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

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.

Screening for Obstructive Sleep Apnea and Associated Risk Factors in Adolescents and Adults With Isolated Robin Sequence

OBJECTIVE

To investigate the subjective risk for obstructive sleep apnea (OSA) in adolescents and young adults with isolated Robin sequence (IRS). Additionally, to investigate the association of OSA risk with respiratory signs/symptoms, and retrognathia.

DESIGN

Prospective, observational, and cross-sectional study.

SETTING

Tertiary reference hospital for the rehabilitation of craniofacial anomalies.

PARTICIPANTS

Adolescents and adults (n = 30) with IRS were clinically evaluated and screened through the Berlin Questionnaire (BQ) and Respiratory Symptoms Questionnaire. The maxillomandibular relationship was assessed on lateral cephalograms of those that reached skeletal maturity (n = 13). Polysomnography (PSG) was performed in a subgroup of 4 individuals.

RESULTS

The mean age of the sample was 18.2 (±3.4) years, 17 (56.7%) were adolescents (14-19 years), and 16 were (53.3%) female, all presented a repaired cleft palate.

CLINICAL PARAMETERS

Systemic arterial pressure (118.0 ± 4.1/76.3 ± 4.9 mmHg), body mass index (BMI) (20.9 ± 2.8 kg/m2), neck (33.2 ± 2.3 cm), and waist circumferences (72.0 ± 5.8 cm) were within normal ranges. A skeletal class I pattern was observed in 61.5% of the participants while a class II was seen in 15.4% of them. A high risk for OSA was detected in 16.7%, and it was associated with nasal obstruction, snoring and drowsiness, and a skeletal class II pattern (P ≤ .05). One patient presented with mild OSA (apnea-hypopnea index [AHI] = 10.1 events/hour) at the PSG exam.

CONCLUSIONS

A high risk for OSA can be observed with a moderate frequency among adolescents and young adults with IRS, especially among those who are concurrently suffering from nasal obstruction, snoring and retrognathia.

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.

Pharyngeal airway dimensions in Iranian female young adults with different skeletal patterns using cone-beam computed tomography

OBJECTIVES

To assess the oropharyngeal airway in Iranian female young adults with different skeletal patterns using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

This descriptive, cross-sectional study evaluated 105 CBCT scans of female patients between 18 and 35 years retrieved from the archives of a radiology clinic. The images were evaluated in axial, sagittal, and frontal sections. In the axial plane, the maximum and minimum cross-sectional area (CSA) of the airways at the oropharynx, minimum width (anteroposteriorly), and minimum depth (laterally) were measured using Mimics Medical software. The oropharyngeal volume was measured by NemoFAB software. The values were compared among the groups with different sagittal, vertical, and transverse patterns. The correlation of indices with airway measurements was analyzed using Monte Carlo Chi-square and Pearson's correlation coefficient.

RESULTS

No significant difference was noted in oropharyngeal airway dimensions and volume among cases with different skeletal sagittal, vertical, and transverse patterns (P > 0.05) except for class III patients with normal transverse pattern in whom maximum CSA in low-angle group was larger than that in normal-angle group (P < 0.05) and class I normal-angle patients in whom maximum CSA in transverse normal group was smaller than that in constriction group (P < 0.05).

CONCLUSIONS

Oropharyngeal dimensions were not significantly different in Iranian female young adults with different skeletal patterns.

Artificial Intelligence as an Aid in CBCT Airway Analysis: A Systematic Review

BACKGROUND

The use of artificial intelligence (AI) in health sciences is becoming increasingly popular among doctors nowadays. This study evaluated the literature regarding the use of AI for CBCT airway analysis. To our knowledge, this is the first systematic review that examines the performance of artificial intelligence in CBCT airway analysis.

METHODS

Electronic databases and the reference lists of the relevant research papers were searched for published and unpublished literature. Study selection, data extraction, and risk of bias evaluation were all carried out independently and twice. Finally, five articles were chosen.

RESULTS

The results suggested a high correlation between the automatic and manual airway measurements indicating that the airway measurements may be automatically and accurately calculated from CBCT images.

CONCLUSIONS

According to the present literature, automatic airway segmentation can be used for clinical purposes. The main key findings of this systematic review are that the automatic airway segmentation is accurate in the measurement of the airway and, at the same time, appears to be fast and easy to use. However, the present literature is really limited, and more studies in the future providing high-quality evidence are needed.

