ddPCR provides a sensitive test compared with GeneXpert MTB/RIF and mNGS for suspected Mycobacterium tuberculosis infection.

Introduction: The Metagenomics next-generation sequencing (mNGS) and GeneXpert MTB/RIF assay (Xpert) exhibited a sensitivity for tuberculosis (TB) diagnostic performance. Research that directly compared the clinical performance of ddPCR analysis, mNGS, and Xpert in mycobacterium tuberculosis complex (MTB) infection has not been conducted. Methods: The study aimed to evaluate the diagnostic performance of ddPCR compared to mNGS and Xpert for the detection of MTB in multiple types of clinical samples. The final clinical diagnosis was used as the reference standard. Results: Out of 236 patients with suspected active TB infection, 217 underwent synchronous testing for tuberculosis using ddPCR, Xpert, and mNGS on direct clinical samples. During follow-up, 100 out of 217 participants were diagnosed with MTB infection. Compared to the clinical final diagnosis, ddPCR produced the highest sensitivity of 99% compared with mNGS (86%) and Xpert (64%) for all active MTB cases. Discussion: Twenty-two Xpert-negative samples were positive in mNGS tests, which confirmed the clinical diagnosis results from ddPCR and clinical manifestation, radiologic findings. Thirteen mNGS-negative samples were positive in ddPCR assays, which confirmed the clinical final diagnosis.ddPCR provides a higher sensitive compared to Xpert and mNGS for MTB diagnosis, as defined by the high concordance between ddPCR assay and clinical final diagnosis.

Secondary Infection Surveillance with Metagenomic Next-Generation Sequencing in COVID-19 Patients: A Cross-Sectional Study.

Background: Metagenomic next-generation sequencing (mNGS) is a promising tool for improving antimicrobial therapy and infection control decision-making in complex infections. Secondary infection surveillance using mNGS in COVID-19 patients has rarely been reported. Methods: Respiratory pathogen and antibiotic resistance prediction were evaluated by BALF mNGS for 192 hospitalized COVID-19 patients between December 2022 and February 2023. Results: Secondary infection was confirmed in 83.3% (160/192) of the COVID-19 patients, with bacterial infections (45%, 72/160) predominating, followed by mixed bacterial and fungal infections (20%, 32/160), and fungal infections (17.5%, 28/160). The incidence of bacterial or viral secondary infection was significantly higher in patients who were admitted to the ICU, received mechanical ventilation, or developed severe pneumonia (all p<0.05). Klebsiella pneumoniae (n=30, 8.4%) was the most prevalent pathogen associated with secondary infection followed by Acinetobacter baumannii (n=29, 8.1%), Candida albicans (n=29, 8.1%), Aspergillus fumigatus (n=27, 7.6%), human herpes simplex virus type 1 (n=23, 6.4%), Staphylococcus aureus (n=20, 5.6%) and Pneumocystis jiroveci (n=14, 3.9%). The overall concordance between the resistance genes detected by mNGS and the reported phenotypic resistance in 69 samples containing five clinically important pathogens (ie, K. pneumoniae, A. baumannii, S. aureus, P. aeruginosa and E. coli) that caused secondary infection was 85.5% (59/69). Conclusion: mNGS can detect pathogens causing secondary infection and predict antimicrobial resistance for COVID19 patients. This is crucial for initiating targeted treatment and rapidly detect unsuspected spread of multidrug-resistant pathogens.

The psc-CVM assessment system: A three-stage type system for CVM assessment based on deep learning.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Dynamic associations between the respiratory tract and gut antibiotic resistome of patients with COVID-19 and its prediction power for disease severity.

