of the upper airway are strongly determined by genes, while the parameters of the lower airway depend mainly on environmental factors.

TRIAL REGISTRATION

The protocol has been approved by the Kaunas Regional Ethical Committee (No. BE - 2-41., May 13, 2020).

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

OBJECTIVES

This study aimed to determine the three-dimensional (3D) correlation between maxillomandibular complex parameters and pharyngeal airway dimensions in different sagittal and vertical malocclusions.

METHODS

This retrospective cross-sectional study included the CBCT scans of 368 patients with a mean age of 23.81 ± 3.01 years. The patients were classified into three groups (skeletal Class I, II, and III). Each class group was divided into three subgroups based on vertical growth patterns (hypo-, normo-, and hyperdivergent). The maxillomandibular complex was evaluated in the three planes using 16 skeletal measurements. Naso-, oro-, hypo-, and total pharyngeal airway spaces were assessed in terms of width, volume, surface area, and minimum constricted area (MCA). Two-way ANOVA followed by the Bonferroni post-hoc test were used.

RESULTS

The nasopharyngeal airway space was significantly lowest regarding sagittal and lateral widths in the skeletal Class III patients, the lowest volume and surface area were in hyperdivergent patients, and MCA was the highest in Class II and hypodivergent patients. The oro- and hypopharyngeal sagittal width, volume, surface area, and MCA were the lowest in the hyperdivergent patients, and oropharyngeal lateral width and hypopharyngeal sagittal width were the highest in skeletal Class III. The total pharyngeal volume, surface area, and MCA were the lowest in the hyperdivergent patients, and skeletal Class II patients had the lowest MCA.

CONCLUSIONS

The pharyngeal airway dimensions differ with various sagittal and vertical malocclusions. These differences could apply to diagnosis, treatment planning, and possible changes following orthodontic/orthopedic or surgical treatment.

Assessment of Dentofacial Characteristics and Pharyngeal Airway in Children with Class II Malocclusion and Mouth Breathing

Background In growing patients with skeletal discrepancies, early diagnosis, evidence-based explanation of etiology, and assessment of functional factors can be vital for the restoration of normal craniofacial growth and the stability of treatment needs.

Aims The aim of the study was to assess dentofacial characteristics as well as upper and lower pharyngeal airway in children with skeletal class II malocclusion with mouth breathing, and to investigate possible significant relationships and correlations among the studied cephalometric variables and the airway morphology in these children.

Materials and Methods Sixty untreated children, aged 9 to 13 years, were divided into three groups according to clinical findings and cephalometric analysis of dentofacial characteristics as well as the presence of mouth breathing habit: Group I (20 children with normal jaw relation/class I), Group II (20 children with skeletal class II), and Group III (20 children with skeletal class II with confirmed mouth breathing habit). Cephalometric variables and upper/lower airway widths were recorded. Intergroup comparison of all measurements was performed by post hoc Tukey test, and Pearson's correlation was used to determine the correlation among the variables.

Results Significant changes existed in more than half of the dentofacial measurements among the three groups. Significantly greater skeletal anteroposterior jaw discrepancy and mandibular retrognathism were found in both groups II and III as determined by specific anteroposterior determinants. Children in group III showed significantly increased angle between Sella-Nasion and mandibular plane (SN-MP) angle, y-axis, and a vertical growth pattern. Significant increases in dental measurements, namely upper incisor to Nasion- point A (NA), lower incisor to Nasion - point B (NB), and overjet, were found in group II and group III, while overbite showed a significant decrease. Upper pharyngeal airway width was found to be significantly decreased in group III followed by a smaller though significant decrease in group II. No significant differences were found in lower pharyngeal airway width between the groups. There were statistically significant dentofacial characteristics that showed fair to good correlation with the upper airway width.

Conclusion Children with skeletal class II malocclusion with and without mouth breathing showed significant differences in dentofacial measurements and a significantly narrower upper pharyngeal airway as compared with children with normal jaw/class I relation.

Evaluation of pharyngeal airway and hyoid bone position in skeletal Class 1 individuals with different vertical growth patterns in Turkish population

Amaç: Bu araştırmada, iskeletsel Sınıf 1 ilişkiye sahip bireylerde dik yön büyüme paterninin farengeal havayolu boyutlarına ve hyoid kemik pozisyonuna etkisinin değerlendirilmesi amaçlanmıştır. Gereç ve Yöntem: Bu retrospektif araştırmaya, ANB açısı temel alınarak iskeletsel Sınıf 1 ilişkiye sahip toplam 72 birey (36 kadın, 36 erkek; ortalama yaş: 17.78 ± 1.39 yıl) dahil edildi. Bireyler dik yön büyüme paternine göre; normodiverjan, hipodiverjan ve hiperdiverjan olmak üzere 3 gruba ayrıldı. Lateral sefalometrik radyografiler üzerinde farengeal havayolu ve hyoid kemik pozisyonu ölçümleri, 1 açısal ve 10 lineer ölçüm kullanılarak yapıldı. Verilerin analizinde bağımsız örneklem t-testi ve tek yönlü varyans analizi (ANOVA) kullanılarak grup içi ve gruplar arası farklılıklar değerlendirildi (p<0.05). Bulgular: Verilerin grup içi karşılaştırmalarında farengeal havayolu boyutlarına ait ölçümlerin cinsiyetler arasında benzer olduğu (p˃0.05) ve tüm gruplarda hyoid kemiğin servikal vertebralara ve mandibular düzleme olan uzaklıklarının kızlarda anlamlı düzeyde daha az olduğu görüldü (p<0.05). Normodiverjan, hipodiverjan ve hiperdiverjan bireylerin farengeal havayolu boyutları ve hyoid kemik pozisyonunda istatistiksel olarak anlamlı farklılıklar olmadığı belirlendi. Sonuç: Normodiverjan, hipodiverjan ve hiperdiverjan bireylerde farengeal havayolu boyutlarının ve hyoid kemik pozisyonlarının benzer olduğu görüldü. Bununla birlikte, tüm gruplarda erkeklerde hyoid kemiğinin kızlara göre daha aşağıda ve daha önde pozisyonlandığı belirlendi.