Comparison of Nasopharyngeal Airway Volume in Cleft Lip and Palate Patients With Normal Individuals Using Cone Beam Computed Tomography

This study aimed to compare nasopharyngeal airway volume in cleft lip and palate patients with normal individuals using Cone Beam Computed Tomography (CBCT). In this cross-sectional study, 40 CBCT scans of 9 to 12-years-old patients were enrolled and divided into 3 groups: normal individuals (n=16), unilateral cleft lip and palate (UCLP, n=14) and bilateral cleft lip and palate patients (BCLP, n=10). Superior and middle pharyngeal airway volumes and nasal width were measured and compared between 3 groups. ANOVA and χ 2 tests were used for statistical comparison. P <0.05 was considered significant. Superior airway volume was not significantly different between the 3 groups ( P =0.36). However, there was a significant difference between the 3 groups regarding middle pharyngeal volume ( P =0.49) and nasal width ( P =0.021). There was not a significant difference in the upper and middle pharyngeal volume and also nasal width between the 2 sexes. Considering different dimensions of evaluation of the pharyngeal airway volume of cleft lip and palate patients, the evaluation of airway volume is essential during orthodontic or orthognathic surgical treatments that expand or protect the maxilla.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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&lt;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&lt;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.

Oropharynx and hyoid bone changes in female extraction patients with distinct sagittal and vertical skeletal patterns: a retrospective study

Background

Previous studies have reported inconsistent effects of premolar extraction on the oropharynx and hyoid bones. Currently, no strong evidence is available regarding the effect of extraction on upper airway size. Hence, the aim of this study was to analyse the effects of first premolar extraction on the oropharynx and hyoid bone positions in female adult patients, and further explored differences in oropharynx and hyoid bone changes among skeletal patterns.

Methods

The study population included 40 female adult patients who did not undergo extraction and 120 female adult patients who underwent extraction of four premolars; the including patients had four distinct sagittal and vertical skeletal patterns. Cone-beam computed tomography was performed before (T0) and after (T1) orthodontic treatment. Eight oropharynx variables and five hyoid bone variables were measured using Dolphin 3D Imaging software. Paired and independent t-tests were used to analyse measurements between timepoints and groups, respectively.

Results

The oropharynx volume increased significantly in the extraction group; changes did not differ significantly between extraction and non-extraction groups. Oropharynx variables did not differ significantly at T0 among the four skeletal pattern groups. After orthodontic extraction treatment, the oropharynx volume increased significantly in the class I-norm and class I-hyper subgroups, but not in the class II-norm and class II-hyper subgroups. Significant increases were observed in the oropharynx volume and most constricted axial area from T0 to T1 in the moderate retraction group, but not in the maximum retraction group. Extraction patients exhibited significant posterior movement of the hyoid, particularly among maximum retraction patients.

Conclusions

In female adult patients, first premolar extraction tends to increase the oropharynx size and cause posterior movement of the hyoid bone, particularly in skeletal class I patients. For skeletal class II and hyperdivergent patients with a narrow oropharynx, first premolar extraction does not negatively influence oropharynx size or hyoid bone position. The differences of oropharyngeal changes between moderate retraction patients and maximum retraction patients were not significant.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13005-022-00334-1.

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.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Relationship of the maxillary posterior teeth and maxillary sinus floor in different skeletal growth patterns: A cone-beam computed tomographic study of 1600 roots

Purpose

This study evaluated the distance from the posterior root apices to the maxillary sinus floor (MSF) and the frequency of roots touching or protruding through the MSF using cone-beam computed tomography (CBCT).

Materials and Methods

This study included 100 subjects divided into different vertical and anteroposterior skeletal growth patterns. On CBCT images, the distance from the posterior root apices to MSF was measured and the frequency of roots touching or protruding through the MSF was evaluated using NNT software (version 5.3.0.0; ImageWorks, Elmsford, NY, USA).

Results

No statistically significant differences were found in the distance from the posterior root apices to the MSF among vertical skeletal groups (P>0.05). The palatal roots of the first molar and the palatal, mesio-buccal and disto-buccal roots of the second molars had significantly less distance from MSF in skeletal class II than in class III (P<0.05). The high-angle group had the highest frequencies of roots touching or protruding into the maxillary sinus (49.8%); the lowest proportion of these roots was found in skeletal class III (28.3%) and the highest proportion in class II (50.3%). Males had shorter distances from the posterior root apices to the MSF and higher frequencies of roots protruding through or touching the MSF than females.

Conclusion

Anteroposterior skeletal growth patterns and sex affected the distances from the maxillary posterior roots to the MSF. The frequency of roots protruding into or touching the sinus was affected by both vertical and anteroposterior skeletal groups and sex. These findings have implications for dental practice.

Three-dimensional assessment of pharyngeal airway in individuals with myotonic dystrophy type 1

Background/aim

The objectives of this study were to assess pharyngeal airway volume (PAV) in patients with myotonic dystrophy type 1 (DM1) by cone-beam computerized tomography (CBCT) and to evaluate the impact of diaphragm thickness and pulmonary function tests on PAV.

Materials and methods

Thirty DM1 patients (10 female and 20 male; mean age 42.40 ± 12.07) were included in the study. Age and sex-matched thirty patients were participated as control group. In DM1 group pulmonary function tests (PFT) were performed. Independent t-test was used to compare PAV values of patients with DM1 and control group. The Mann–Whitney U test was used to compare the parameters according to sex ( p < 0.05). Pearson and Spearman correlation tests were used to evaluate the relationships between parameters of DM1 patients (p < 0.05). A multiple linear regression analysis was performed to explain the PAV with parameters that showed positive correlation with PAV.