The antibiotic resistome is the collection of all antibiotic resistance genes (ARGs) present in an individual. Whether an individual's susceptibility to infection and the eventual severity of coronavirus disease 2019 (COVID-19) is influenced by their respiratory tract antibiotic resistome is unknown. Additionally, whether a relationship exists between the respiratory tract and gut ARGs composition has not been fully explored. We recruited 66 patients with COVID-19 at three disease stages (admission, progression, and recovery) and conducted a metagenome sequencing analysis of 143 sputum and 97 fecal samples obtained from them. Respiratory tract, gut metagenomes, and peripheral blood mononuclear cell (PBMC) transcriptomes are analyzed to compare the gut and respiratory tract ARGs of intensive care unit (ICU) and non-ICU (nICU) patients and determine relationships between ARGs and immune response. Among the respiratory tract ARGs, we found that Aminoglycoside, Multidrug, and Vancomycin are increased in ICU patients compared with nICU patients. In the gut, we found that Multidrug, Vancomycin, and Fosmidomycin were increased in ICU patients. We discovered that the relative abundances of Multidrug were significantly correlated with clinical indices, and there was a significantly positive correlation between ARGs and microbiota in the respiratory tract and gut. We found that immune-related pathways in PBMC were enhanced, and they were correlated with Multidrug, Vancomycin, and Tetracycline ARGs. Based on the ARG types, we built a respiratory tract-gut ARG combined random-forest classifier to distinguish ICU COVID-19 patients from nICU patients with an AUC of 0.969. Cumulatively, our findings provide some of the first insights into the dynamic alterations of respiratory tract and gut antibiotic resistome in the progression of COVID-19 and disease severity. They also provide a better understanding of how this disease affects different cohorts of patients. As such, these findings should contribute to better diagnosis and treatment scenarios.

Treatment of skeletal class III malocclusion using a combined clear aligner and surgery-early approach : Assessment based on the American Board of Orthodontics Objective Grading System.

PURPOSE: To evaluate whether clear aligner therapy (CAT) combined with a surgery-early approach can achieve good therapeutic effects in patients with skeletal class III malocclusion. METHODS: Thirty consecutive skeletal class III malocclusion cases treated with clear aligners combined with early surgery were selected. Treatment time, lateral cephalograms and American Board of Orthodontics Objective Grading System (ABO-OGS) scores of the treatment models were measured to evaluate the treatment efficiency, facial profile, and occlusion. RESULTS: The results showed that early surgery was achieved after 7.71 months of presurgical orthodontics, on average. ANB decreased by 5.57° (P < 0.001), and STissue N Vert to Pog' decreased by 7.29 mm (P = 0.001), both reaching normal values. The posttreatment ABO-OGS scores were 26.600 on average, meeting its standards. CONCLUSIONS: With the assistance of CAT, early surgery can be accomplished in patients with skeletal class III malocclusion, improving their facial profile and achieving functional occlusion.

The Real-World Clinical Impact of Plasma mNGS Testing: an Observational Study.

Plasma metagenomic next-generation sequencing (mNGS) testing is a promising diagnostic modality for infectious diseases, but its real-world clinical impact is poorly understood. We reviewed patients who had undergone plasma mNGS at a general hospital to evaluate the clinical utility of plasma mNGS testing. A total of 76.9% (113/147) of plasma mNGS tests had a positive result. A total of 196 microorganisms (58) were identified and reported, of which 75.6% (148/196) were clinically relevant. The median stringent mapped read number (SMRN) of clinically relevant organisms was 88 versus 22 for irrelevant organisms (P = 0.04). Based on the clinically adjudicated diagnosis, the positive and negative percent agreements of plasma mNGS testing for identifying a clinically defined infection were 95.2% and 67.4%, respectively. The plasma mNGS results led to a positive impact in 83 (57.1%) patients by diagnosing or ruling out infection and initiating targeted therapy. However, only 32.4% (11/34) of negative mNGS tests showed a positive impact, suggesting that plasma mNGS testing alone may not be a powerful tool to rule out infection in clinical practice. In the subset of 37 patients positive for both plasma mNGS and conventional testing, mNGS identified the pathogen(s) 2 days (IQR = 0.75 to 4.25) earlier than conventional testing. mNGS enables pathogen identification within 24 h, but given that the detection of clinically irrelevant organisms and nearly half of the tests result in no or a negative clinical impact, more clinical practice and studies are required to better understand who and when to test and how to optimally integrate mNGS into the infectious disease diagnostic workup. IMPORTANCE In this study, we show that although plasma mNGS testing significantly improved the detection rate of tested samples, nearly one in four (24.5%, 48/196) mNGS tests reported organisms were not clinically relevant, emphasizing the importance of cautious interpretation and infectious disease consultation. Moreover, based on clinical adjudication, plasma mNGS testing resulted in no or a negative impact in nearly half (43.5%, 64/147) of patients in the current study, indicating that how best to integrate this advanced method into current infectious disease diagnostic frameworks to maximize its clinical utility in real-world practice is an important question. Therefore, recommending plasma mNGS testing as a routine supplement to first-line diagnostic tests for infectious diseases faces great challenges. The decision to conduct mNGS testing should take into account the diagnostic performance, turnaround time and cost-effectiveness of mNGS, as well as the availability of conventional tests.