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.

X-Ray Cephalometric Analysis of the Effects of Angle Class II and III Malocclusion on the Upper Airway Width and Hyoid Position between Parents and Children of Uygur Nationality

Objective

The objective of this paper is to analyze the effect of angle class II and III malocclusion on the sagittal diameter of the upper airway between parents and children of Uygur nationality and to compare the degree of influence.

Methods

29 Uygur adolescents with malocclusion and their fathers (mothers) were selected as our subjects via X-ray cephalometric radiograph to analyze the difference between the upper airway sagittal dimension and normal occlusion and compare the influence of malocclusion on the upper airway between parents and children.

Results

Compared with normal group, the vertical distance from the hyoid point to orbital-ear plane (H-FH) and vertical distance from hyoid point to the mandibular plane (H-MP) in angle class II malocclusion elevated signally, while the vertical distance from hyoid point to anterior cervical plane (H-VL), PNS-UPW, H-FH, and H-MP decreased significantly; compared with normal group: the distance between the posterior nasal spine and the upper pharynx wall (PNS-UPW), H-FH, and H-MP in angle class III malocclusion visually reduced, while PAS, and horizontal distance from the hyoid point and center point of sella turcica to orbital-ear foot (H-S), increased markedly. The impact of class II malocclusion on parents' U-MPM was greater than their children.

Conclusion

The oropharyngeal space of upper airway becomes smaller and hyoid shifts downwards due to class II malocclusion. Class III malocclusion results in decreased nasopharyngeal gap with hyoid to shift upward. The influence of class II malocclusion on the upper pharyngeal tract of parents was greater than their children.

Pharyngeal Airway Space Dimensions and Hyoid Bone Position in Various Craniofacial Morphologies

Objective:

To assess the relationship of pharyngeal airway dimensions and the position of the hyoid bone in several craniofacial morphologies among Nepali adults. To assess the relationship between dimensions of the pharyngeal airway and position of the hyoid bone and compare gender dimorphism.

Materials and Methods:

The cross-sectional observational research comprised lateral cephalograms of 150 subjects aged 16 to 30 years. Samples were separated into three sagittal craniofacial morphological groups based on the ANB (A point, nasion, B point) angle and into gender groups. Different parameters (linear and angular) for measuring dimensions of the pharyngeal airway and position of the hyoid bone were assessed. An ANOVA test and a Pearson correlation test were performed.

Results:

Dimensions of the pharyngeal airway were largest in skeletal Class III when compared to skeletal Class I and Class II subjects, with a lower pharyngeal airway space and the length of the nasal fossa being significantly larger. The hyoid bone was anteriorly and inferiorly placed in Class III skeletal subjects. Males had greater pharyngeal airway dimensions and a hyoid bone positioned more inferiorly and anteriorly. The nasal fossa length had a strong positive correlation with the hyoid bone position vertically.

Conclusion:

There were differences in the dimensions of the pharyngeal airway and position of the hyoid bone in various craniofacial morphologies among Nepali adults. Gender dimorphism was observed in both dimensions of the pharyngeal airway and the position of the hyoid bone.

Effect of extraction treatment on upper airway dimensions in patients with bimaxillary skeletal protrusion relative to their vertical skeletal pattern

Objective

To investigate dimensional changes in regional pharyngeal airway spaces after premolar extraction in bimaxillary skeletal protrusion (BSP) patients according to vertical skeletal pattern, and to further identify dentoskeletal risk factors to predict posttreatment pharyngeal changes.

Methods

Fifty-five adults showing BSP treated with microimplant anchorage after four premolar extractions were included in this retrospective study. The subjects were divided into two groups according to the mandibular plane steepness hyperdivergent (Frankfort horizontal plane to mandibular plane [FH-MP] ≥ 30) and nonhyperdivergent groups (FH-MP < 30). The control group consisted of 20 untreated adults with skeletal Class I normodivergent pattern and favorable profile. Treatment changes in cephalometric variables were evaluated and compared. The association between posttreatment changes in the dentoskeletal and upper airway variables were analyzed using linear regression analysis.

Results

The BSP patients showed no significant decrease in the pharyngeal dimensions to the lower level in comparison with controls, except for middle airway space (MAS, p < 0.01). The upper airway variable representing greater decrease in the hyperdivergent group than in the nonhyperdivergent group was the MAS (p < 0.01). Posttreatment changes in FH-MP had negative correlation with changes in MAS (β = –0.42, p < 0.01) and inferior airway space (β = –0.52, p < 0.01) as a result of multivariable regression analysis adjusted for sagittal skeletal relationship.

Conclusions

Decreased pharyngeal dimensions after treatment in BSP patients showed no significant difference from the normal range of pharyngeal dimensions. However, the glossopharyngeal airway space may be susceptible to treatment when vertical dimension increased in hyperdivergent BSP patients.

Validation of manufacturers' laryngeal mask airway size selection standard: a large retrospective study

Background

Laryngeal mask airway (LMA) is a prominent supraglottic airway device, widely used especially in difficult airway management. However, the LMA sizes recommended by the manufacturers are not always well matched in clinical practice, which leads to complications. To date, there are rare models to validate whether the manufacturers’ standard is suitable for use in clinical practice.

Methods

A total of 58,956 patients undergoing general anesthesia using LMA device were included in the study between January 1, 2011 and December 31, 2018, to validate the adherence rate of LMA sizes according to the manufacturers’ recommendations. A logistic regression analysis was performed based on the actual LMA size used in clinical practice to establish separately size selection guidelines with gender, weight, and age as variables in adults, adolescents, and children.