Results

Age of onset and disease duration were 22.37 ± 8.45 and 20.03 ± 12.08, respectively, in patients with DM1. PAV values of control group were significantly lower than DM1 group ( p < 0.001). Forced expiratory volume in 1 s and forced volume vital capacity values were higher in males than females in DM1 group according to sex ( p < 0.001). PAV values were greater in male patients than females of the DM1 group ( p = 0.022). Diaphragm thickness in DM1 group after inspiration and expiration were 2.60 ± 0.65 and 1.94 ± 0.40, respectively. According to the regression analysis, DTai and FVC were significantly explained the PAV.

Conclusion

PAV was higher in DM1 group. There was a significant positive correlation between diaphragm thickness, pulmonary functions, and PAVs of DM1 patients. The amount of the PAV was mostly influenced by DTai and FVC. It is recommended to evaluate the PAV in patients with DM1 because of impaired respiratory functions and pharyngeal muscle involvement.

Relationship of skeletal malocclusion with eye and hair color in Turkish adolescent patients

Objectives:

The aim of this study was to establish whether a relationship exists between eye and hair color and orthodontic anomalies; an association has never been evaluated previously.

Materials and Methods:

The records of 406 adolescent patients to the Erciyes University Faculty of Dentistry for orthodontic treatment were included in this retrospective cohort study. Participants were divided into sagittal (Class I, Class II, and Class III) and vertical (low angle, normal angle, and high angle) skeletal malocclusion classes. Moreover, participants were also divided by their eye (brown, green, or blue) and hair (black, brown, or blonde) color. Collated data were statistically evaluated using the SPSS software by applying the one-way analysis of variance, Kruskal–Wallis, the Pearson Chi-square, and Fisher’s exact tests. Statistical significance was accepted at P < 0.05.

Results:

No statistically significant relationships were identified between sagittal and skeletal malocclusion and eye color (P > 0.05). However, the sella-nasion-b and CoGn parameters of brown-eyed individuals were significantly smaller than individuals with other eye colors (P < 0.05). Moreover, a statistically significant difference was established for the CoA, CoGn, and ANS-Me parameters between the different hair groups (P < 0.05). All three parameters were significantly lower in brown-haired individuals compared to individuals with black haired (P < 0.05).

Conclusion:

This study identified no significant association between the eye and hair color variable, with similarly formed craniofacial structures, and with the sagittal and vertical skeletal malocclusion. Therefore, any malocclusion estimation assumption formed based on either the hair or eye color of an individual will be incorrect.

Automatic segmentation of the pharyngeal airway space with convolutional neural network

OBJECTIVES

This study proposed and investigated the performance of a deep learning based three-dimensional (3D) convolutional neural network (CNN) model for automatic segmentation of the pharyngeal airway space (PAS).

METHODS

A dataset of 103 computed tomography (CT) and cone-beam CT (CBCT) scans was acquired from an orthognathic surgery patients database. The acquisition devices consisted of 1 CT (128-slice multi-slice spiral CT, Siemens Somatom Definition Flash, Siemens AG, Erlangen, Germany) and 2 CBCT devices (Promax 3D Max, Planmeca, Helsinki, Finland and Newtom VGi evo, Cefla, Imola, Italy) with different scanning parameters. A 3D CNN-based model (3D U-Net) was built for automatic segmentation of the PAS. The complete CT/CBCT dataset was split into three sets, training set (n = 48) for training the model based on the ground-truth observer-based manual segmentation, test set (n = 25) for getting the final performance of the model and validation set (n = 30) for evaluating the model's performance versus observer-based segmentation.

RESULTS

The CNN model was able to identify the segmented region with optimal precision (0.97±0.01) and recall (0.96±0.03). The maximal difference between the automatic segmentation and ground truth based on 95% hausdorff distance score was 0.98±0.74mm. The dice score of 0.97±0.02 confirmed the high similarity of the segmented region to the ground truth. The Intersection over union (IoU) metric was also found to be high (0.93±0.03). Based on the acquisition devices, Newtom VGi evo CBCT showed improved performance compared to the Promax 3D Max and CT device.

CONCLUSION

The proposed 3D U-Net model offered an accurate and time-efficient method for the segmentation of PAS from CT/CBCT images.

CLINICAL SIGNIFICANCE

The proposed method can allow clinicians to accurately and efficiently diagnose, plan treatment and follow-up patients with dento-skeletal deformities and obstructive sleep apnea which might influence the upper airway space, thereby further improving patient care.

Pharyngeal Airway Morphology in Skeletal Class III With Mandibular Asymmetry is Improved After Bimaxillary Orthognathic Surgery

PURPOSE

The relationship between pharyngeal airway morphology and jawbone movements in skeletal Class III patients with mandibular asymmetry after orthognathic surgery remains unclear. This study was to measure the changes in pharyngeal airway morphology in skeletal Class III patients with mandibular asymmetry after bimaxillary surgery and evaluate associations between changes in pharyngeal airway morphology and skeletal movements.

