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 mm³) 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 mm³) and significantly decreased in the control (mean  =  11,826.1 ± 4831.9 mm³; P  =  .008) and high angle (mean  =  10,869.1 ± 4084.1 mm³; P  =  .001) groups. Total airway volume was highest in the low-angle group (mean  =  24,261.6 ± 8470.1 mm³) and lowest in the high-angle group (mean  =  16,937.0 ± 5027.4 mm³; P < .001).Conclusion:The null hypothesis was rejected. Significant differences were found in pharyngeal airway volumes among different skeletal vertical patterns.     

Three-dimensional analysis of upper airway morphology in skeletal Class III patients with and without mandibular asymmetry

Objective:To compare the three-dimensional (3D) morphology of the upper airway in skeletal Class III patients with and without mandibular asymmetry and to investigate the possible underlying correlations between the morphology of the upper airway and mandibular deviation.Materials and Methods:Cone-beam computed tomography images of 54 subjects with skeletal Class III malocclusion (ANB angle ≤ 0.4°, Wits ≤ −5.5°) were taken and 3D upper airway models were reconstructed using Dolphin 3D software. According to the distance (d) from symphysis menti to the sagittal plane, all subjects were divided into a symmetry group (d ≤ 2 mm) and an asymmetry group (d ≥ 4 mm). Based on the severity of mandibular deviation, the asymmetry group was divided into subgroup I (4 mm ≤d <10 mm) and subgroup II (d ≥ 10 mm). Cross-sectional linear distances, areas, and volumetric variables of the upper airway were measured in the 3D airway model.Results:Width of the inferior limit of the glossopharynx (P3W), cross-sectional area of the anterior limit of the nasal airway (P5S), and height of the glossopharynx (GPH) in the asymmetry group were significantly larger than in the symmetry group. As for subjects with severe mandibular deviation in subgroup II (d ≥ 10 mm), volume of the glossopharynx (GPV), total volume of the pharynx (TPV), length of the inferior limit of the velopharynx (P2L), and ratio of length to width of the inferior limit of the velopharynx (P2L/P2W) showed significantly negative correlations with mandibular deviation (r > 0.7, P < .05).Conclusions:In Class III subjects with severe mandibular asymmetry, the pharyngeal airway showed a tendency toward constriction and presented a more elliptical shape as mandibular deviation became more severe (P < .01).     

不同骨面型青少年上气道的锥体束CT分析

目的 通过锥体束CT（cone-beam computed tomographs,CBCT）研究不同垂直骨面型和不同矢状骨面型青少年正畸患者上气道的差异.方法 采集66例青少年患者的术前CBCT影像,平均年龄（12.74±1.75）岁.根据中国人正常（牙合）Steiner分析法按ANB角、SN-MP角分成Ⅰ类、Ⅱ类、Ⅲ类和高角、均角、低角组.用InvivoDental 5.1软件测量口咽部气道的体积、最小横截面面积和长度.单因素方差分析比较不同骨面型青少年正畸患者气道的差异.结果 1.不同矢状骨面型青少年患者中,骨性Ⅰ类、Ⅱ类、Ⅲ类患者气道体积分别为（14.83±13.46） cm3、（8.77±3.54） cm3、（17.23±4.85） cm3,最小横截面面积分别为（160.93±90.43） mm2、（103.81±50.65） mm2、（200.57±66.76） mm2,而气道长度分别为（52.37±5.82） mm、（56.15±7.51） mm、（52.27±5.23）mm,差异都有统计学意义（P＜0.05）;2.不同垂直骨面型的青少年患者气道体积、长度及最小横截面积之间均无统计学差异（P＞0.05）.结论 青少年患者气道形态与矢状骨面型相关,与垂直骨面型无明显相关.     