Results

LMA insertions were analyzed in 50,776 (86.1%) adults, 3,548 (6%) adolescents, and 4,632 (7.9%) children. Suitability of manufacturers’ recommendations was higher in children [male: 86.02%; female: 85.09%] than adults [male: 72.75%; female: 78.13%] or adolescents [male: 73.4%; female: 70.79%]. For adults and adolescents, LMA size was better predicted using the regression model rather than the manufacturers’ recommendations [male adults: 82.4% (81.16–83.57%) vs. 73.21% (71.79–74.59%), P<0.05; female adults: 87.82% (86.65–88.9%) vs. 77.07% (75.6–78.48%), P<0.05; male adolescents: 79.45% (74.86–83.4%) vs. 72.05% (67.09–76.53%), P<0.05; female adolescents: 78.4% (71.11–84.31%) vs. 72.22% (64.54–78.82%), P<0.05]. For children, there was equal performance suitability using the regression model and the manufacturers’ recommendations.

Conclusions

The model-based guidelines may provide more accurate directions for LMA size selection for adolescents and adults than the manufacturers’ weight-based recommendations, whereas the manufacturers’ recommendation in children is consistent with clinical practice.

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

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

Risk factors for anterior open bite: A case-control study

BACKGROUND

Anterior open bite (AOB) is noteworthy because it is a complex dysplasia, and clinical studies on this malocclusion are usually epidemiological studies or experimental models with small samples and no control group, which renders the data on AOB incomplete and therefore inconclusive. The objective this study was to assess the risk factors involved in developing AOB.

MATERIALS AND METHODS

A case-control study was provided with a total of 96 lateral cephalometric radiographs of male and female patients aged between 8 and 14 years were used, regardless of facial type. The dependent variable was the presence or absence of AOB, which divided the participants into case and control groups, respectively; these groups were matched for gender and age. The case and control groups data were analyzed by descriptive and inferential analysis by binary logistic regression using at the 5% significance level.

RESULTS

The occurrence of AOB was associated with the presence of deleterious oral habits (P = 0.014; Chi-square test) and was approximately three times (odds ratio = 3.04) more likely to occur in participants with AOB. No significant association between the presence of mouth breathing and the occurrence of AOB was found (P = 0.151; Chi-square test). The odds associated with tongue interposition were 10.51 times higher than those of participants with no such deglutition. The odds associated with the dolichofacial pattern were 5.74 times those of participants with a nondolichofacial pattern.

CONCLUSION

Tongue interposition and dolichocephalic facial pattern were risk factors for developing AOB.

Assessment of airway dimensions in skeletal Class I malocclusion patients with various vertical facial patterns: A cephalometric study in a sample of the Saudi population

OBJECTIVE

To compare airway widths among skeletal Class I malocclusion patients with different vertical facial patterns.

MATERIAL AND METHODS

A total of 103 lateral cephalograms of skeletal Class I patients (mean age of 20 ± 2.3 years) with no history of orthodontic treatment, trauma, facial syndromes, or nasopharyngeal dysfunction were included. Based on the Frankfort-mandibular plane angle measurements, the sample was divided into three groups: low-angle, high-angle, and normal-angle groups. Upper and lower pharyngeal airway widths were measured as described by McNamara. The analysis of variance test was performed to compare the means of groups. Pairwise comparisons were performed using Tukey's post-hoc test. Differences were considered statistically significant at P < 0.05.

RESULTS

ANOVA showed a significant mean difference between the groups for both the upper and lower airway widths with P values of 0.011 and 0.003, respectively. Tukey Pairwise comparisons showed the upper airway width to be significantly narrower in the high-angle group compared to the normal-angle (P = 0.021) and low-angle groups (P = 0.013). Furthermore, the lower airway width in the high angle group was significantly narrower than the normal angle (P = 0.020) and low-angle groups (P = 0.017). There were no statistically significant differences between normal and low angle groups.

CONCLUSIONS

The upper and lower pharyngeal widths in the Class I high-angle group were significantly narrower than those in the normal-angle and low-angle groups.

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.

Upper airways evaluation in young adults with an anterior open bite: A CBCT retrospective controlled and cross-sectional study

OBJECTIVE

To compare the dimensions of the upper airway in young adults with anterior open bite versus matched individuals with an adequate overbite (control group) using different measurement approaches (linear, area, and volume measures).

MATERIALS AND METHODS

The sample included 137 cone-beam computed tomographies (CBCTs) of young adults (74 men and 63 women) divided into two groups: 47 CBCTs of individuals (mean age 27.89) with open bite (overbite depth indicator (ODI) 56.84°±9.48° and Frankfort mandibular plane angle (FMA) 31.21°±6.44°) and 90 CBCTs of individuals (mean age 26.87) without an open bite (ODI 62.24°±9.47°, FMA 26.79°±5.81°). Two trained and calibrated orthodontists made all linear, area, and volume measurements on the CBCT records of the upper airways using Planmeca Romexis software. The Mann-Whitney U-test, chi-squared test, and multiple linear regression were applied. Significance was set at P<0.05.

RESULTS

There were no differences in linear or volume measurements between groups, but there was a greater area in the open bite group (greater mean difference between groups 928.3 mm²) than the control group. No variable influenced nasopharyngeal airway volume, but ANB angle affected oropharyngeal airway volume (β=-623.87) and total airway volume (β=-651.48).

CONCLUSIONS

Orthodontists should be aware that the airways diagnosis can vary depending on the measurement approach used, the volumetric method being the gold standard. The pharyngeal airway volume was similar in individuals with vs. without an open bite and is mainly influenced by ANB angle in both groups.

Analysis of the middle region of the pharynx in adolescents with different anteroposterior craniofacial skeletal patterns

Objective:

To assess the volume and morphology of the middle region of the pharynx (MRP) in adolescents with different anteroposterior craniofacial skeletal patterns.