METHODS

In this retrospective cohort study, skeletal Class III patients who underwent bimaxillary surgery were enrolled. The predictor variable was facial symmetry status divided into 2 groups, asymmetric (Group A) and symmetric (Group B). The primary outcome variables were changes in airway parameters, including cross-sectional linear distances, cross-sectional area (CSA), minimum CSA (Min-CSA), and volume; and airway asymmetry index between the preoperative and 6-month postoperative imaging studies. Correlation analysis was performed between upper airway and skeletal changes.

RESULTS

Twenty-five patients were included in this study, with 15 patients in Group A (mean age: 23.00 years; BMI: 22.83) and 10 patients in Group B (mean age: 22.30 years; BMI: 22.48). Group A showed a higher asymmetry index than Group B at T0; however, no significant differences compared to Group B at T1. The airway volume was significantly decreased in the oropharynx in Group A at T1, whereas it showed no significant differences in Group B (P < .05). Lateral movement of B point and Menton showed positive correlations with changes in Min-CSA in the oropharynx and negative correlations with changes in airway asymmetry index (P < .05).

CONCLUSIONS

Pharyngeal airway exhibited an asymmetrical and constricted morphology in Group A before surgery. The airway morphology in Group A showed a tendency to adopt a symmetrical and less constricted shape after surgery. The airway space was reduced in the oropharynx in Group A after surgery. Surgical correction of mandibular asymmetry correlated with the improvement of pharyngeal airway morphology.

Comparison of cervical vertebral anomalies and sella turcica bridging in different growth stages with various vertical skeletal growth patterns

PURPOSE

To compare cervical vertebral anomalies and sella turcica bridging (STB) in different growth stages in orthodontic patients with different vertical skeletal growth patterns.

METHODS

Lateral cephalometric radiographs (LCR) of 270 patients in the preadolescent, adolescent, or postadolescent periods and having low angle [LA], normal angle [NA], or high-angle [HA] vertical skeletal growth patterns were evaluated retrospectively. STB was visualized using LCRs while evaluating the deficiency of ponticulus posticus (PP) and atlas posterior arch (PAA) associated with the atlas bone. The Pearson chi-square and Fisher's exact tests were used for categorical data and one-way ANOVA for numerical data.

RESULTS

The prevalence of fully calcified PP and STB increased from the preadolescent (PP, 10.0%; STB, 11.1%) to the postadolescent period (PP, 24.4; STB, 21.1%); they did not differ from vertical skeletal growth patterns (p > 0.05). The prevalence of PAA deficiency is significantly higher in individuals with LA (46.7%) than with other angles (NA, 27.8%; HA, 26.7%). The vertical skeletal growth pattern was significantly related to STB in the preadolescent period and PAA in the postadolescent period.

CONCLUSIONS

Different anomalies during different growth periods correlate with the vertical skeletal growth pattern. It will be useful to evaluate a different anomaly according to the relevant growth period.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

TRIAL REGISTRATION

ISRCTN69743543.

Comparison of dimensions and volume of upper airway before and after mini-implant assisted rapid maxillary expansion

OBJECTIVES

To evaluate changes in dimensions and volume of upper airway before and after mini-implant assisted rapid maxillary expansion (MARME) and observe correlations between changes of upper airway and vertical skeletal pattern in young adults.

MATERIALS AND METHODS

In this retrospective study, 22 patients (mean age, 22.6 ± 4.5 years; 4 male 18 female) with transverse discrepancy underwent MARME. Cone beam computed tomography was taken before and 3 months after expansion. Vertical and horizontal dimensions and volume of the nasal cavity, nasopharyngeal, retropalatal, retroglossal and hypopharyngeal airway were compared before and after MARME. Correlations between changed volume and dimensions were explored, as well as the vertical skeletal pattern.

RESULTS

Nasal osseous width, maxillary width, volume of the nasal cavity and nasopharynx increased significantly (P < .05). Enlarged nasopharyngeal volume correlated with increased nasal width at the PNS plane (P < .05). There were no correlations between expanded volume and maxillary width. No measurements except nasal cavity volume had a correlation with Sum angle. Increased maxillary width correlated negatively with hard palate thickness (P < .05).

CONCLUSIONS

(1) MARME caused an increase in volume of the nasal cavity and nasopharynx, with expansion of nasal osseous width and maxillary width. (2) Enlarged nasal width at the PNS plane contributed to the increase in nasopharynx volume. Enlarged maxillary width showed no direct relation with increased volume. (3) In this study, it was unclear about the association between changes of the upper airway and vertical skeletal pattern because of complex structures. (4) Palate thickness affected skeletal expansion of the maxilla in MARME.

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.

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.