不同矢状骨面型错殆畸形患者气道大小形态的CBCT研究

目的：研究不同矢状骨面型错殆畸形患者口咽部气道大小及三维形态的差异,探讨颅面结构与上气道形态之间的关系。方法：收集90例成年错殆畸形患者（18-40岁）正畸治疗前锥束CT资料,根据ANB角的大小分成Ⅰ类,Ⅱ类,Ⅲ类3种不同矢状骨面型组,每组30例。利用Mimics10．01软件测量口咽部气道体积、面积、高度、最小截面处矢状径与横径的比值及截面面积,在SPSS13．0统计数据包中利用单因素方差分析比较3组气道大小及形态之间的差异。结果：口咽气道体积：Ⅱ类、Ⅰ类、Ⅲ类逐渐变大,气道高度：Ⅱ类、Ⅰ类、Ⅲ类逐渐变小,Ⅱ类患者舌咽部气道的体积和平均截面积明显小于Ⅰ类和Ⅲ类的患者,3种不同矢状骨面型组之间口咽部气道最小截面面积差异有统计学意义。结论：从Ⅲ类,Ⅰ类到Ⅱ类患者口咽气道的形态是由宽阔型向狭长型转变,Ⅱ类患者呈现明显狭长的口咽气道形态。     

Evaluation of mandibular volume classified by vertical skeletal dimensions with cone-beam computed tomography

Objective:To investigate the relationship between anteroposterior and vertical differences in maxillofacial morphology and mandibular volume.Materials and Methods:Subjects comprised 213 Japanese adults (84 males and 129 females) who were divided into three groups based on mandibular basal arch (ANB) and Wits, measured in a cephalometric analysis: Class I (−1° ≤ ANB < 4°,−1 mm ≤ Wits < 0 mm), Class II (ANB ≥ 4°, Wits ≥ 0), and Class III (ANB <−1°, Wits <−1 mm). Subjects were also divided into three groups based on the mandibular plane angle (Mp), as follows: hypodivergent (Mp < 23°), normodivergent (Mp  =  23–30°), and hyperdivergent (Mp > 30°) groups. Mandibular volume was measured from cone-beam computed tomographic images that were analyzed using Analyze™ image processing software and compared among the three groups in each classification.Results:No significant differences were noted in mandibular volume among Classes I, II, and III. An inverse relationship was found between mandibular volume and Mp, and a significant difference was noted in mandibular volume between the hypodivergent and hyperdivergent groups.Conclusions:In addition to two-dimensional analysis, such as lateral cephalometry, three-dimensional information such as volume, provided by cone-beam computed tomography, contributes to a more detailed assessment of maxillofacial morphology.     

Comparison of condylar size among different anteroposterior and vertical skeletal patterns using cone-beam computed tomography

Objectives:To compare condylar size among different anteroposterior and vertical skeletal patterns using cone-beam computed tomography (CBCT).Materials and Methods:The study included 166 subjects (61 men, mean age: 27.2 ± 7.6 years; 105 women, mean age: 27.4 ± 9.2 years). The anteroposterior skeletal patterns of the subjects were classified into Classes I (−1° ≤ A point–nasion–B point angle [ANB] < 4°), II (ANB ≥ 4°), and III (ANB < −1°). The vertical skeletal patterns were classified into hypodivergent (mandibular plane [MP] ≤ 23°), normodivergent (23° < MP < 30°), and hyperdivergent (MP ≥ 30°) groups. The condylar length, height, and width were examined using CBCT images. Analysis of covariance was used to compare three condylar size measurements among the three anteroposterior groups and the three vertical groups using sex as a covariate. Both left and right sides were examined. Nine groups were further divided according to the anteroposterior and vertical groups, and two-way analysis of covariance (ANCOVA) was applied to estimate the composite effect of skeletal patterns in both directions.Results:Sex as a covariate showed statistical significance in most examinations. The condylar height on both sides had statistically different anteroposterior skeletal patterns (P < .001). The condylar width on both sides also had statistically different vertical skeletal patterns (P < .001). After adjusting for sex, the condylar height and width on both sides increased from Class II, Class I, and Class III. The condylar width on both sides increased from the hypodivergent group, the normodivergent group, and the hyperdivergent group. No composite effect of skeletal patterns in both directions was observed.Conclusions:Condylar height and width considerably differed among subjects with different anteroposterior or vertical skeletal patterns. The anteroposterior or vertical skeletal patterns independently affected the condylar size.     