[Comparison of clear aligners and customized lingual appliance for bimaxillary dentoalveolar protrusion: a retrospective study].

PURPOSE: To compare the treatment effects of clear aligners and customized lingual appliance on treating bimaxillary dentoalveolar protrusion patients with first premolar extractions. METHODS: Fifty-four patients with bimaxillary dentoalveolar protrusion treated in Shanghai Ninth People Hospital were involved in the retrospective study. Twenty-five cases used clear aligners and 29 cases used customized lingual appliance. All of them were treated by extracting 4 first premolars and retracting anterior teeth with strong anchorage. The changes of anterior tooth and soft tissue adduction before and after treatment were compared by lateral cephalometric measurements. SPSS 26.0 software package was used for data analysis. RESULTS: The total course of treatment in the clear aligners group (46.32±7.37 months) was about 10.8 months longer than that in the customized lingual appliance group (35.55±5.90 months) (P＜0.05). There was no significant difference in upper incisor retraction, lower incisor inclination and overjet reduction between the two groups(P＞0.05). There were significant differences in upper lip retraction, lower lip retraction, upper incisor torque reduction, and overbite reduction between the two groups(P＜0.05). Customized lingual appliance group showed a significant improvement of lips retraction and overbite reduction in orthodontic treatment. For the correction of overjet, there was no significant difference between the two groups (P=0.337). The data of U1-OP (the distance between edge of the upper central incisor and the functional occlusal plane) was not in normal distribution, and there was no significant difference between the two groups(P=0.184). CONCLUSIONS: The two techniques can both retract the anterior teeth and lips to improve the profile. However, the customized lingual appliance was more effective in improving the soft tissue profile of patients with bimaxillary dentoalveolar protrusion, with shorter treatment course.

Dynamic Alterations in the Respiratory Tract Microbiota of Patients with COVID-19 and its Association with Microbiota in the Gut.

The role of respiratory tract microbes and the relationship between respiratory tract and gut microbiomes in coronavirus disease 2019 (COVID-19) remain uncertain. Here, the metagenomes of sputum and fecal samples from 66 patients with COVID-19 at three stages of disease progression are sequenced. Respiratory tract, gut microbiome, and peripheral blood mononuclear cell (PBMC) samples are analyzed to compare the gut and respiratory tract microbiota of intensive care unit (ICU) and non-ICU (nICU) patients and determine relationships between respiratory tract microbiome and immune response. In the respiratory tract, significantly fewer Streptococcus, Actinomyces, Atopobium, and Bacteroides are found in ICU than in nICU patients, while Enterococcus and Candida increase. In the gut, significantly fewer Bacteroides are found in ICU patients, while Enterococcus increases. Significant positive correlations exist between relative microbiota abundances in the respiratory tract and gut. Defensin-related pathways in PBMCs are enhanced, and respiratory tract Streptococcus is reduced in patients with COVID-19. A respiratory tract-gut microbiota model identifies respiratory tract Streptococcus and Atopobium as the most prominent biomarkers distinguishing between ICU and nICU patients. The findings provide insight into the respiratory tract and gut microbial dynamics during COVID-19 progression, considering disease severity, potentially contributing to diagnosis, and treatment strategies.

Effects of the advanced mandibular spring on mandibular retrognathia treatment: a three-dimensional finite element study.

BACKGROUND: The Advanced Mandibular Spring (AMS) was newly developed as a dentofacial orthopedic appliance in conjunctive use of clear aligners to treat Class II malocclusion with mandibular retrognathia in adolescents. This study aimed to launch a biomechanical assessment and evaluate whether the stress patterns generated by AMS promote mandibular growth. METHODS: A three-dimensional finite element model was constructed using images of CBCT and spiral CT. The model consisted of craniomaxillofacial bones, articular discs, retrodiscal elastic stratum, masticatory muscle, teeth, periodontal ligament, aligner and AMS. Mechanical effects were analyzed in three types of models: mandibular postural position, mandibular advancement with AMS, and mandibular advancement with only muscular force. RESULTS: The stress generated by AMS was distributed to all teeth and periodontal ligament, pushing mandibular teeth forward and maxillary teeth backward. In the temporomandibular joint area, the pressure in the superior and posterior aspects of the condyle was reduced, which conformed to the stress pattern promoting condylar and mandibular growth. Stress distribution became even in the anterior aspect of the condyle and the articular disc. Significant tensile stress was generated in the posterior aspect of the glenoid fossa, which conformed to the stress pattern stimulating the remodeling of the fossa. CONCLUSIONS: AMS created a favorable biomechanical environment for treating mandibular retrognathia in adolescents.