Methods:

One hundred twenty-six patients (56 male and 70 female), who had cone-beam computed tomography (CBCT) within their records, were selected for this cross-sectional study. Participants were classified, according to their ANB angle value, in Class I (1^o ≤ ANB ≤ 3^o), Class II (ANB > 3^o) and Class III (ANB < 1^o). The total volume (tV), minimum axial area (AxMin) and morphology of the MRP and its subdivisions - velopharynx (VP) and oropharynx (OP) - were characterized by CBCT and 3-dimensional image reconstruction software. Intergroup comparisons were performed by ANOVA and Tukey post-hoc tests. Correlations between tV and Axmin with the ANB angle values were tested using linear regression analysis, considering sex as covariable.

Results:

Statistically significant difference between groups were observed in tV only for the VP region; Class II individuals presented significantly lower tV (6863.75 ± 2627.20 mm³) than Class III subjects (9011.62 ± 3442.56 mm³) (p< 0.05). No significant differences were observed between groups for any other variable assessed, neither in MRP nor in the OP region (p> 0.05). A significant negative correlation was evidenced between tV and Axmin and the ANB angle values; sexual dimorphism was observed for some variables.

Conclusions:

Class II subjects have smaller tV in the VP region. tV and Axmin tend to decrease in all evaluated regions when the ANB angle values increase.

Cephalometric Evaluation of the Upper Airway in Different Skeletal Classifications of Jaws

BACKGROUND

Respiratory system is an important section in development of maxillofacial components and many studies indicated its effect on normal growth of the jaws. The aim of this study is to evaluate upper airway in different skeletal classifications of jaws in lateral cephalogram and its relation to age and gender.

MATERIALS AND METHODS

Study samples were 105 digital cephalometric radiographies, 72 females and 33 males. Lateral cephalograms were hand traced and based on Stainer analysis, there were 30 samples in Class I, 30 samples in Class II and 45 samples in Class III subgroup. Vertical linear measurements, horizontal linear measurements, and angular measurement, proportions and space measurements of the airway in the Cephalograms were analyzed by AutoCAD software.

RESULTS

Data were analyzed using SPSS software version 20. Two horizontal linear measurement (the hypo pharyngeal airway depth, the nasopharyngeal airway depth) and one space measurement (soft palate space) were significantly different in skeletal classes. Vertical and horizontal linear measurements in the 3 groups were increased significantly in men rather than women. The developmental age of groups showed some significant differences.

CONCLUSION

Upper airway dimension is different in different skeletal classes, developmental ages, and gender.

Pharyngeal airway spaces in different skeletal malocclusions: a CBCT 3D assessment

Objective: To three-dimensionally evaluate the upper pharyngeal airway spaces in adults with different anteroposterior and vertical skeletal malocclusions.Methods: In this retrospective study, three-dimensional airway volume and the minimum constricted areas of 120 adults were measured from cone beam computed tomography volume scans. The sample was divided into skeletal Class I and Class II and subdivided into average and long face malocclusions in each skeletal Class. Airway volumes of the naso-, palato-, and glossopharynx, and the minimum constricted area were measured and compared.Results: Skeletal Class II reduced glossopharyngeal airway volume and larger total minimum constricted area in average faces and more nasal minimum constricted area in long faces. Skeletal Class II with long face significantly increased palatopharyngeal and glossopharyngeal airway volumes as well as larger palatopharyngeal minimum constricted area (p < 0.05).Conclusion: This paper found a likely association between jaw skeletal classification and airway dimensions.

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.

Three-dimensional study of the upper airway in different skeletal Class II malocclusion patterns

OBJECTIVES

To characterize upper airway volume and morphology in patients with different skeletal patterns of Class II malocclusion compared to Class I.

MATERIALS AND METHODS

A total of 197 individuals who had cone-beam computed tomography were allocated into groups according to ANB, SNA, and SNB angles (Class I, Class II maxillary protrusion, Class II mandibular retrusion), each subdivided into hypodivergent, normal, and hyperdivergent. Nasopharynx (NP), oropharynx (OP), and hypopharynx (HP) were assessed with three-dimensional image reconstruction software.

RESULTS

Intergroup comparison did not detect significant differences in volume and morphology of NP, OP, and HP. The males displayed larger OP and HP volume than the females. Positive correlations between age and NP, OP, HP volume and between craniocervical angle and OP and HP volume were observed. Linear regression analysis detected a tendency for OP and HP volume to increase as maxillary and mandibular length increased.

CONCLUSIONS

Upper airway volume and morphology were similar in different skeletal patterns of Class II malocclusion. Actual upper and lower jaw lengths were more closely related to upper airway volume and morphology than the angles that reflected their position relative to the cranial base.

Airway increase after open bite closure with temporary anchorage devices for intrusion of the upper posteriors: Evidence from 2D cephalometric measurements and 3D magnetic resonance imaging

OBJECTIVE

The aim of this study was to analyse morphological changes in the upper airways in patients with anterior open bite treated with temporary anchorage devices for intrusion of upper posterior teeth.

MATERIALS AND METHODS

Twelve nonobese (body mass index: <25) anterior open bite patients between the ages of 19 and 44 years (mean age: 22.83 ± 8.19 years) were recruited for this study. Cephalometric radiographs and magnetic resonance imaging (MRI) scans before and after anterior bite closure without bracketing on anterior teeth were used to measure the upper airway, which was divided into retropalatal and retroglossal regions.