Evaluation of upper airway volume and craniofacial volumetric structures in obstructive sleep apnoea adults: A descriptive CBCT study

OBJECTIVE

The aim of this investigation was to assess, with a descriptive three-dimensional evaluation, the volume of upper airway (UAWV) and the volume of craniofacial structures in adult patients suffering from obstructive sleep apnoea (OSA) and compare them to the corresponding findings in adults with no sleep disorders.

MATERIALS AND METHODS

The sample consisted of 54 adult males, 27 suffering from OSA diagnosed by means of the Apnoea Hypopnea Index and 27 with no history of sleep disorders. All subjects had a cone beam computerized tomography scan performed with the same head position. UAWV was assessed with the Amira® software, and craniofacial volumes by means of a specially developed data-processing program, which allowed the construction of tetrahedrons using anatomical landmarks. Assessed volumes were naso-maxillary, cranium upper anterior, oral cavity, post-oral cavity, hyoid to mandible, and post-hyoid. SPSS (version 19.0) was used for the statistical analysis. The Levene's test for Equality of Variance, the t-test for Equality of Means and the Mann-Whitney test were used to evaluate the variables. The level of significance was set at P ≤ 0.05.

RESULTS

The mean value of UAWV was smaller in the OSA group. The post-hyoid volume, the calculated posterior volume, and the ratio of posterior to total volume showed differences between the groups.

CONCLUSIONS

Craniofacial structures did not show significant differences between the groups, but in the OSA group the posterior space released for upper airway was significantly bigger and UAWV was significantly smaller.

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.

Comparison of pharyngeal airway volume in different skeletal facial patterns using cone beam computed tomography

Background

This study aimed to compare the pharyngeal airway volume in class I,II and III skeletal malocclusion patients using cone beam computed tomography (CBCT).

Material and Methods

This retrospective, cross sectional study was conducted on lateral cephalograms of 71 patients derived from their CBCT scans. Using the ANB angle, the patients were divided into class I,II and III malocclusion. Two observers used Dolphin 3D software to calculate the pharyngeal airway volume, airway area, minimum axial area, minimum area location, airway length and morphology. Data were analyzed using one-way ANOVA, Kruskal-Wallis test, Tukey’s test, Spearman’s correlation coefficient and multiple regression analysis.

Results

The three skeletal classes were significantly different in airway volume, minimum axial area, mean airway area and airway morphology (P<0.05). Significant differences were found in airway volume and mean airway area between class II and III patients (P<0.05). The minimum axial area and airway morphology in class III patients were greater than those in class I and II patients (P<0.05). Every one unit increase in the ANB angle decreased the airway volume by 0.261 units. The effect of ANB angle on airway volume was statistically significant and it was shown that one unit increase in the angle decreased the airway volume by 453.509 units.

Conclusions

A significant correlation exists between the skeletal facial pattern and upper airway dimensions. In our study, the total airway volume and the mean airway area of class III patients were larger than those in class II patients.

Key words:Cone-Beam computed tomography, malocclusion, pharyngeal airway volume.

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.

Radiographic Evaluation of Sleep-Disordered Breathing

Sleep-disordered breathing and obstructive sleep apnea are becoming more prevalent in today's population. Management of these conditions can be difficult and this diagnosis is often overlooked by clinicians. An increased awareness and understanding of craniofacial structures and anatomic relationships can aid the clinician in identifying at-risk patients, and improve treatment outcomes. An airway review of 3-dimensional computed tomography imaging can identify (1) anatomic variations that contribute to obstructive airway complications, and (2) measurable dimensions to identify at risk patients. This article provides instruction on the key anatomic landmarks and imaging protocols for radiographic airway evaluation.

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.

Effect of orthodontic treatment on the upper airway volume in adults

INTRODUCTION

The aim of this study was to examine the effects of orthodontic treatment with and without extractions on the anatomic characteristics of the upper airway in adults.

METHODS

For this retrospective study, the pretreatment and posttreatment cone-beam computed tomography scans of 74 adult patients meeting defined eligibility criteria were analyzed. Imaging software was used to segment and measure upper airway regions including the nasopharynx, the retropalatal, and retroglossal areas of the oropharynx, as well as the total airway. The Wilcoxon signed rank test was used to compare volumetric and minimal cross-sectional area changes from pretreatment to posttreatment.

RESULTS

The reliability values were high for all measurements, with intraclass correlation coefficients of 0.82 or greater. The volumetric treatment changes for the extraction and nonextraction groups were as follows: total airway, 1039.6 ± 3674.3 mm³ vs 1719.2 ± 4979.2 mm³; nasopharynx, 136.1 ± 1379.3 mm³ vs -36.5 ± 1139.8 mm³; retropalatal, 412.7 ± 3042.5 mm³ vs 399.3 ± 3294.6 mm³; and retroglossal, 412.5 ± 1503.2 mm³ vs 1109.3 ± 2328.6 mm³. The treatment changes in volume or minimal cross-sectional area for all airway regions examined were not significantly (P >0.05) different between the extraction and nonextraction groups.