Accuracy of dental arch form in customized fixed labial orthodontic appliances.

INTRODUCTION: This study evaluated arch form accuracy with or without premolar extraction in customized fixed labial orthodontic appliance treatment. METHODS: Setup and posttreatment digital models of 27 samples (15 extractions and 12 nonextractions) were selected and superimposed by best-fit surface-based registration in both the maxilla and the mandible. The facial axis points were identified and converted into Cartesian coordinates. A sixth-order polynomial equation was used to fit dental arches. Arch discrepancies (the mean distance between 2 arch forms) and similarities were compared between extraction and nonextraction groups, maxilla and mandible, and anterior and posterior arches. RESULTS: The arch discrepancy between extraction and nonextraction groups showed no statistically significant difference, but a statistically significant difference in arch similarity was found in the mandible. There were statistically significant differences between anterior and posterior arch discrepancies in the extraction (mandible) and the nonextraction (maxilla and mandible) groups. However, no statistically significant correlation was shown between anterior and posterior arch discrepancies. The arch similarities were 96.18% and 97.38% in the maxilla and 96.01% and 97.49% in the mandible between extraction and nonextraction groups. Arch form discrepancies and similarities showed a moderate correlation but no statistically significant differences between the maxilla and the mandible. CONCLUSIONS: In customized fixed labial orthodontic appliance treatment, arch form setup can be accurately achieved with and without premolar extraction. Anterior arch form acquires fewer discrepancies than the posterior arch, and overcorrection should be added to the end of the customized archwire to reduce posterior arch discrepancies. The discrepancy of the maxillary and mandibular arches is interrelated, and adjustments should be made on both maxillary and mandibular archwires to correct single-jaw transverse malposition.

[In vitro study of a new lasso device for intra-canal broken instrument removal].

PURPOSE: To collect facial stereo images of different lip protrusion by using three dimensional surface imaging device, and investigate facial aesthetic evaluation and differences between orthodontists, general dentists and laypeople. METHODS: In this study, one college student was recruited to take a three-dimensional image of the natural head and face. The software was simulated with a gradient of 2 mm to make the soft tissue lips move back and forth along the sagittal axis from the VSL line.The movement limit was 6 mm in front of and behind the VSL line. The observers included orthodontists, general dentists and laypeople. The data were analyzed with SAS 9.4 software package,visual analog scoring (VAS) was used for evaluation, and fixed-effect model was used for statistical analysis. RESULTS: The results showed that when the lip was on the VSL line, it got the highest scores amount all three groups and had no significant difference.When the lip became protrusive or retractive, it had negative impact on facial esthetics. There were significant differences in the scores of three groups in every 2mm of lip protrusion and lip retraction(P＜0.05). VAS 5 points or less were used as the unacceptable facial aesthetic score. The results showed that lip protrusion was 4 mm before the VSL line in the orthodontist group and less than 5 in the laypeople group . When the lip protruded 6mm before the VSL line and retracted 4 mm behind the VSL line, the scores of the three groups were lower than 5 points. The results also showed that male evaluation of lip protrusion 2 mm before the VSL line had a lower score than female; On the other hand, female evaluation of lip retraction behind the VSL line above 4mm had a lower score than male. CONCLUSIONS: Lip position has significant effect on facial aesthetics. Different observers had significant differences in the evaluation of lip position on facial aesthetics. It is suggested that orthodontists need more communication with patients in determining the target position of orthodontic treatment to improve treatment satisfaction.

Accuracy of different tooth surfaces on 3D printed dental models: orthodontic perspective.