RESULTS

The mandibular plane angle and lower facial height were significantly reduced by intrusion of the upper posteriors and autorotation of the mandible. The retroglossal airway width (AW2) and retroglossal area (RG area) measured on cephalometric radiographs both increased significantly after treatment. Retroglossal volume increased and the retroglossal width/length ratio decreased significantly in MRI analysis. All other measurements were not significantly changed. However, no statistically significant correlations were observed between all measurements in 2D and 3D images, with the exception of the AW2 linear measurement in 2D images correlating with the AP length in MRI axial view images (r = 0.56, P = 0.0430).

CONCLUSION

Counterclockwise rotation of the mandible after anterior open bite closed using orthodontic treatment changed the airway morphology. Retroglossal volume significantly increased and the airway shape became less elliptical after bite closure.

Comparison between Growth Patterns and Pharyngeal Widths in Different Skeletal Malocclusions in South Indian Population

Aim:

The main aim is to determine whether growth pattern had an effect on the upper airway by comparing different craniofacial patterns with pharyngeal widths and its importance during the clinical examination.

Methodology:

Sixty lateral cephalograms of patients aged between 16 and 24 years with no pharyngeal pathology or nasal obstruction were selected for the study. These were divided into skeletal Class I (n = 30) and skeletal Class II (n = 30) using ANB angle subdivided into normodivergent, hyperdivergent, and hypodivergent facial patterns based on SN-GoGn angle. McNamara's airway analysis was used to determine the upper- and lower-airway dimensions. One-way ANOVA was used to do the intergroup comparisons and the Tukey's test as the secondary statistical analysis.

Results:

Statistically significant difference exists between the upper-airway dimensions in both the skeletal malocclusions with hyperdivergent growth patterns when compared to other growth patterns.

Conclusion:

In both the skeletal malocclusions, vertical growers showed a significant decrease in the airway size than the horizontal and normal growers. There is no statistical significance between the lower airway and craniofacial growth pattern.

Assessment of upper airways measurements in patients with mandibular skeletal Class II malocclusion

Objective:

Mandibular Class II malocclusions seem to interfere in upper airways measurements. The aim of this study was to assess the upper airways measurements of patients with skeletal Class II malocclusion in order to investigate the association between these measurements and the position and length of the mandible as well as mandibular growth trend, comparing the Class II group with a Class I one.

Methods:

A total of 80 lateral cephalograms from 80 individuals aged between 10 and 17 years old were assessed. Forty radiographs of Class I malocclusion individuals were matched by age with forty radiographs of individuals with mandibular Class II malocclusion. McNamara Jr., Ricketts, Downs and Jarabak's measurements were used for cephalometric evaluation. Data were submitted to descriptive and inferential statistical analysis by means of SPSS 20.0 statistical package. Student's t-test, Pearson correlation and intraclass correlation coefficient were used. A 95% confidence interval and 5% significance level were adopted to interpret the results.

Results:

There were differences between groups. Oropharynx and nasopharynx sizes as well as mandibular position and length were found to be reduced in Class II individuals. There was a statistically significant positive correlation between the size of the oropharynx and Xi-Pm, Co-Gn and SNB measurements. In addition, the size of the nasopharynx was found to be correlated with Xi-Pm, Co-Gn, facial depth, SNB, facial axis and FMA.

Conclusion:

Individuals with mandibular Class II malocclusion were shown to have upper airways measurements diminished. There was a correlation between mandibular length and position and the size of oropharynx and nasopharynx.

Comparison of airway dimensions in skeletal Class I malocclusion subjects with different vertical facial patterns

OBJECTIVE

The aim of this study was to compare upper airway widths among skeletal Class I malocclusion subjects with different vertical facial patterns.

METHODS

The sample included a total of 99 lateral cephalograms of post pubertal individuals (18.19 ± 1.76 years old). The vertical facial pattern was determined by the Vert index. The McNamara method was used to quantify upper airway widths. ANOVA test and Student's t test for independent groups were used, when normal distribution was not supported Kruskal-Wallis test and U-Mann-Whitney test were used. A multiple linear regression analysis was also performed.

RESULTS

Statistically significant differences in several nasopharyngeal widths were found among the distinct vertical facial patterns. Subjects with brachyfacial pattern presented larger nasopharyngeal widths than subjects with mesofacial (p= 0.030) or dolichofacial (p= 0.034) patterns. The larger the Vert value, the larger the nasopharyngeal widths (R2= 26.2%, p< 0.001). At the level of oropharynx no statistically significant differences were found.

CONCLUSION

It was concluded that nasopharyngeal linear anteroposterior widths in Class I malocclusion brachyfacial are larger than in mesofacial and dolichofacial individuals. The Vert index only explained 25% of the total variability. No correlation was found for the oropharyngeal widths.

Upper airway asymmetry in skeletal Class III malocclusions with mandibular deviation

The purpose of this study was to investigate the relationship between bilateral differences of upper airway and mandibular morphologic patterns in subjects with skeletal Class III mandibular deviation. 47 skeletal Class III (ANB < 0°) adult patients with and without mandibular deviation were divided into 2 groups. Bilateral differences of minimum cross-sectional area, mean cross-sectional area, volume of subdivisions (nasopharynx, palatopharynx, glossopharynx, hypopharynx) were assessed paired t test. Stepwise linear regression analysis and Pearson correlation coefficients were computed between a significant pair of upper airway variables and a pair of mandibular deviation variables to examine the quantitative relationship between the upper airway asymmetry and mandibular deviation. The mean cross-sectional area and the volume of palatopharynx on the deviated side in mandibular deviated group was significantly smaller than non-deviated side. The asymmetry index of the palatopharyngeal volume showed significant correlations with CRA asymmetry (r = 0.49) and Ramus asymmetry (r = 0.54). However, in the glossopharyngeal and hypopharyngeal segment, the mandibular deviated group showed significant asymmetry, characterized by larger mean cross-sectional area and volume in deviated side. The asymmetry index of the glossopharyngeal volume and hypopharyngeal volume showed significant correlations with CRA asymmetry (r = 0.42), Me-s (r = 0.72) and Me-s (r = 0.67) respectively.