两种方法矫治骨性Ⅲ类错[牙合]前、后上气道变化的临床研究

目的探讨微种植体支抗与颌间Ⅲ类牵引矫治成人骨性Ⅲ类错[牙合]前后上气道矢状径的变化,为临床治疗提供参考。方法选取35例成人骨性Ⅲ类错[牙合]患者,利用直丝弓矫治技术矫治,微种植体组15例(A组):骨性Ⅲ类错[牙合]重度病例(垂直高角)选择配合微种植体支抗;颌间Ⅲ类牵引组20例(B组):骨性Ⅲ类错[牙合]轻、中度病例(垂直低角、均角)选择配合颌间Ⅲ类牵引,测量分析矫治前后的头颅定位侧位片。结果矫治后颅颌面测量指标的变化:A组蝶鞍中心鼻根点下牙槽座点构成的角(sellanasionsupramental angle,SNB角)减小(P<0.05),上牙槽座点鼻根点下牙槽座点构成的角(subspinalenasionsupramental angle,ANB角)增大(P<0.05);B组SNB角减小(P<0.05),蝶鞍中心鼻根点上牙槽座点构成的角(sellanasionsubspinale angle,SNA角)、ANB角、下颌平面角(anterior skull base planemandibular plane angle,SNMP角)增大(P<0.05)。矫治后上气道矢状径测量指标的变化:A组上气道矢状径舌咽段(TBTPPW)减小(P<0.05);B组上气道矢状径鼻咽第一段(PNSR)增大(P<0.05)。矫治后A组SNB减小、ANB增大的量大于B组,差异有统计学意义(P<0.05);A组上气道TB-TPPW减小的量大于B组,差异有统计学意义(P<0.05)。结论利用微种植体支抗矫治成人骨性Ⅲ类错[牙合],对上气道矢状径舌咽段产生消极影响。     

Proximity of upper central incisors to incisive canal among subjects with maxillary dentoalveolar protrusion in various facial growth patterns:: A CBCT analysis

ObjectiveTo investigate the position of the upper central incisor roots (U1) relative to the incisive canal (IC) among subjects with maxillary dentoalveolar protrusion in various facial growth patterns.Materials and Methods240 cone beam computed tomography images of skeletal Class I and II maxillary or bimaxillary protrusive subjects with a mean age of 23.74 ± 3.73 years were enrolled according to their facial growth pattern. The IC volume was measured using Mimics 21 software (Materialise, Leuven, Belgium). The U1 inter-root distance, width of IC, and their proximity were estimated using Invivo6 software (Anatomage, San Jose, CA).ResultsThe IC volume was slightly greater among the high angle facial group and female patients than the other groups. Overall, the IC width was greater than the U1 inter-root distance in 55.65%, 57.6%, and 65% among the average, low, and high angle facial groups, respectively, and in 56.5% and 62.9% of males and females, respectively. The overall anteroposterior (sagittal) distances between the U1 roots and IC were 4.36 ± 1.18, 4.78 ± 1.17, and 3.83 ± 0.90 mm among the average, low, and high angle facial groups, respectively.ConclusionsThe high angle facial group and female patients showed slightly greater IC dimensions than the other groups. The overall maximum sagittal distances between the U1 and IC were around 5.5, 6, and 4.7 mm among the average, low, and high angle facial groups, respectively. The low angle facial group and male patients tended to have greater sagittal distances. Therefore, the present findings could serve as a guideline when a considerable amount of upper incisor retraction is planned for Class I or II maxillary or bimaxillary dentoalveolar protrusion patients.     

