OBJECTIVE: The present study was designed to define a novel algorithm capable of predicting female adolescents\' cervical vertebrae maturation stage with high recall and accuracy.
METHODS: A total of 560 female cephalograms were collected, and cephalograms with unclear vertebral shapes and deformed scales were removed. 480 films from female adolescents (mean age: 11.5 years; age range: 6-19 years) were used for the model development phase, and 80 subjects were randomly and stratified allocated to the validation cohort to further assess the model\'s performance. Derived significant predictive parameters from 15 anatomic points and 25 quantitative parameters of the second to fourth cervical vertebrae (C2-C4) to establish the ordinary logistic regression model. Evaluation metrics including precision, recall, and F1 score are employed to assess the efficacy of the models in each identified cervical vertebrae maturation stage (iCS). In cases of confusion and mispredictions, the model underwent modification to improve consistency.
RESULTS: Four significant parameters, including chronological age, the ratio of D3 to AH3 (D3:AH3), anterosuperior angle of C4 (@4), and distance between C3lp and C4up (C3lp-C4up) were administered into the ordinary regression model. The primary predicting model that implements the novel algorithm was built and the performance evaluation with all stages of 93.96% for accuracy, 93.98% for precision, 93.98% for recall, and 93.95% for F1-score were obtained. Despite the hybrid logistic-based model achieving high accuracy, the unsatisfactory performance of stage estimation was noticed for iCS3 in the primary cohort (89.17%) and validation cohort (85.00%). Through bivariate logistic regression analysis, the posterior height of C4 (PH4) was further selected in the iCS3 to establish a corrected model, thus the evaluation metrics were upgraded to 95.83% and 90.00%, respectively.
CONCLUSIONS: An unbiased and objective assessment of the cervical vertebrae maturation (CVM) method can function as a decision-support tool, assisting in the evaluation of the optimal timing for treatment in growing adults. Our novel proposed logistic model yielded individual formulas for each specific CVM stage and attained exceptional performance, indicating the capability to function as a benchmark for maturity evaluation in clinical craniofacial orthopedics for Chinese female adolescents.

OBJECTIVE: To evaluate the size and shape of sella turcica and cranial base in patients with different degrees of congenital absence of teeth.
METHODS: The subjects comprised 322 patients from the Department of Orthodontics, West China Hospital of Stomatology, Sichuan University from 2020 to 2021. Based on the number of congenital absence of teeth, the patients were divided into three groups: control group (without loss of teeth, n=112), group Ⅰ (loss of 1-2 teeth, n=104), and group Ⅱ (loss of 3 or more teeth, n=106). Uceph cephalometric software was used to measure the linear and angular parameters of cranial base. The length, depth, and diameter of sella turcica were also calculated. The shape of sella turcica was described as normal or with aberrations. Analysis of variance, Kruskal-Wallis H test, chi-square test, and Fisher\'s exact test were conducted with SPSS 21.0.
RESULTS: No statistical differences were observed in the length, depth, and diameter of sella turcica and parameters related to the cranial base among the three groups (P>0.05). The incidence of sella turcica bridge among the three groups was statistically significant (P=0.013). The incidence was higher in the study group compared with the control group (P<0.05), and no significant difference was observed between groups Ⅰ and Ⅱ (P>0.05).
CONCLUSIONS: Although the linear size of sella turcica and parameters related to the cranial base was not statistically different between normal subjects and patients with congenital absence of teeth, the incidence of sella turcica bridge was higher in patients with congenital absence of teeth, suggesting the possibly abnormal anatomical morphology of sella turcica in this population.
目的: 探究不同程度恒牙先天缺失患者蝶鞍与颅底的大小及形态差异。方法: 选取2020—2021年就诊于四川大学华西口腔医院正畸科的322例患者为研究对象，依据先天缺牙数目将患者分为3组：对照组（无恒牙先天缺失，112例）；试验Ⅰ组（先天缺失1~2颗恒牙，104例）；试验Ⅱ组（先天缺失3颗及以上恒牙，106例）。使用Uceph头影测量软件对每位患者头颅侧位片的蝶鞍的长度、深度和直径以及颅底相关线性和角度参数进行测量。对每位患者的蝶鞍形态进行判定。采用SPSS 21.0软件对数据进行统计学分析。结果: 3组的蝶鞍长度、深度、直径以及颅底相关的线性和角度参数差异均无统计学意义（P>0.05）。3组的鞍桥发生率的差异有统计学意义（P=0.013），试验组高于对照组（P<0.05），试验Ⅰ组和试验Ⅱ组差异无统计学意义（P>0.05）。结论: 虽然蝶鞍的线性大小及颅底特征在正常人和先天缺牙患者中未见明显差异，但在先天缺牙患者中鞍桥发生率更高，提示该人群的蝶鞍解剖学形态可能异常。.