BACKGROUND: Few studies have been reported regarding the accuracy of 3D-printed models for orthodontic applications. The aim of this study was to assess the accuracy of 3D-printed dental models of different tooth surfaces. METHODS: Thirty volunteers were recruited from the hospital, and then their dental models were produced by means of oral scanning and a stereolithography-based 3D printer. Each printed model was digitally scanned and compared with the oral-scanned STL file via superimposition analysis. A color map was used to assess the accuracy of different surfaces (occlusal, buccal, lingual) of anterior and posterior teeth. The Tukey test was used to evaluate the differences between the superimposition. RESULTS: Statistically significant differences were found in the average deviations of different tooth surfaces (P < 0.05). The mean average absolute deviations of the occlusal surfaces of posterior teeth were greater than those of other surfaces. Percentages of points beyond the upper and lower limits of different tooth surfaces displayed the same results (P < 0.05). CONCLUSIONS: Occlusal surfaces, especially pits and fissures of posterior teeth on 3D printed maxillary dental models, showed greater distortions than those of other teeth and regions.

Assessing the Influence of Chin Asymmetry on Perceived Facial Esthetics With 3-Dimensional Images.

PURPOSE: We used 3-dimensinonal (3D) images to assess the influence of chin asymmetry on perceived facial esthetics, investigate the cognitive boundaries of chin asymmetry among orthodontists, general dentists, and laypersons, and provide quantitative reference for clinical treatment. MATERIALS AND METHODS: A 3D facial image was obtained using the 3dMD imaging system (3dMD, Atlanta, GA). The chin was altered in 2-mm increments from 0 to 12 mm and to the left and right using the software program. These images were rated by 66 orthodontists, 89 general dentists, and 66 laypersons as 1) chin symmetry; 2) slight chin asymmetry but acceptable; and 3) serious asymmetry and treatment needed. Multivariate mixed linear regression and multivariate mixed logistic regression analyses were used for statistical data analysis. Descriptive and bivariate statistics were calculated, and statistical significance was considered present at P = .05. RESULTS: The observers progressively increased the grade ratings and the desire for surgery for greater asymmetries (P < .001). Orthodontists and general dentists could perceive a chin deviation of 4 mm to the right and 2 mm to the left, with 8-mm deviation considered to require treatment. Laypersons had a clear perception of a 4-mm chin deviation, with 8 mm to the right and 10 mm to the left considered to require treatment. The right chin deflection was more easily perceived than was the left (P < .05). CONCLUSIONS: Chin asymmetry has a great influence on facial esthetics. We found a statistically significant difference between clinicians (orthodontists and general dentists) and laypersons in the cognition of chin asymmetry and the recommendations for treatment.

Accuracy of in vitro mandibular volumetric measurements from CBCT of different voxel sizes with different segmentation threshold settings.

BACKGROUND: To determine the accuracy of volumetric measurements of the mandible in vitro by cone-beam computed tomography (CBCT) and to analyze the influence of voxel sizes and segmentation threshold settings on it. METHODS: The samples were obtained from pig mandibles and scanned with 4 voxel sizes: .125 mm, .20 mm, .30 mm, and .40 mm. The minimum segmentation thresholds in Hounsfield units (HU) were set as 0, 100, 200, 300, and 400, respectively, for each voxel size for 3D reconstruction. Laser scanning as the reference, the volumes of each CBCT scanning, the mean iterative distances of superimposition and total positive and negative deviations were recorded and compared. RESULTS: The volumes of CBCT-scan deviated from those of laser-scan by + 7.67% to - 3.05% with different HU and voxel sizes. The deviation increased with the voxel size. There was a more suitable minimum HU threshold of segmentation (HU100 for .125 mm, 200 for .20 mm, 300 for .30 mm, and 400 for .40 mm) for each voxel size. CONCLUSIONS: Voxel sizes and Hounsfield unit thresholds influence the accuracy of volumetric measurements in CBCT scanning. The volume increase with the voxel size, and different voxel sizes correspond to different optimal Hounsfield unit thresholds.

Detection of alveolar bone defects with three different voxel sizes of cone-beam computed tomography: an in vitro study.