CONCLUSIONS

Orthodontic treatment in adults does not cause clinically significant changes to the volume or the minimally constricted area of the upper airway. These results suggest that dental extractions in conjunction with orthodontic treatment have a negligible effect on the upper airway in adults.

Changes in pharyngeal airway dimensions and hyoid bone position after maxillary protraction with different alternate rapid maxillary expansion and construction protocols: A prospective clinical study

OBJECTIVE

To evaluate the changes in pharyngeal airway dimensions and the position of the hyoid bone after maxillary protraction with different alternate rapid maxillary expansion and construction (Alt-RAMEC) protocols in patients with skeletal class III malocclusion as a result of maxillary retrusion.

MATERIAL AND METHODS

The patients with skeletal class III malocclusions were consecutively divided into two groups. Group 1 consisted of 17 patients (11 boys and 6 girls, mean age 11.31 ± 1.71 years) who had the Alt-RAMEC protocol for 5 weeks, and group 2 consisted of 17 patients (10 boys and 7 girls, mean age 11.64 ± 1.24 years) who had the Alt-RAMEC procedure for 9 weeks. In this study, 4 angular and 13 linear measurements were performed to evaluate the skeletal and pharyngeal airway changes that occurred after maxillary protraction.

RESULTS

A significant increase in the maxillary growth, inhabitation of mandibular growth, and clockwise rotation of the mandible caused the improvement of the maxillo-mandibular relationship in both groups. Those changes caused a significant increase in the upper pharyngeal airway dimension (P < .01) and affected the vertical position of the hyoid bone in both groups (P < .05 and P < .01, respectively). However, changes that occurred in both groups were found to be similar for all airway variables (P > .05).

CONCLUSION

Upper pharyngeal dimension and vertical position of the hyoid bone were affected by the maxillary protraction with different Alt-RAMEC protocols. There were no statistically significant differences between the groups.

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.

Effects of zygoma-gear appliance for unilateral maxillary molar distalization: A prospective clinical study

INTRODUCTION

The aim of the study was to evaluate the dentoskeletal effects of the zygoma-gear appliance used for unilateral maxillary molar distalization in patients with Class II subdivision malocclusion.

METHODS

This prospective clinical study consisted of 21 patients (9 boys, 12 girls; mean age, 15.68 ± 2.18 years) with unilateral Class II malocclusion treated using the unilateral zygoma-gear appliance supported by a zygomatic miniplate inserted on the Class II malocclusion side. The dentoskeletal effects of the system were evaluated using cephalometric lateral and panoramic films with a paired t test.

RESULTS

The mean amount of distalization for the maxillary first molar was found to be 5.31 ± 2.46 mm (P <0.001) in 0.45 ± 0.12 years, showing an amount of 0.98 mm of distalization per month. It was also accompanied by a slight intrusion (0.76 ± 2.85 mm; P >0.05) and distal tipping (6.39° ± 5.39°; P <0.001) of the maxillary molars. The maxillary premolar also spontaneously moved distally 1.63 ± 1.90 mm (P <0.01) with distal tipping (4.05° ± 3.47°; P <0.001). Moreover, the inclination of the maxillary incisors and overjet were decreased (-1.59° ± 1.45°, P <0.001; and -0.29 ± 0.63 mm, P <0.05; respectively) showing no anchorage loss. No statistically significant changes were found for the skeletal and soft tissue measurements (P >0.05).

CONCLUSIONS

The zygoma-gear appliance system is an effective method for unilateral maxillary molar distalization.

Pharyngeal airway effects of Herbst and skeletal anchored Forsus FRD EZ appliances

BACKGROUND AND OBJECTIVE

To evaluate the skeletal and pharyngeal airway effects of skeletal anchored Forsus FRD EZ appliance using bilateral miniplates inserted on mandibular symphyses and to compare the findings with a well matched control group treated using a Herbst appliance.

METHODS

Thirty patients with skeletal Class II malocclusion due to mandibular retrusion were divided into two groups. Group 1 consisted of 15 patients (8 females and 7 males; mean age: 13.11 ± 1.29 years) treated using the Herbst appliance and Group 2 consisted of 15 patients (9 females and 7 males; 12.84 ± 1.27 years) treated using the skeletal anchored Forsus FRD EZ appliance. Treatment changes were assessed by means of linear, angular, and area measurements.

RESULTS

The groups were well matched regarding to the chronological ages, gender distribution and initial cephalometric values (P > 0.05). In both groups, skeletal Class II malocclusion was corrected by decrease in SNA and increase in SNB, Co-Gn, VRL-B and VRL-Pog measurements. Those changes caused a significant correction in the maxillo-mandibular relationship. Upper and lower pharyngeal airway dimensions were increased in both group, while the increase in the lower pharyngeal dimension was found to be statistically significant in the skeletal anchored Forsus FRD EZ group (P < 0.05). Oropharyngeal area measurements significantly increased in both groups (P < 0.001 and P < 0.01, respectively). Comparison of the groups showed that both groups had similar changes with no statistically significant differences (P > 0.05).