OBJECTIVE: Skeletal class II malocclusion is one of the most common malocclusions. Among the functional appliances for skeletal class II malocclusion, the Twin-Block appliance with a maxillary expander is effective in repositioning the mandible forward. In this study, we focused our efforts on investigating the effects of Twin-Block appliances with maxillary expanders on the upper airway in growing children with skeletal class II malocclusion by tracing and measuring lateral cephalograms after evaluating the consistency of three-dimensional CBCT data and two-dimensional lateral cephalogram data.
METHODS: A total of 102 patients ranging from 9 to 15 years old (11.37 ± 2.80, male/female ratio = 1:1) with skeletal class II malocclusion were selected to evaluate the consistency of CBCT data and lateral cephalogram data. The strongly and moderately correlated segments were then selected to study the effects of Twin-Block with a maxillary expander on the upper airway in 66 growing children with skeletal class II malocclusion (11.31 ± 1.23 years old, male/female ratio = 1:1) by lateral cephalograms.
RESULTS: The results showed a strong significant correlation in the nasopharynx (r = 0.708) and moderate significant correlations in the overall upper airway (r = 0.641), palatopharynx (r = 0.553), and glossopharynx (r = 0.575) but a weak correlation in the hypopharynx (r = 0.323). The corresponding determination coefficient (R2) was also determined by scatter plot analysis. Moreover, compared with the pretreatment data (T1), the total area of the upper airway and the areas of the nasopharynx, palatopharynx, and glossopharynx after functional treatment (T2) increased statistically and significantly.
CONCLUSIONS: Lateral cephalograms can reflect the volume of the nasopharynx and oropharynx in skeletal class II children to a certain extent, while Twin-Block appliances with maxillary expanders can widen the volume of the nasopharynx and oropharynx significantly.
CONCLUSIONS: The lateral cephalogram is reliable for analyzing the nasopharynx, palatopharynx, and glossopharynx in orthodontic clinical practice. Twin-Block appliances with maxillary expanders have a positive effect on skeletal class II patients with airway stenosis.

To analyze the diagnostic value of the tonsil-oropharynx (T/O) ratio on lateral cephalograms for evaluating tonsillar hypertrophy (TH).
A cross-sectional study was performed on 185 consecutive children (101 males, 84 females; mean age 7.3 ± 1.4 years) seeking orthodontic treatment. The T/O ratios on lateral cephalograms were calculated following Baroni et al.\'s method. Tonsil sizes were clinically determined according to the Brodsky grading scale. Spearman correlation coefficients between the T/O ratio and clinical tonsil size were calculated with the total sample and subgroups and then compared between subgroups. Diagnostic value was analyzed using the receiver operating characteristic (ROC) curve, sensitivity, specificity, positive and negative predictive values, and accuracy.
There was a strong correlation between the T/O ratio and clinical tonsil size in children (ρ = 0.73; P < 0.001). A significantly higher correlation coefficient was found in the Class III children. The ROC curve revealed an area under the curve of 0.90 (95% CI, 0.86-0.94; P < 0.001). The optimal cutoff value of the T/O ratio for predicting TH was 0.58, with a sensitivity of 98.7% and specificity of 64.2%. Employing the cutoff value of 0.5, the sensitivity was 100% and the specificity was 45.9%.
Measurement of the T/O ratio on lateral cephalograms may be helpful to initial screening in children for TH. Practitioners may combine the clinical examination of tonsil size with the cephalometric findings for a more comprehensive evaluation.

Many scholars have proven cervical vertebral maturation (CVM) method can predict the growth and development and assist in choosing the best time for treatment. However, assessing CVM is a complex process. The experience and seniority of the clinicians have an enormous impact on judgment. This study aims to establish a fully automated, high-accuracy CVM assessment system called the psc-CVM assessment system, based on deep learning, to provide valuable reference information for the growth period determination.
This study used 10,200 lateral cephalograms as the data set (7111 in train set, 1544 in validation set and 1545 in test set) to train the system. The psc-CVM assessment system is designed as three parts with different roles, each operating in a specific order. 1) Position Network for locating the position of cervical vertebrae; 2) Shape Recognition Network for recognizing and extracting the shapes of cervical vertebrae; and 3) CVM Assessment Network for assessing CVM according to the shapes of cervical vertebrae. Statistical analysis was conducted to detect the performance of the system and the agreement of CVM assessment between the system and the expert panel. Heat maps were analyzed to understand better what the system had learned. The area of the third (C3), fourth (C4) cervical vertebrae and the lower edge of second (C2) cervical vertebrae were activated when the system was assessing the images.
The system has achieved good performance for CVM assessment with an average AUC (the area under the curve) of 0.94 and total accuracy of 70.42%, as evaluated on the test set. The Cohen\'s Kappa between the system and the expert panel is 0.645. The weighted Kappa between the system and the expert panel is 0.844. The overall ICC between the psc-CVM assessment system and the expert panel was 0.946. The F1 score rank for the psc-CVM assessment system was: CVS (cervical vertebral maturation stage) 6 > CVS1 > CVS4 > CVS5 > CVS3 > CVS2.
The results showed that the psc-CVM assessment system achieved high accuracy in CVM assessment. The system in this study was significantly consistent with expert panels in CVM assessment, indicating that the system can be used as an efficient, accurate, and stable diagnostic aid to provide a clinical aid for determining growth and developmental stages by CVM.

