Two-dimensional lateral cephalometric evaluation of varying types of Class II subgroups on posterior airway space in postadolescent girls: a pilot study

Evaluation of the influence of hyoid bone position, volume, and types on pharyngeal airway volume and cephalometric measurements

OBJECTIVES

We aimed to explore the position, morphological, and morphometric properties of the hyoid bone (HB) and to investigate the effect of HB on the pharyngeal airway (PA) volume and cephalometric measurements.

METHODS

A total of 305 patients with CT images were included in the study. DICOM images were transferred to the InVivoDental three-dimensional imaging software. The position of the HB was determined based on the cervical vertebra level and in volume render tab, the bone was classified into six types after all structures around the HB were removed. Also, final bone volume was recorded. In the same tab, the pharyngeal airway volume was divided and measured in three groups (nasopharynx-oropharynx-hypopharynx). The linear and angular measurements were performed on the 3D cephalometric analysis tab.

RESULTS

HB was most commonly located in C3 vertebra level (80.3%). While B-type was found to be the most frequent (34%), V-type was the least frequent (8%). The volume of the HB was found to be significantly higher in male (3205 mm3) than female (2606 mm3) patients. Also, it was significantly higher in the C4 vertebra group. The vertical height of the face was positively correlated with the HB volume, C4 level position, and increased oro-nasopharyngeal airway volume.

CONCLUSION

The volume of the HB is found to differ significantly between genders and can potentially serve as a valuable diagnostic tool for understanding respiratory disorders. Its morphometric features are associated with increased face height and airway volume; however, are not related with the skeletal malocclusion classes.

The effect of orthodontic vertical control on the changes in the upper airway size and tongue and hyoid position in adult patients with hyperdivergent skeletal class II

BACKGROUND

At present, there are still controversies about the influence of orthodontic treatment on the size of upper airway and the position of hyoid bone. We investigated the effect of orthodontic vertical control therapy on the size of the upper airway and position of the tongue and hyoid bone in adult patients with hyperdivergent skeletal Class II.

METHODS

Overall, 15 adults with hyperdivergent skeletal Class II and normal occlusion, respectively, were selected as the experimental and control groups. The angle and line of the craniofacial structure, upper airway, hyoid bone position and three-dimensional (3D) upper airway indexes were measured using the Uceph 4.2.1 standard version and Mimics 21.0 software, respectively. The paired t-test, Wilcoxon symbol rank test, t-test of two independent samples, two independent sample nonparametric tests, Mann-Whitney U test, Pearson correlation analysis, the Univariate linear regression analysis and Multiple linear regression analysis were performed.

RESULTS

After treatment, the S-Go/N-Me (%) and the MP-SN and XiPm-SN angles were significantly different (P < 0.01). The U-MPW and PAS significantly increased (P < 0.05), sagittal diameter L₂ increased significantly, and transverse diameter L₂ decreased significantly (P < 0.01). Although no significant correlation was observed between the vertical change in the jaw and that in U-MPW and PAS, the sagittal diameter L₂ showed a significant correlation (P < 0.05). The Multiple linear regression analysis showed that there was a significant negative correlation between the variables MP-SN and sagittal diameter L₂ and positive correlation between S-Go/N-Me(%) and H-MP (P < 0.05). Furthermore, significant differences between the Hv (P < 0.01) and sagittal diameter L₁(P < 0.05) were observed before and after treatment.

CONCLUSIONS

After the orthodontic vertical control therapy in patients with hyperdivergent skeletal Class II, the upper airway only underwent adaptive changes during treatment without substantial size changes, the position of tongue body and hyoid bone did not change significantly. Furthermore, compared with normal occlusion, the velopharyngeal segment airway of patients with hyperdivergent skeletal Class II remains narrow and long after treatment.

Treatment of Dental Class-II, Division 2 Malocclusion Associated with a Deep Anterior Overbite: A Case Report Orthodontic Camouflage

AIM

This study sought to correct the assessment of orthodontic camouflage treatment to provide a harmonized soft-tissue profile, consistent occlusion, and a pleasant smile.

BACKGROUND

Class-II, division 2 malocclusions can be treated through dental compensation and growth modification methods instead of surgical-orthodontic treatment, which can be determined by the growth and age of the patient.

CASE DESCRIPTION

This case report was of a 14-year-old Chinese female whose chief complaint was crowding of anterior teeth and required treatment for the same. On necessary clinical and radiographical examination, diagnosis of convex facial profile with class-II, division 2 malocclusion was arrived and hence treated with orthodontic camouflage. On treatment completion of 33 months, cephalometric assessment revealed that the anterior maxillary teeth had been successfully intruded and substantially distalized, with a slight counterclockwise rotation of the mandible. The treatment results and profile changes were demonstrated with good patient cooperation.

CONCLUSION

Using a utility arch with orthodontic camouflage treatment can help to reinforce molar anchoring and improve a deep bite in the maxillary dentitions. The patient was treated with the devised treatment plan and acceptable results were obtained with patient satisfaction as recorded after 1 year of follow-up.

CLINICAL SIGNIFICANCE

To correct a maxillomandibular discrepancy, an orthodontist may conduct a process known as camouflage therapy without necessity of surgery. However, patient selection forms a crucial role, and hence systematic arrival of the diagnosis and treatment protocol is a pivotal factor.

Relationship between craniofacial and dental arch morphology with pharyngeal airway space in adolescents

PURPOSE

The aim of the study was to investigate a possible relationship between pharyngeal airway space, craniofacial variables, and dental arch form in adolescents grouped by sex.