CONCLUSION

Skeletal changes produced by both appliances caused significant pharyngeal airway changes.

Volumetric changes in pharyngeal airway in Class II division 1 patients treated with Forsus-fixed functional appliance: A three-dimensional cone-beam computed tomography study

Objective:

Recent years have witnessed a renewed interest to determine a quantifiable relationship between mandibular advancement performed with an orthodontic appliance and the resulting airway volume. The study was conducted to evaluate the volumetric changes in pharyngeal airway space using cone-beam computed tomography (CBCT) in Class II division 1 patients with retrognathic mandible treated by Forsus-fixed functional appliance and to compare them with their pretreatment findings.

Materials and Methods:

Thirty patients with Class II division 1 malocclusion of age group 10–17 years were selected randomly and evaluated for changes in pharyngeal airway volume with and without Forsus-fixed functional appliance. Patients in each group underwent CBCT scan of head and neck region at pretreatment stage and 6 months after the initial scan. Institutional approval for the project was obtained from the Ethical Committee. Volumetric changes of upper (oropharynx) and lower (hypopharynx) pharyngeal airways were measured on scanogram using computer software and intragroup comparisons were done.

Results:

There was a statistically significant increase in the volume of both hypopharynx and oropharynx and also total airway volume in patients treated with Forsus-fixed functional appliance. Three-dimensional reconstruction of the airway also demonstrates a considerable increase in pharyngeal airway space.

Conclusion:

Forsus-fixed functional appliance can be a promising appliance for improving pharyngeal airway volume in Class II division 1 patients with retrognathic mandible thus preventing obstructive sleep apnea and other respiratory problems in future. However, the long-term implications of this treatment modality need further consideration and a longer period of follow-up.

Mandibular vertical asymmetry in adult orthodontic patients with different vertical growth patterns: A cone beam computed tomography study

OBJECTIVE

To evaluate condylar and ramal vertical asymmetry in adult orthodontic patients with different vertical growth patterns and a clinically normal sagittal skeletal pattern using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

The study sample consisted of 101 adult orthodontic patients (48 men and 53 women) divided into three groups according to their vertical growth patterns: high- (33 patients; mean age, 25.06 ± 6.05 years), low- (34 patients; mean age, 24.88 ± 5.22 years), and normal-angle (34 patients; mean age, 24.14 ± 4.26 years) groups. Condylar, ramal, condylar plus ramal height, and index measurements were performed using CBCT images and analyzed using one-way analysis of variance and post hoc Tukey tests.

RESULTS

There was no statistically significant difference in height measurements between right and left sides in each group, except a slight difference of approximately 0.5 mm for condylar height (CH) in the low-angle group (P < .05). No statistically significant gender differences were found for the values (P > .05). In the high-angle group, the ramal height (RH) and condylar plus ramal height (CH + RH) on both sides were found to be less than those of the low- (P < .001) and normal-angle groups (P < .017 and P > .017, respectively), and the asymmetry index values were slightly higher than those of the low- and normal-angle groups (P > .05).

CONCLUSIONS

The high-angle group showed statistically significantly smaller values of RH and CH + RH on both sides and statistically insignificantly higher asymmetry index values than the low- and normal-angle groups.

Evaluation of the mandibular volume and correlating variables in patients affected by unilateral and bilateral cleft lip and palate: a cone-beam computed tomography study

OBJECTIVES

The aims of the present study were to evaluate the mandibular volume in patients affected by unilateral (UCLP) and bilateral cleft lip and palate (BCLP) and to compare the findings with a well-matched normal occlusion sample without cleft.

MATERIALS AND METHODS

The study sample consisted of 66 patients divided into UCLP (24 patients; mean age, 14.46 ± 3.24 years), BCLP (17 patients; mean age, 14.28 ± 2.85 years), and control (25 patients; mean age, 14.40 ± 2.81 years) groups. The volume of the mandible including the condyle and the roots of the teeth and craniofacial measurements were performed using cone-beam computed tomography and analyzed using the one-way variance analysis and post hoc Tukey's tests. Regression analyses were used to evaluate the relationships of the measurements and the mandibular volume.

RESULTS

Patients affected by UCLP and BCLP had similar craniofacial features (p > 0.05), including decreased SNB, Co-A, Co-Gn, Co-Go, and Go-Gn and increased ANB and SN-MP measurements compared to the control group. Both UCLP and BCLP groups had decreased values of mandibular volume compared to the normal occlusion group, while these differences were found to be statistically insignificant (p > 0.05). Co-Go (Beta = 0.420; p = 0.014) and Co-Gn variables (Beta = 0.708; p = 0.045) were positively correlated with mandibular volume, while SNB (Beta = -0.669; p = 0.044) and SN-MP (Beta = -0.358; p = 0.049) variables were negatively correlated (R (2) = 60.3 and p = 0.000).