Cephalometric Characteristics of Korean Children with Class III Malocclusion in the Deciduous Dentition

Objective:To compare the cephalometric characteristics of children with Class III malocclusion to those of children with normal occlusion during the deciduous dentition phase.Materials and Methods:Cephalometric measurements of 27 children (mean age: 5.03 years) diagnosed with Class III malocclusion were compared with 32 children (mean age: 4.85 years) diagnosed with normal occlusion in the following four categories: sagittal skeletal analysis, vertical skeletal analysis, dentoalveolar analysis, and soft tissue analysis.Results:Significant differences were seen in all categories except vertical skeletal analysis. Sagittal skeletal measurements included ANB (Class III group: −0.91 ± 1.60; normal group: 5.28 ± 1.29), facial convexity (Class III group: 0.47 ± 4.32; normal group: 13.65 ± 3.44), Wits appraisal (Class III group: −5.54 ± 2.36; normal group: −0.84 ± 1.91), and A to N-perpendicular (Class III group: −2.94 ± 3.05; normal group: 0.78 ± 2.53). Dentoalveolar measurements included U1 to NA (Class III group: 11.98 ± 5.25; normal group: 8.12 ± 5.43), IMPA (Class III group: 81.34 ± 7.40; normal group: 86.57 ± 5.67), and interincisal angle (Class III group: 152.65 ± 8.82; normal group: 145.03 ± 7.34). Soft tissue measurements included soft tissue convexity (Class III group: 2.47 ± 4.20; normal group: 12.71 ± 3.95), nasofacial angle (Class III group: 22.68 ± 4.22; normal group: 26.24 ± 3.84), and upper lip to esthetic plane (Class III group: −0.65 ± 2.74; normal group: 3.07 ± 1.90).Conclusions: There are significant differences between the craniofacial patterns of normal children and those of children with Class III malocclusion that can be identified with cephalometric analysis as early as the deciduous dentition phase.     

Craniofacial features of patients with sickle cell anemia and sickle cell trait

Objective:To identify the craniofacial characteristics of patients with sickle cell trait (SCT) and sickle cell anemia (SCA) and to compare these measurements with those of nonaffected subjects.Materials and Methods:Clinically normal patients and those with SCT and SCA were evaluated in this study. The patients were divided into three groups: normal (control), SCA, and SCT (n  =  with 15 in each group). Inclusion criteria were SCA or SCT verified by laboratory methods and no treatment with fixed orthodontics or facial orthopedics. Lateral cephalometric radiographs were carried out and were used to obtain angular and linear measurements of anatomic structures displayed. All markings and measurements were performed by a single examiner.Results:The average ANB was increased in groups with SCA (5.47 ± 2.0°) and SCT (3.80 ± 1.4°), indicating a tendency to Class II. The mean SNA angle was 83.0 ± 3.8° and 82.1±3.5° for SCA and SCT, indicating a proper positioning of the jaw from the skull base. There was an interaction between the group and sex factors for the variable SN-GoGn; measures were higher for men in the SCA group.Conclusion:Patients with SCA and SCT exhibited characteristics of Class II skeletal pattern because of mandibular retrusion. Most patients showed no compensatory maxillary expansion, which was determined by the normal jaw length and absence of maxillary protrusion.     

Cone-beam evaluation of pharyngeal airway space in adult skeletal Class II patients with different condylar positions

Objectives:To test the null hypothesis that there is no significant difference in pharyngeal airway space among adult skeletal Class II patients with different condylar positions using cone-beam computed tomography (CBCT).Materials and Methods:The CBCT records of 60 patients with skeletal Class II malocclusion (ANB angle ≥ 4°, Wits ≥ 0) were selected from the CBCT database. According to the condyle position, the patients were divided in three groups: anterior group (CD ≤ −12%), centric group (−12% ≤ CD ≤ +12%), and posterior group (CD ≥ +12%). Three-dimensional (3D) pharyngeal airway models were reconstructed using InvivoDental software 5.1.3. The volume and area of the pharyngeal airway space were measured in the 3D airway model.Results:The volume and area of the pharyngeal airway space in the centric group were significantly smaller than those in the posterior group (P < .01). The volume and area of the pharyngeal airway space were smallest in the anterior group and significantly increased in the centric and posterior groups (P < .001).Conclusions:The null hypothesis was rejected. Significant differences were noted in pharyngeal airway space among adult skeletal Class II patients with different condylar positions.     