A retrospective cephalometric study on upper airway spaces in different facial types

Background

Craniofacial growth pattern has been correlated with variations in size of the upper airway spaces. The objective of this study was to evaluate the nasopharyngeal, oropharyngeal, and hypopharyngeal airway spaces variations according to the craniofacial growth pattern, by comparing brachyfacial, mesofacial, and dolichofacial in Angle Class I individuals.

Methods

To measure the spaces, 45 lateral teleradiographs were used and divided into 3 groups per the craniofacial growth pattern, determined by the Tweed cephalometry angular measurements: FMA and Y-axis. To evaluate the airways, sleep apnea cephalometry was used, containing 28 points that compose 14 factors. Three groups were compared relative to each of the 14 sleep apnea cephalometry measurements. Adherence test to the normal curve was performed. For the non-normally distributed data—measurement of the inferior pharyngeal space—the Kruskal-Wallis test was used for comparison between the groups. For the remaining data, the distribution was normal and ANOVA test was used.

Results

Statistically significant difference was verified among the groups for the measurement of the median posterior-palatal space, with the difference being pointed out by the post hoc test between the brachyfacial and dolichofacial groups. For the other measurements, there was no statistically significant difference.

Conclusions

It could be concluded that there was difference in the median posterior-palatal space measurement, in the oropharynx region, which was reduced for individuals with a dolichofacial pattern.

Three-Dimensional Evaluation of the Upper Airway in Children of Skeletal Class III

The present study was aimed to investigate the relationship of the upper airway size and craniofacial structures in 3 dimensions in growing children of skeletal Class III. Forty-seven children (19 boys and 28 girls, 9.6 ± 1.3 years of age, range 8.0-12.4 years) were selected. Twenty-three children with normal vertical development were divided into groups of insufficient maxilla and overdeveloped mandible for the airway comparison between different sagittal skeletal patterns. Thirty-two children with the same sagittal development were divided into groups of low angle, normal angle, and high angle for the comparison between different vertical skeletal developments. The upper airway and craniofacial structures were measured in cone beam computed tomography images using DOLPHIN 11.7 software. Mann-Whitney U test and Kruskal-Wallis test were used to analyze the airway differences between groups. Spearman correlated analysis was done between the upper airway size and the craniofacial pattern in the transverse dimension. The results showed that the nasopharynx was the only affected airway part between groups of insufficient maxilla and overdeveloped mandible (P <0.05). The high angle group showed smaller upper airway compared with the groups of normal angle and low angle (P <0.05). The skeletal transverse dimension was correlated with the height of velopharynx, hypopharynx, and total airway with small gender differences.

Craniofacial skeletal pattern: is it really correlated with the degree of adenoid obstruction?

OBJECTIVE

The aim of this study was to compare the cephalometric pattern of children with and without adenoid obstruction.

METHODS

The sample comprised 100 children aged between four and 14 years old, both males and females, subjected to cephalometric examination for sagittal and vertical skeletal analysis. The sample also underwent nasofiberendoscopic examination intended to objectively assess the degree of adenoid obstruction.

RESULTS

The individuals presented tendencies towards vertical craniofacial growth, convex profile and mandibular retrusion. However, there were no differences between obstructive and non-obstructive patients concerning all cephalometric variables. Correlations between skeletal parameters and the percentage of adenoid obstruction were either low or not significant.

CONCLUSIONS

Results suggest that specific craniofacial patterns, such as Class II and hyperdivergency, might not be associated with adenoid hypertrophy.

Cephalometrics of Pharyngeal Airway Space in Lebanese Adults

Purpose. The upper airway space is significant in orthodontic diagnosis and treatment planning. The objectives of this study are to assess the dimensions of soft tissue elements of the upper pharyngeal space and evaluate potential correlations with modifying variables such as gender, skeletal class, and anthropometric parameters. Materials and Methods. Lateral cephalograms were obtained from 117 healthy young adult Lebanese subjects. Nineteen cephalometric linear/angular measurements of the nasopharynx, oropharynx, and hypopharynx were recorded. Anthropometric parameters including body mass index and neck circumference were measured. Results. Significant differences were demonstrated for 12 out of the 19 parameters considered between genders. Uvula and tongue dimensions and the distances between epiglottis-posterior pharyngeal wall and epiglottis-posterior nasal spine were significantly larger in males. The anteroposterior inclination of the uvula and the distances between the uvula and posterior pharyngeal wall were significantly greater in females. No significant differences were found between skeletal classes relative to most of the variables. Body mass index and neck circumference were positively correlated with the dimensions of tongue and uvula. Conclusions. Sexual dimorphism relative to some cephalometric variables and anthropometric parameters may account partly for larger oronasopharyngeal spaces in females. Anthropometric data need to be accounted for in population-related comparisons.

Effect of retraction of anterior teeth on pharyngeal airway and hyoid bone position in Class I bimaxillary dentoalveolar protrusion

BACKGROUND

To test the hypothesis that the retraction of anterior teeth has no effect on the dimensions of pharyngeal airway and to evaluate the retraction of anterior teeth on each parameter of pharyngeal airway.

METHODS

Twenty-two adult patients of Class I bimaxillary protrusion requiring first premolar extractions with maximum anchorage requirements were selected. The pharyngeal airway and dentofacial parameters of the patients were compared using pre- and post-treatment lateral cephalograms with the help of Student's paired t-test (P < 0.05). The relationship between airway size and dentofacial parameters was also evaluated using Pearson correlation coefficient.

RESULTS

The upper and lower lips were retracted by 2.25 and 5.4 mm after retraction of the incisors. The tips of upper and lower incisors were retracted by 7.75 and 7.15 mm, respectively. There was a statistically significant decrease in SPP-SPPW (P < 0.05), U-MPW (P < 0.001), TB-TPPW (P < 0.001), and change in HRGN (P < 0.01). A significant correlation was observed between the amount of retraction of lower incisor and decrease in the pharyngeal airway posterior to soft palate (r = 0.102), tongue (r = 0.322), and change in HRGN (r = 0.265).

