Changes in masseter muscle morphology after surgical-orthodontic treatment in patients with skeletal Class III malocclusion with mandibular asymmetry: The automatic masseter muscle segmentation model.

INTRODUCTION: This study evaluated the masseter muscle changes after surgical-orthodontic treatment in patients with a skeletal Class III malocclusion using automatic segmentation. METHODS: Images of 120 patients with skeletal Class III malocclusion were obtained and reconstructed at T0 (pretreatment), T1 (presurgery), and T2 (6-12-month postsurgery). The patients were divided into symmetrical and asymmetrical groups. The volume, major axis length, maximum cross-sectional area, horizontal cross-sectional area 5 mm above the mandibular foramen (CSAF), and orientation were calculated automatically. RESULTS: In the asymmetrical group, the volume and major axis length on the deviated side were lower than on the nondeviated side at T0, T1, and T2 (P <0.05). There were no significant differences in maximum cross-sectional area and CSAF bilaterally. The orientation was coronally more vertical and sagittally more forward on the deviated side (both P <0.001). In the symmetrical group, there were no significant bilateral differences at T0, T1, and T2. The volume, major axis length, and CSAF decreased, and the coronal orientation was more vertical on the nondeviated side at T2 than at T0 in both groups (P <0.05). The coronal plane orientation was more inclined on the deviated side at T2 than at T0 in the asymmetrical group (P <0.05). CONCLUSIONS: The smaller volume on the deviated side at T2 indicates the need for myofunctional training after surgery. The masseter muscle volume and the cross-sectional area did not recover to the preorthodontic levels. Studies with longer follow-up durations are needed to confirm these findings.

Early and 1-year postsurgical stability and its factors in patients with complicated skeletal Class â ¢ malocclusion treated by conventional and surgery-first approach: A prospective cohort study.

INTRODUCTION: This study aimed to compare postsurgical stability between conventional (CSA) and surgery-first (SFA) approaches and investigate its prognostic factors in patients with a skeletal Class Ⅲ extraction. METHODS: Twenty and 19 patients treated with LeFort I osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) with premolar extraction were enrolled in SFA and CSA groups, respectively. Serial cone-beam computed tomography images obtained before surgery, immediately after surgery (T1), 3 months after surgery, and 12 months after surgery were used for 3-dimensional quantitative analysis. The condyle was segmented for analyzing volumetric changes. Repeated measures analysis of variance, independent t test, and chi-square test were used to compare time-course and intergroup differences. Pearson and Kendall correlation and multivariate linear regression analyses were used to explore prognostic factors affecting skeletal stability. RESULTS: In both CSA and SFA, postsurgical relapse mainly occurred in the mandible sagittal and vertical dimensions and during the first 3 months after surgery. Stability in SFA was significantly less than that in CSA. Intraoperatively, inferolateral condylar displacement with proximal segment inwards, clockwise rotation, and return movements after surgery were observed regardless of the treatment approach. The condylar volume remained stable over time. Multivariate regression analysis showed that posterior vertical dimension (VD) at T1 (-1.63 mm), surgical amount of mandibular setback (-10.33 mm), surgical condylar downwards displacement (-1.28 mm), and anterior overjet at T1 (6.43 mm) were the most important predictors of early mandibular relapse (r2 = 0.593). CONCLUSIONS: The risk of early relapse could be reduced by controlling the anterior, middle, and posterior constraints provided by the prediction model.

On the open problem related to rank equalities for the sum of finitely many idempotent matrices and its applications.

Tian and Styan have shown many rank equalities for the sum of two and three idempotent matrices and pointed out that rank equalities for the sum P1 + ⋯+P k with P1,…, P k be idempotent (k > 3) are still open. In this paper, by using block Gaussian elimination, we obtained rank equalities for the sum of finitely many idempotent matrices and then solved the open problem mentioned above. Extensions to scalar-potent matrices and some related matrices are also included.

Bronchial lavage tNGS in the diagnosis of pulmonary tuberculosis.

BACKGROUND: Tuberculosis (TB), primarily caused by Mycobacterium tuberculosis, remains a significant global health concern. Targeted Next-Generation Sequencing (tNGS) has emerged as a rapid and comprehensive diagnostic tool for tuberculosis, offering advantages over traditional methods and serving as an effective alternative for drug susceptibility testing and the detection of drug-resistant tuberculosis. OBJECTIVE: This study aimed to retrospectively analyze the clinical characteristics of pulmonary tuberculosis patients. After explore the application value of targeted next-generation sequencing technology in this patient population, providing valuable insights for clinical diagnosis and treatment. METHODS: In this retrospective study, we analyzed data from 65 patients with laboratory-confirmed tuberculosis admitted to Tianjin Baodi Hospital from November 14, 2020, to February 1, 2023. Patients underwent bronchoalveolar lavage fluid (BALF) testing, including acid-fast staining, culture, and tNGS. Biopsies and histopathological examinations were performed on some patients, along with comprehensive radiological assessments for all. RESULTS: Among the 65 pulmonary tuberculosis patients, targeted next-generation sequencing detected pathogens in bronchoalveolar lavage fluid with a positivity rate of 93.8%, significantly higher than traditional methods such as acid-fast staining, culture, and pathology. Compared to bronchoalveolar lavage fluid smear, targeted next-generation sequencing demonstrated significantly higher diagnostic sensitivity (98.46% vs. 26.15%) and accuracy (98.46% vs. 26.15%). CONCLUSION: Targeted next-generation sequencing, with its high sensitivity and specificity compared to traditional methods, provides unique advantages in detecting pathogens among these patients, highlighting its importance in disease management.

Automatic Masseter Muscle Accurate Segmentation from CBCT Using Deep Learning-Based Model.

Segmentation of the masseter muscle (MM) on cone-beam computed tomography (CBCT) is challenging due to the lack of sufficient soft-tissue contrast. Moreover, manual segmentation is laborious and time-consuming. The purpose of this study was to propose a deep learning-based automatic approach to accurately segment the MM from CBCT under the refinement of high-quality paired computed tomography (CT). Fifty independent CBCT and 42 clinically hard-to-obtain paired CBCT and CT were manually annotated by two observers. A 3D U-shape network was carefully designed to segment the MM effectively. Manual annotations on CT were set as the ground truth. Additionally, an extra five CT and five CBCT auto-segmentation results were revised by one oral and maxillofacial anatomy expert to evaluate their clinical suitability. CBCT auto-segmentation results were comparable to the CT counterparts and significantly improved the similarity with the ground truth compared with manual annotations on CBCT. The automatic approach was more than 332 times shorter than that of a human operation. Only 0.52% of the manual revision fraction was required. This automatic model could simultaneously and accurately segment the MM structures on CBCT and CT, which can improve clinical efficiency and efficacy, and provide critical information for personalized treatment and long-term follow-up.