Anterior maxillary dentoalveolar and skeletal cephalometric factors involved in upper incisor crown exposure in subjects with Class II and III skeletal open bite

Objective:To compare the anterior dentoalveolar and skeletal maxillary cephalometric factors involved in excessive upper incisor crown exposure (UICE) in subjects with skeletal open bite Class II (SOBCIIG) and Class III (SOBCIIIG) against an untreated control group (CG).Materials and Methods:Seventy pretreatment lateral cephalograms of orthodontic young adult patients (34 men, 36 women) were examined. The sample was divided into three groups according to both sagittal and vertical growth pattern and occlusion. The CG group (n  =  25) included Class I, normodivergent cases with adequate overbite, and the SOBCIIG group (n  =  25) and SOBCIIIG group (n  =  20) included skeletal Class II or III malocclusions, respectively, with hyperdivergent pattern and negative overbite. Several cephalometric measurements were considered (skeletal and dental). Analysis of variance, multivariate analysis of covariance, and Tukey HSD post hoc tests were used. Principal component analysis (PCA) was used for reducing the number of cephalometric variables related to UICE. Finally, a multiple linear regression was calculated.Results:Significant differences in UICE were found between the groups (P < .05). UICE was 3.9 mm in SOBCIIG, 2.5 mm in SOBCIIIG, and 0.4 mm in CG. PCA showed that a nondental component—including vertical maxillary height (VMH) and upper lip height (ULH)—was the only component significantly associated with UICE. The regression model had a moderate prediction capability.Conclusions:Although the UICE was statistically different in SOBCIIG, the values were within the esthetic standards. The UICE was mainly influenced by VMH and ULH.     

Changes in apical base sagittal relationship in Class II malocclusion treatment with and without premolar extractions: A systematic review and meta-analysis

Objective:To evaluate the changes in apical base sagittal relationship in Class II treatment with and without premolar extractions.Materials and Methods:Controlled studies evaluating ANB angle changes after Class II Division 1 malocclusion treatment with or without premolar extractions were considered. Electronic databases (PubMed, Embase, Web of Science, Scopus, The Cochrane Library, Lilacs, and Google Scholar) without limitations regarding publication year or language were searched. Risk of bias was assessed with Risk Of Bias in Non-randomized Studies—of Interventions tool of the Cochrane Collaboration. Mean difference (MD) and 95% confidence interval (CI) were calculated from the random-effects meta-analysis. Subgroup and sensitivity analyses were also performed.Results:Twenty-five studies satisfied the inclusion criteria and were included in the qualitative synthesis. Eleven nonextraction and only one extraction Class II treatment studies presented untreated Class II control group. Therefore, meta-analysis was performed only for the nonextraction protocol. In treated Class II nonextraction patients, the average of the various effects was a reduction in the ANB angle of 1.56° (95% CI: 1.03, 2.09, P < .001) compared with untreated Class II subjects. Class II malocclusions treated with two maxillary-premolar extractions and four-premolar extractions produced estimated mean reductions in ANB of −1.88° and −2.55°, respectively. However, there is a lack of low-risk-of-bias studies.Conclusions:According to the existing low quality evidence, the apical base sagittal relationship in nonextraction, two-maxillary and four-premolar extractions Class II treatments decreases −1.56°, 1.88° and 2.55°, respectively. Further studies are necessary to obtain more robust information.     