CONCLUSIONS

The size of the pharyngeal (velopharyngeal and glossopharyngeal) airway reduced and hyoid bone position changed after retraction of the incisors in extraction space in bimaxillary protrusive adult patients.

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.

Evaluation of Pharyngeal Space in Different Combinations of Class II Skeletal Malocclusion

Objectives:

The study was aimed to evaluate the pharyngeal airway linear measurements of untreated skeletal class II subjects with normal facial vertical pattern in prognathic maxilla with orthognathic mandible and orthognathic maxilla with retrognathic mandible.

Materials and method:

the sample comprised of lateral Cephalograms of two groups (30 each) of class II malocclusion variants. Group 1 comprised of class II malocclusion with prognathic maxilla and orthognathic mandible, whereas group 2 comprised of class II malocclusion with orthognathic maxilla and retrognathic mandible. Each group was traced for the linear measurements of the pharyngeal airway like the oropharynx, nasopharynx and soft palate. The obtained data was subjected to independent t test and the Mann Whitney test to check the difference between the two groups and within the groups respectively.

Results:

there was significant difference between all the linear measurements at the soft palate region and the distance between the tip of soft palate to its counter point on the pharyngeal wall in oropharynx region (p-ppm).

Conclusion:

the pharyngeal airway for class II malocclusion with various combination in an average growth pattern adult showed significant difference. The present results suggested, that the pharyngeal airway space might be the etiological factor for different sagittal growth pattern of the jaws and probable usage of different growth modification appliance can influence the pharyngeal airway.

Airway in Class I and Class II skeletal pattern: A computed tomography study

BACKGROUND AND OBJECTIVES

A normal airway is required for the normal growth of the craniofacial structures. The present study was designed to evaluate and compare the airway in Class I and Class II skeletal pattern and to see if there is any association between the airway and maxillomandibular relationship.

MATERIALS AND METHODS

Peripheral nervous system computed tomography scans of 30 patients were divided into two groups as Class I (ANB ≤ 4.5°), Class II (ANB ≥ 4.5°). The Dolphin three-dimensional version 11 was used to assess the airway.

STATISTICAL ANALYSIS

Correlations between the variables were tested with the Pearson correlation coefficient. Independent sample t-test was performed to compare the averages between the two groups. P < 0.05 was considered as statistically significant.

RESULTS

The ANB angle was negatively correlated with all the airway parameters. The airway area and volume was significantly reduced in Class II subjects compared to Class I.

CONCLUSION

The results suggest a strong association between the airway and skeletal pattern showing a reduced airway in Class II patients with a high ANB angle.

Effects of reverse headgear on pharyngeal airway in patients with different vertical craniofacial features

The aim of this study was to investigate the effects of reverse headgear (RH) on pharyngeal airway morphology in two groups of Class III patients with different vertical craniofacial features in comparison with an untreated Class III group. Seventeen subjects (9 males, 8 females; mean age 11.3 ± 0.98 years) with optimum vertical growth and 17 subjects (10 males, 7 females, mean age 11.5 ± 1.1 years) with a vertical growth pattern treated with a removable intra-oral appliance and a Delaire type facemask were included. An untreated Class III control group of 11 subjects (8 males, 3 females, mean age 9.1 ± 1.1 years) was included to compare the treated groups. The paired t-test for intragroup and one-way ANOVA for intergroup comparisons were performed. The relationships between changes in the craniofacial morphology and airway were assessed by Spearman correlation analysis. The airway dimensions at the adenoid side and soft palate were increased in the treatment groups compared to the control group (p < 0.05). The nasopharyngeal area demonstrated a significant difference in normodivergent and control subjects (p < 0.05). No significant difference was found in the airway morphology due to different vertical features. The effect of RH treatment on the sagittal airway dimensions revealed no significant difference between different vertical craniofacial features in the short term.

Assessment of the soft tissue thickness at the lower anterior face in adult patients with different skeletal vertical patterns using cone-beam computed tomography

OBJECTIVE

To evaluate and compare the soft tissue thickness values at the lower anterior face among adult patients with different vertical growth patterns using cone-beam computed tomography.

MATERIAL AND METHODS

The study sample consisted of 105 adult patients (54 women and 51 men) with a normal sagittal skeletal pattern divided into three groups according to the vertical growth pattern: high-angle (women/men, 22/13; mean age, 24.54 ± 4.45 years), low-angle (women/men, 14/21; mean age, 24.62 ± 5.08 years), and normal-angle (women/men, 18/17; mean age, 24.22 ± 5.40 years) groups. The soft tissue thickness measurements at the lower anterior face in each group were done and analyzed using the one-way analysis of variance and Tukey tests.

RESULTS

Soft tissue thickness values were the lowest in the high-angle group for both women and men. For women, the thickness values at the labrale superius, labrale inferius, and pogonion were found to be statistically significantly smaller in the high-angle group (11.49 ± 1.05 mm, 12.70 ± 1.92 mm, and 11.64 ± 2.65 mm, respectively) compared with the values in the normal-angle group (13.31 ± 2.01 mm, 15.08 ± 1.94 mm, and 14.69 ± 3.08 mm, respectively) (P < .05, P < .05, and P < .01, respectively). For men, however, no statistically significant differences were found among the vertical growth patterns (P > .05).

CONCLUSION

Women had statistically significantly thinner thickness at the labrale superius, labrale inferius, and pogonion in the high-angle group compared with the normal-angle group.