CONCLUSION

Mandibular volume insignificantly differs in cleft patients (p > 0.05), and the variables of Co-Go, Co-Gn, SNB, and SN-MP significantly correlate with the volume.

CLINICAL RELEVANCE

This article investigates mandibular volume in patients affected by UCLP and BCLP that has never been investigated in the literature. The present study showed that both UCLP and BCLP groups had insignificantly decreased values of mandibular volume compared to the normal occlusion group.

Evaluation of dehiscence and fenestration in adolescent patients affected by unilateral cleft lip and palate: A retrospective cone beam computed tomography study

OBJECTIVE

To evaluate the presence of dehiscence and fenestration defects around anterior teeth in the cleft region and to compare these findings with the noncleft side in the same patients using cone beam computed tomography (CBCT).

MATERIALS AND METHODS

CBCT scans of 44 patients (26 males, 18 females; mean age, 14.04 ± 3.81 years) with unilateral cleft lip and palate (UCLP) were assessed to define dehiscences and fenestrations of the anterior teeth in both cleft and noncleft sides of the UCLP patients and a control group of noncleft patients (51 patients; 21 males, 30 females; mean age, 14.52 ± 1.16 years). Data were analyzed using Pearson's χ(2) and Student's t-test.

RESULTS

The prevalence of dehiscences at the maxillary central incisors, lateral incisors, and canines teeth were 43.2%, 70.6%, and 34.1% on the cleft side and 22.7%, 53.1%, and 27.3% on the noncleft side of UCLP patients, and 13.7%, 7.8%, and 13.7% in controls, respectively (statistically no difference between the sides of cleft patients). The cleft patients had a statistically significantly higher prevalence of dehiscences than did the controls on both the cleft and noncleft sides (P < .05), except for the maxillary central incisors. Fenestrations for these teeth were significantly more common on the cleft side in UCLP patients compared with controls (P < .05), whereas the difference for maxillary lateral incisors was not statistically significant.

CONCLUSIONS

Patients with UCLP showed a higher prevalence of dehiscence and fenestration defects around the maxillary anterior teeth.

CBCT in orthodontics: assessment of treatment outcomes and indications for its use

Since its introduction into dentistry in 1998, CBCT has become increasingly utilized for orthodontic diagnosis, treatment planning and research. The utilization of CBCT for these purposes has been facilitated by the relative advantages of three-dimensional (3D) over two-dimensional radiography. Despite many suggested indications of CBCT, scientific evidence that its utilization improves diagnosis and treatment plans or outcomes has only recently begun to emerge for some of these applications. This article provides a comprehensive and current review of key studies on the applications of CBCT in orthodontic therapy and for research to decipher treatment outcomes and 3D craniofacial anatomy. The current diagnostic and treatment planning indications for CBCT include impacted teeth, cleft lip and palate and skeletal discrepancies requiring surgical intervention. The use of CBCT in these and other situations such as root resorption, supernumerary teeth, temporomandibular joint (TMJ) pathology, asymmetries and alveolar boundary conditions should be justified on the basis of the merits relative to risks of imaging. CBCT has also been used to assess 3D craniofacial anatomy in health and disease and of treatment outcomes including that of root morphology and angulation; alveolar boundary conditions; maxillary transverse dimensions and maxillary expansion; airway morphology, vertical malocclusion and obstructive sleep apnoea; TMJ morphology and pathology contributing to malocclusion; and temporary anchorage devices. Finally, this article utilizes findings of these studies and current voids in knowledge to provide ideas for future research that could be beneficial for further optimizing the use of CBCT in research and the clinical practice of orthodontics.

Changes in difficult airway predictors following mandibular setback surgery

The aim of this study was to determine the effect of surgical mandibular backward movements on the predictors of a difficult airway. Thirty-seven skeletal class III patients were included in this study. The Mallampati score, body mass index (BMI), maximal inter-incisal distance, and thyromental and sternomental distances of these patients were evaluated preoperatively and at 6 months and 2 years postoperatively. A sagittal split ramus osteotomy (SSRO) without genioplasty was performed in all patients by the same surgical team, and anaesthesia was provided by the same anaesthesiologist using nasotracheal intubation. The paired samples t-test and Wilcoxon signed-rank test were used for statistical comparisons of the data. There were no statistically significant changes in BMI or sternomental and thyromental distances after SSRO. The maximal inter-incisal distance was significantly reduced at 6 months postoperatively (P<0.05), but no statistical difference was found between the values obtained preoperatively and at 2 years postoperative. A statistically significant increase in Mallampati score was observed postoperatively (P<0.05). Both the patient and practitioner should be aware of the risks associated with an increased postoperative Mallampati score in mandibular setback patients. The amount of mandibular setback in skeletal class III patients with a high preoperative Mallampati score should be limited to prevent potential postoperative airway problems.

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.