Soft tissue airway dimensions and craniocervical posture in subjects with different growth patterns

Objective:To compare the dimensions of the nasopharynx and oropharynx of subjects with different growth patterns and to determine whether any correlation exists with their craniocervical posture.Materials and Methods:Cephalometric radiograph of 60 subjects (16–25 years old), taken in natural head position, were divided into three groups according to the mandibular plane angle: hypodivergent (SN/MP <26°), normodivergent (SN/MP 26°–38°), and hyperdivergent (SN/MP <38°). Correlations were calculated between nasopharyngeal area, oropharyngeal area, and craniocervical posture. Continuous variables were compared by one-way analysis of variance, and the significance of mean difference between the groups was done by the Tukey post hoc test. A value of P < .05 was considered statistically significant.Results:Patients in the hyperdivergent group were found to have significantly smaller nasopharyngeal and oropharyngeal areas than the other groups (P < .001 and P < .05, respectively). Similarly, the oropharyngeal area in the normodivergent group was significantly smaller than that in the hypodivergent group (P < .05). However, no significant differences were found in the nasopharyngeal area between the hypodivergent and normodivergent groups and between the hyperdivergent and normodivergent groups (P > .05). Reduced pharyngeal airways were typically seen in patients with a large craniocervical angle and a large mandibular inclination.Conclusions:Smaller nasopharyngeal and oropharyngeal airways were seen in connection with a large craniocervical and a large mandibular inclination. We therefore suggest that the vertical skeletal pattern may be one of the factors that contribute to nasopharyngeal and oropharyngeal obstruction.     

不同矢状骨面型无鼾症青年上气道形态的锥形束CT分析

目的研究不同矢状骨面型的无鼾症青年错牙合畸形患者上气道形态和舌骨位置的差异。方法在自然头位下,对Ⅰ类、Ⅱ类和Ⅲ类矢状骨面型无鼾症青年错牙合畸形患者各30例进行锥形束CT扫描,借助Dolphin imaging 11.0图像分析软件进行三维重建,并分别测量上气道腭后区、舌后区的矢状径、横径、轴面面积以及上气道容积,最小轴面面积和上气道长度。使用Winceph 7.0软件对侧位片进行头影测量以及舌骨位置的测量,并对测量结果进行统计学分析。结果Ⅰ类、Ⅱ类矢状骨面型组舌后区及腭后区轴面面积均小于Ⅲ类矢状骨面型组。Ⅱ类矢状骨面型组与Ⅲ类矢状骨面型组间的舌后区矢状径,横径,上气道容积,舌骨位置有显著差异性。结论不同矢状骨面型无鼾症青年错牙合畸形患者上气道形态和舌骨位置存在一定的差异,差异有统计学意义。矢状向颌骨关系对上气道形态和舌骨位置有一定影响。     

Chin cup effects using two different force magnitudes in the management of Class III malocclusions

Objectives:To evaluate the dental and skeletal effects of chin cup using two different force magnitudes in the management of Class III malocclusion cases.Materials and Methods:Fifty growing patients (26 males and 24 females) with skeletal Class III and mandibular prognathism were selected. The patients were divided into three groups. Patients in group 1 (n  =  20) were treated with a chin cup and occlusal bite plane using 600 g of force per side. Patients in group 2 (n  =  20) were subjected to the same treatment as in group 1 but using 300 g of force per side. In group 3 (n  =  10) no treatment was performed. For all patients, lateral cephalograms were taken before treatment and after 1 year. Cephalograms were traced and analyzed. The collected data were analyzed statistically using one-way analysis of variance and the Tukey test.Results:In the treatment groups, the SNB angle and ramus height decreased significantly. The ANB angle, Wits appraisal, anterior facial height, mandibular plane angle, and retroclination of the mandibular incisors were significantly increased in comparison to the control group. Utilization of either force showed no significant differences, except that the reduction in the ramus height was significantly greater with the use of higher force.Conclusions:The use of a chin cup improved the maxillomandibular base relationship in growing patients with Class III malocclusion but with little skeletal effect. The utilization of either force had the same effects, except that the higher force had a more pronounced effect in reduction of ramus height.     