METHODS

This cross-sectional study included 108 adolescents aged between 12 and 17 years. Lateral cephalometric radiographs were used to analyze sagittal craniofacial variables and the pharyngeal airway space. For evaluation of the dental arch form, we used plaster models. Statistical analysis included Student's t‑test and Pearson's correlation coefficient (r).

RESULTS

Maxillary length was directly proportional to upper nasopharyngeal airway dimensions in males (r = 0.312, p = 0.021) and females (r = 0.310, p = 0.022). In the female group, upper oropharyngeal measurements showed an inverse correlation with a labial inclination of the upper incisors (r = -0.415, p = 0.001), protrusion of the upper incisors (r = -0.364, p = 0.006), and soft palate thickness (r = -0.27, p = 0.043). In the male group, upper nasopharynx measurements showed an inverse correlation with soft palate thickness (r = -0.277, p = 0.042). The upper arch form appeared to be related to oropharyngeal measurements in females, while the lower arch form was related to oropharyngeal dimensions in males.

CONCLUSION

The findings suggest that there are sex-dependent correlations of the nasopharyngeal and oropharyngeal airway space with the sagittal craniofacial morphology and the transversal dental arch form.

Longitudinal Morphological Changes in the Adenoids and Tonsils in Japanese School Children

The adenoid (Ad) and tonsil (Ts), located in the upper airway, play an important role in immunological protection. These lymphoid tissues grow rapidly, reach a peak of growth at the age of 6-8 years, and decrease in their size thereafter. However, little information is available on the longitudinal growth patterns of Ad and Ts in the general population. This study aimed to evaluate the individual growth of Ad and Ts during childhood using lateral cephalograms taken longitudinally from the same individuals at the ages of 8-12 years. Our results showed that the cross-sectional areas of the Ad, nasopharynx (Np), and oropharynx (Op) significantly increased with age while small changes in the size of Ts were present throughout the study period. In addition, the values of Ad/Np and Ts/Op decreased significantly with age in the elementary school. Furthermore, there was a strong and significant correlation between the Ad/Np ratio and upper airway resistance, indicating the narrowest distance in the upper airway. In conclusion, the airway occupation in Np and Op increased with age due to the increase in the sizes of Np and Op but not the decrease in the sizes of Ad and Ts.

Effects of miniscrew-assisted orthodontic treatment with premolar extractions on upper airway dimensions in adult patients with Class II high-angle malocclusion

INTRODUCTION

The primary aim of this study was to investigate the change in upper airway dimensions and in mandibular position after miniscrew-assisted treatment with premolar extractions in adult patients with Class II high-angle malocclusion. The secondary aim was to determine the correlation between changes in upper airway dimensions and changes in mandibular position in these patients.

METHODS

Eighteen adult patients with Class II high-angle malocclusion (mean ± standard deviation age = 21.2 ± 2.9 years) were selected retrospectively. All patients underwent 4 premolar extractions, and 2 miniscrews were implanted in the maxilla to intrude molar height. Cone beam computed tomography images were taken pretreatment and posttreatment for every patient. The primary outcome variable for the upper airway was the minimal cross-sectional area of the upper airway (CSA_min), and the primary outcome variables for the mandible were mandibular rotation (Mp-SN angle), mandibular horizontal position (SNB angle), and mandibular vertical position (ANS-Me distance).

RESULTS

The CSA_min significantly increased by 47.2 mm² (t = -2.26, P = 0.04) after orthodontic treatment. The mandible significantly rotated counterclockwise by 0.9° (t = 2.20, P = 0.04) after treatment, which consisted of forward movement of 1.2° (t = -4.30, P = 0.00) and upward movement of 1.3 mm (Z = -1.98, P = 0.05). Furthermore, the change of the CSA_min showed a significant correlation with the change of the ANS-Me (P = 0.01).

CONCLUSIONS

By using miniscrews to intrude maxillary molars, orthodontic premolar extraction treatment results in mandibular counterclockwise rotation, and upper airway dimensions increase in Class II high-angle young adult patients. The increase of the upper airway dimensions significantly correlates to the upward movement of the mandible.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

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.

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.

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.

A three dimensional study of upper airway in adult skeletal Class II patients with different vertical growth patterns

OBJECTIVE

The study was performed to compare the 3D pharyngeal airway dimensions in adult skeletal Class II patients with different vertical growth patterns (low, normal, and high angle) and to investigate whether the upper airway dimensions of untreated skeletal Class II adults were affected by vertical skeletal variables.

METHODS

Cone-beam computed tomography (CBCT) records of 64 untreated adult skeletal Class II patients (34 male and 30 female) were collected to evaluate the pharyngeal airway dimensions. Subjects were divided into three subgroups according to the GoGn-SN angle (low angle, normal angle or high angle). All subgroups were matched for sex. ANOVA and SNK-q tests were used to identify differences within and among groups (p<0.05). Coefficient of product-moment correlation (Pearson correlation coefficient) was used to analyze the association between pharyngeal airway dimensions and vertical growth patterns.

RESULTS

The results showed that pharyngeal airway measurements were statistically significantly less (p<0.05) in high angle group as compared to normal angle or low angle group.

CONCLUSIONS

Adult skeletal Class II subjects with vertical growth patterns have significantly narrower pharyngeal airways than those with normal or horizontal growth patterns, confirming an association between pharyngeal airway measurements and a vertical skeletal pattern.