Adenoid hypertrophy among orthodontic patients may be detected in lateral cephalograms. The study investigates the aerodynamic characteristics within the upper airway (UA) by means of computational fluid dynamics (CFD) simulation. Furthermore, airflow features are compared between subgroups according to the adenoidal nasopharyngeal (AN) ratios.
This retrospective study included thirty-five patients aged 9-15 years having both lateral cephalogram and cone beam computed tomography (CBCT) imaging that covered the UA region. The cases were divided into two subgroups according to the AN ratios measured on the lateral cephalograms: Group 1 with an AN ratio < 0.6 and Group 2 with an AN ratio ≥ 0.6. Based on the CBCT images, segmented UA models were created and the aerodynamic characteristics at inspiration and expiration were simulated by the CFD method for the two groups. The studied aerodynamic parameters were pressure drop (ΔP), maximum midsagittal velocity (Vms), maximum wall shear stress (Pws), and minimum wall static pressure (Pw).
The maximum Vms exhibits nearly 30% increases in Group 2 at both inspiration (p = 0.013) and expiration (p = 0.045) compared to Group 1. For the other aerodynamic parameters such as ΔP, the maximum Pws, and minimum Pw, no significant difference is found between the two groups.
The maximum Vms seems to be the most sensitive aerodynamic parameter for the groups of cases. An AN ratio of more than 0.6 measured on a lateral cephalogram may associate with a noticeably increased maximum Vms, which could assist clinicians in estimating the airflow features in the UA.

In the design of dental multifunctional Cone Beam Computed Tomography, the linear scanning strategy not only saves equipment cost, but also avoids the demand for patients to be repositioned when acquiring lateral cranial sequence images. In order to obtain panoramic images, we propose a local normalized cross-correlation stitching algorithm based on Gaussian Mixture Model. Firstly, the Block-Matching and 3D filtering algorithm is used to remove quantum and impulse noises according to the characteristics of X-ray images; Then, the segmentation of the irrelevant region and the extraction of the region of interest are performed by Gaussian Mixture Model; The locally normalized cross-relation is used to complete the registration with the multi-resolution strategy based on wavelet transform and Particle Swarm Optimization algorithm; Finally, image fusion is achieved by the weighted smoothing fusion algorithm. The experimental results show that the panoramic image obtained by this method has significant performance in both subjective vision and objective quality evaluation and can be applied to preoperative diagnosis of clinical dental deformity and postoperative effect evaluation.

Objective:To investigate the difference of lateral cephalogram, PSG, BMI in Uygur and Han OSAHS male patients. Method:OSAHS male patients with 33 Uygur cases and 42 Han cases,30 normal Uygur cases and 36 normal Han cases were taken as control.Lateral cephalogram of upright position in waking state, then comparecraniofacial strcture parameters and PSG dates, etc. Result:Patients in OSAHS group and normal group had significant differences in the MP-H, PAS, PNS-P, BMI (P<0.05), the Uygur healthy men and Uygur male OSAHS patients had significant difference in the ANB° (P<0.05). The difference was statistically significant in PNS-P, MP-H and BMI in Uygur and Han OSAHS male patients (P<0.05). Conclusion:The differences in airway plane, hyoid position and length of soft palate and weight were significantly different between healthy men and OSAHS men. Han OSAHS male patients and Uygur male patients had significant differences in Hyoid position, length of the soft palate and weight. Lateral cephalogram can judge blocking site of upper airway and provide opration plan.

OBJECTIVE: Velopharyngeal closure is an important physiological process contributing to the normal function of speech and swallowing. The aim of this study was to analyze the influence of sound intensity on velopharyngeal function in normal individuals.
METHODS: Lateral cephalograms of 38 volunteers obtained at rest and during phonation of vowel /i:/ at both high and low sound intensity were carefully analyzed. The digital sound level meter was used to evaluate and record the sound intensity of the phonation process. The angular and linear parameters on the lateral cephalograms were then measured to reveal the correlation between sound intensity and velopharyngeal closure.
RESULTS: All the angular parameter values measured in the study were significantly greater in high sound intensity condition. As for linear parameters, all values were found to be significantly larger at high sound intensity, except for the effective velopharyngeal length and the vertical velopharyngeal length. A multiple linear regression model was set up to describe the correlation between the sound intensity, the effective velopharyngeal length, and velopharyngeal closure. With the increase of sound intensity and the decrease of the effective velopharyngeal length, the width of velopharyngeal closure is enlarged.
CONCLUSIONS: As one of the characteristic features of sound wave, the sound intensity was found to affect the objectively measured parameters of velopharyngeal closure on lateral cephalograms.