Uvulo-glosso-pharyngeal dimensions in different anteroposterior skeletal patterns

The aim of this study was to investigate the uvulo-glosso-pharyngeal dimensions in subjects with different anteroposterior jaw relationship. Cephalometric radiograph of 90 subjects (45 females and 45 males, aged 14-17 years) were divided into three groups according to the ANB angle, ie, group 1, skeletal Class I (ANB angle 1-5); group 2, skeletal Class II (ANB angle >5); and group 3, skeletal Class III (ANB angle <1). In addition, each group was divided into two subgroups according to sex. Statistical analysis was undertaken using analysis of variance and least significant difference test. Pearson's Correlation test was also performed. Sex differences were found in Class I and III subjects. No sex differences were detected in Class II subjects. On average, tongue length was significantly shorter in Class III subjects (P < .05), tongue height was reduced in Class II female subjects, the soft palate was thicker in Class III females and the vertical airway length (VAL) was reduced in Class II male subjects (P < .01). In Class II subjects, the hyoid bone was closer to the mandible vertically and to C3 horizontally compared with Class I (P < .01) and Class III (P < .001) male subjects. Anteroposterior skeletal pattern showed a weak, but significant correlation with inferior pharyngeal airway space (R = -0.24, P = .024), vertical position of hyoid bone in relation to mandibular plane (R = -0.26, P = .014), and anteroposterior position of hyoid bone in relation to C3 (R = -0.561, P = .000). In conclusion, uvulo-glosso-pharyngeal dimensions are affected by anteroposterior skeletal pattern.     

Upper airway changes after Xbow appliance therapy evaluated with cone beam computed tomography

Objective:To determine the treatment effects of the Xbow appliance on the upper airway dimensions and volume using cone-beam computed tomography (CBCT); to evaluate the cephalometric changes in the skeletal and dental structures of the skeletal Class II patients.Materials and Methods:The sample consisted of 25 Class II patients (11 male, 14 female) with a mean age of 11.1 ± 1.1 years. CBCT images were obtained at the beginning of the treatment (T0) and after the debonding of the Xbow (T1).Results:Changes in superior, middle, and inferior parts of the oropharynx in the retroglossal region and changes in the oropharyngeal airway volume were statistically significant (P < .05, P < .01). The differences favoring the Xbow for the changes in the direction of Class II correction included SNA, SNB, ANB, maxillary depth angles, and point A-NPg and Co-B distances. Data of the dental parameters showed palatal tipping and extrusion of the maxillary incisors, labial tipping of the mandibular incisors, and mesial movement and extrusion of the mandibular molars.Conclusions:Treatment with the Xbow appliance in Class II patients resulted in favorable increase in the oropharyngeal airway dimensions and volume. Further studies with larger study samples and with control groups are needed.     

隐形矫治器治疗骨性Ⅱ类高角患者上气道前后径及颌骨的变化

目的：探讨隐形矫治治疗骨性Ⅱ类高角患者上气道前后径及颌骨的变化。方法：将2016年6月—2018年6月西安交通大学口腔医院收治的拟进行隐形矫治的37例错畸形患者纳入研究。矫治前和矫治后18个月评估矫治效果,采用锥形束CT（CBCT）检查、测定上气道容积和舌体位置,头颅侧位片检查、测定上气道前后径和舌骨位置。收集大陆明星和患者矫治前、后侧面像制作侧貌剪影图,采用10级评分法评估侧貌美学效果。采用SPSS 20.0软件包对数据进行统计学分析。结果：矫治后患者口咽容积、舌咽容积和上气道最小截面积较矫治前显著增加（P<0.05）;矫治后患者下颌平面后部上气道前后径较矫治前显著增加（P<0.05）;矫治后患者ANB角、GoGn-SN角、OPP-SN角、Y轴角、UI-SN角、UI-PP角、UI-AP角和UI-AP距离较矫治前显著减小,SNB角和UI-LI角较矫治前显著增加（P<0.05）;矫治后患者侧貌美学评分显著大于矫治前（P<0.05）;矫治后患者侧貌美学评分显著小于明星（P<0.05）。结论：隐形矫治有利于骨性Ⅱ类高角患者上气道开放和颌骨畸形的纠正,具有良好的治疗效果并可获得满意的侧貌美学效果。