Cephalometric study of the upper airways and dentoalveolar height in open bite patients

Open bite is related to various etiological factors and, in many cases, is difficult to diagnose. The present study is aimed at evaluating, through cephalometric analysis, the dimensions of the upper airways and dentoalveolar heights in open bite (OB) patients versus normal overbite patients. The relationship between the width of the upper airways and the lack of overbite is also studied, in order to differentiate between dental open bite (DOB) and skeletal open bite (SOB).

MATERIALS AND METHODS

Eighty X-rays were selected from files of orthodontic patients to form the control sample (n=40) and open bite sample (n=40). Dimensions of the upper airways and dentoalveolar heights were measured in both samples, using 16 linear measurements, two angle values and one ratio.

RESULTS

In OB patients, anteroposterior narrowing of the upper airways, mainly in the nasopharynx and oropharynx, was observed, together with forward displacement of the hyoid bone and increased maxillary and mandibular dentoalveolar heights, and anterior facial height. In SOB, the overbite was more negative and facial growth was more clockwise-oriented than in DOB. Greater narrowing of the airways in the anteroposterior orientation was also noted. In DOB, there was evidence of muscular adaptation, as shown by increased values of the hyoid bone displacement to a more anterior and lower position, and increased values of the vertical dimensions of the airways. An increase in posterior facial height was also observed allowing anterior rotation of the mandible.

CONCLUSION

The results suggest that the airway's dimensions reflect a tendency to open bite. The variable vertical airway length (Val) and the position of the hyoid bone allow the adaptive potential of these individuals to be determined and make the treatment of open bites more predictable.

The influence of craniofacial morphology on the upper airway dimensions

Objective: 

To evaluate the influence of craniofacial morphology on the upper airway dimensions in healthy adult subjects.

Materials and Methods: 

The records of 276 healthy 17- to 27-year-old patients were extracted from the cone-beam computed tomography image database of the Institute of Stomatology, Riga Stradins University. Dolphin 11.7 software was used to evaluate craniofacial anatomy and semiautomatic segmentation of the upper airway. Measurements of oropharyngeal airway volume (OPV), minimal cross-sectional area (CSAmin), and nasopharyngeal airway volume (NPV) were obtained. The presence of adenoid tissues was recorded. Associations between variables were analyzed by Spearman's correlation coefficients, and multivariate linear regression analysis was used to identify factors that had a possible influence on upper airway dimensions.

Results: 

The following factors were identified as influencing the variability of NPV (23%): SNA angle, gender, and presence of adenoids. Statistically significant, although weak, correlations were found between SNB angle and OPV (r  =  0.144, P &lt; .05) and CSAmin (r  =  0.182, P &lt; .01).

Conclusion: 

The results suggest that craniofacial morphology alone does not have a significant influence on upper airway dimensions.

Comparison of pharyngeal airway volume among different vertical skeletal patterns: a cone-beam computed tomography study

OBJECTIVE

To test the null hypothesis that there are no significant differences in pharyngeal airway volumes among adult patients with different vertical skeletal patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT).

MATERIAL AND METHODS

The study sample consisted of 100 adult patients (45 men and 55 women; mean age  =  24.0 ± 5.3 years) with a normal sagittal skeletal pattern divided into three groups according to the vertical skeletal patterns: high angle (32 patients: 15 women and 17 men), low angle (34 patients: 14 women and 20 men), and normal angle (34 patients: 16 women and 18 men) groups. Nasopharyngeal, oropharyngeal, and total airway volumes of patients in all vertical groups were calculated. Group differences were analyzed using one-way analysis of variance and post hoc Tukey tests.

RESULTS

Nasopharyngeal airway volume in the high-angle group (mean  =  6067.9 ± 1693.9 mm(3)) was significantly lower than that of the low- and normal-angle groups (P < .01). Oropharyngeal airway volume was highest in the low-angle group (mean  =  15,957.6 ± 6817.2 mm(3)) and significantly decreased in the control (mean  =  11,826.1 ± 4831.9 mm(3); P  =  .008) and high angle (mean  =  10,869.1 ± 4084.1 mm(3); P  =  .001) groups. Total airway volume was highest in the low-angle group (mean  =  24,261.6 ± 8470.1 mm(3)) and lowest in the high-angle group (mean  =  16,937.0 ± 5027.4 mm(3); P < .001).

CONCLUSION

The null hypothesis was rejected. Significant differences were found in pharyngeal airway volumes among different skeletal vertical patterns.

Effects of first premolar extraction on airway dimensions in young adolescents: A retrospective cephalometric appraisal

OBJECTIVE

To evaluate the upper airway dimensions in adolescents treated for bimaxillary proclination with first premolar extraction.

MATERIALS AND METHODS

A retrospective cephalometric evaluation was carried out on the available pre and post orthodontic treatment records of 150 patients (12-18 years of age) who had bimaxillary proclination and were treated with fixed orthodontic therapy. Cephalometric landmarks for sagittal airway measurements and hyoid bone were identified; linear and angular measurements were obtained. Descriptive statistics using paired t-test was used to assess changes in pre and post treatment values and Pearson's correlation coefficient was calculated to evaluate the reliability of observations. The method error calculations were performed using the Dahlberg formula.

RESULTS

It was observed that the mean values of nasopharyngeal dimension and Total Airway Length (TAL) showed no statistically significant difference in pre and post treatment groups. All other airway and hyoid parameters showed statistically significant difference. Pearson's correlation coefficient showed statistically significant correlations in all the airway and hyoid parameters.

CONCLUSIONS

In the present study, the nasopharyngeal dimension and TAL were not found to be directly affected by the retraction of anterior teeth, This can be attributed to the fact that nasopharyngeal dimension and TAL are not under direct influence of tongue position. The other findings also indicated direct correlation of tongue position to oropharynx and hypopharynx. Consequently, we emphasize clinically relevant anatomic risk factors that should be given prime importance and serious consideration on the decision whether to extract or not in growing patients.