This study was conducted to assess the accuracy of cone-beam computed tomography (CBCT) of different voxel sizes in the detection of alveolar bone defects, and to select the optimal voxel size for clinical use. 46 in-vitro teeth were placed in bovine ribs in which alveolar bone defects were randomly simulated. In total, 32 alveolar bone defects and 14 teeth without periodontal defects were used. CBCT images were acquired with the use of three different voxel sizes: 0.125-mm, 0.2-mm and 0.4-mm. The scan data were 3D-reconstructed in Mimics software and evaluated by two observers with more than 5 years of experience in CBCT. Receiver operating characteristic (ROC) curves and diagnostic values were obtained. Pairwise comparison of ROC curves was made for evaluation of the diagnostic values of different voxel sizes. Kappa statistics assessed the observer reliability. Results were considered significant at P < 0.05. It showed no statistically significant difference between 0.125-mm group and 0.2-mm group, but 0.4-mm group had lower Az values that differed significantly from 0.125-mm and 0.2-mm groups (P < 0.05). Based on diagnostic value and radiation protection, 0.2-mm voxel size may be a good choice for the detection of bone defects with CBCT.

Hemifacial microsomia treated with a hybrid technique combining distraction osteogenesis and a mandible-guided functional appliance: Pilot study.

INTRODUCTION: The purpose of this study was to evaluate the therapeutic effect of a hybrid treatment for hemifacial microsomia that combines distraction osteogenesis and a mandible-guided functional appliance to correct mandibular asymmetry. METHODS: This was a retrospective analysis of 10 patients with unilateral hemifacial microsomia who underwent mandibular ramus distraction osteogenesis in our hospital from February 2013 to July 2015. The cases were classified into 2 comparison groups: 5 patients were in the MG-DO group (distraction osteogenesis combined with an mandible-guided functional appliance) and 5 in the control group (distraction osteogenesis only). Anteroposterior cephalometric analyses were conducted before and after treatment. Soft tissue symmetry and the occlusal relationship were observed from facial and intraoral photographs. Statistical analyses were performed to determine changes between before and after treatment as well as intergroup differences. RESULTS: The MG-DO group showed greater vertical elongation of the mandibular ramus and less overcorrection and mandibular deviation than the control group. Occlusal reconstruction was enabled by the mandible-guided functional appliance owing to a decrease in lateral shifting. The symmetry of both skeletal and soft tissues was significantly improved in the MG-DO group. CONCLUSIONS: The hybrid technique combining distraction osteogenesis and the mandible-guided functional appliance proved to be effective in correcting canting and deviation during mandibular elongation, which improved facial symmetry and occlusal balance in patients with hemifacial microsomia.

Precision of 3D-printed splints with different dental model offsets.

INTRODUCTION: The purpose of this study was to assess the precision of 3D-printed splints generated from different dental model offsets. METHODS: Ten maxillary models were offset by given distances (0.05 mm, 0.1 mm, and 0.2 mm). Digital splints were created by means of the boolean operation. The physical splints were fabricated by means of digital light-processing (DLP) rapid prototyping technologies. A layer of impression material, which could be weighed by means of an electronic analytical balance, was placed in the airspace between the splint and the teeth. We also calculated the shell-to-shell deviations by measuring the 3-dimensional (3D) euclidean distances between the surface points of the scanned splints and the original digital splint and evaluating the results with color-mapping methods. RESULTS: There was a statistically significant difference in the amounts of impression material remaining in the airspace between the 0.0-mm group and the 0.05-mm, 0.1-mm, and 0.2-mm groups (P < 0.05), between the 0.05-mm and the 0.1-mm and 0.2-mm groups (P < 0.05), and between the 0.0-mm group and the 0.05-mm, 0.1-mm, and 0.2-mm groups (P < 0.05). There was a statistically significant difference in shell-to-shell deviations between the 0.05-mm and the 0.1-mm and 0.2-mm groups (P < 0.05). CONCLUSIONS: 3D-printed splints generated from offset dental models (offset 0.05 mm, 0.1 mm, and 0.2 mm) can fit better on the teeth than splints from no-offset dental models. An offset of 0.1 mm is the best choice of parameter for generating the splint.

Changes of alveolar bone dehiscence and fenestration after augmented corticotomy-assisted orthodontic treatment: a CBCT evaluation.

BACKGROUND: To evaluate the changes of alveolar dehiscence and fenestration after augmented corticotomy-assisted orthodontic treatment on cone-beam computed tomography (CBCT) compared with traditional pre-surgical orthodontics, both quantitatively and qualitatively. METHODS: Two hundred and four anterior teeth from 17 skeletal class III malocclusions were divided into four groups. Groups G1 (upper teeth) and G3 (lower teeth), comprising 120 teeth, accepted traditional pre-surgical orthodontics; groups G2 (upper teeth) and G4(lower teeth), comprising 84 teeth, accepted augmented corticotomy-assisted pre-surgical orthodontics. The changes of alveolar bone dehiscence and fenestration of each tooth in all groups were evaluated with the help of CBCT. RESULTS: Quantitative analysis for comparing both groups: For the upper teeth, d1 - d0 was different between both groups while f1 - f0 was not statistically different. For the lower teeth, d1 - d0 was statistically different between both groups while f1 - f0 was not statistically different. Qualitative analysis: For the teeth that had no dehiscence before treatment, G2 and G4 had a better transition than did G1 and G3. For those having dehiscence before treatment, G4 had a better transition than did G3. For teeth having no fenestration before treatment, there was no statistically significant difference in transition between the control and treatment groups. For those having fenestration before treatment, G4 had a better transition than did G3. CONCLUSIONS: For skeletal class III patients, augmented corticotomy-assisted orthodontic treatment is a promising method of improving alveolar bone dehiscence and fenestration for lower anterior teeth, and it also has the potential to protect both lower and upper anterior teeth against dehiscence.

[Assessing the influence of chin prominence on perceived facial aesthetics among three groups of observers].

PURPOSE: To assess the influence of chin prominence on facial aesthetics with 3D images, to investigate the cognitive boundaries of chin prominence among orthodontists, general dentists and laypeople and compare the variance of their cognitive data, in order to provide quantitative reference for selection of clinical treatment. METHODS: A 3D facial image was obtained by 3dMD. The soft tissue pogonion point was altered in 2 mm increments from -10 to 10 mm with Geomagic Wrap 2015, in order to represent retrusion and protrusion of the chin. These images were rated by orthodontists, general dentists and laypeople with VAS scores. Multivariate mixed linear regression was used to analyze the influence of gender, age and chin prominence on VAS scores, and whether there were differences among different groups with SAS 9.4 software package. ANOVA was also applied for comparison of each prominence. RESULTS: This study was composed of 243 subjects, including 90 orthodontists, 101 general dentists and 52 laypeople. Chin prominence had significant effect on VAS scores. VAS scores decreased by 0.8910 for each unit increase in chin retrusion and decreased by 1.0958 for each unit increase in chin protrusion（P<0.01）. Desire for treatment started when chin retrusion exceeded 6 mm in orthodontist group and layperson group, 4 mm in general dentist group, and chin protrusion reached 6 mm in all groups（VAS scores <5）. There was no significant difference in the scores among orthodontists, general dentists and laypeople with the variance of chin prominence, and there was no significant difference in gender and age. CONCLUSIONS: Chin prominence had significant effect on facial aesthetics. Soft tissue pogonion point located on the zero meridian was considered as the most attractive. Treatment needs increased significantly when chin protrusion reached 6 mm or chin retrusion exceeded 6 mm. There was no significant difference in the assessment among orthodontists, general dentists and laypeople.

ADAM10 modulates SOX9 expression via N1ICD during chondrogenesis at the cranial base.

The cranial base is the foundation of the craniofacial structure, and any interruption of the cranial base can lead to facial deformity. The cranial base develops from two synchondroses via endochondral ossification. Chondrogenesis is an important step in endochondral ossification. A disintegrin and metalloprotease (ADAM) 10 participates in the Notch1 signalling pathway, which has been reported to regulate chondrogenesis via a SOX9-dependent mechanism. However, little is known about the function of ADAM10 in chondrogenesis. In this study, adam10-conditional-knockout (cKO) mice exhibited sharper naso-labial angles and flatter skulls than wild-type (WT) mice. In the sagittal plane, SOX9 was more widespread in the cranial base in Adam10-cKO mice than in WT mice. For in vitro experiments, we used the ATDC5 cell line as a model to investigate the role of ADAM10 in chondrogenesis. Plasmid 129 was designed to decrease the expression of Adam10; the resulting downregulation of Adam10 reduced the production of N1ICD. Plasmid 129 increased the expression of SOX9 under chondrogenic induction, and this increase could be inhibited by transfection with exogenous N1ICD. Collectively, these results show that ADAM10 participates in chondrogenesis by negatively regulating SOX9 expression in an N1ICD-dependent manner during cranial base development.