Effect of orthodontic treatment with premolar extractions on occlusal planes: A retrospective study.

OBJECTIVE: To figure out whether premolar extractions treatment would influence the cant of the occlusal planes and thus affect dentoskeletal patterns in patients with different types of malocclusions. MATERIALS AND METHODS: A total of 140 post-orthodontic treatment subjects (96 females, 44 males) were included in this study, and their lateral cephalograms and demographic information were collected and analysed. The patients were divided into extraction and non-extraction groups. The ANB, SNA, SNB, Wits, Facial Height Index (FHI), SN-MP, SN-AOP, SN-POP and AOP-POP angle were measured on the cephalograms. Other possible confounding factors were recorded. Data were analysed by univariate analysis, stratified analysis, multivariate analysis, and coefficient analysis. RESULTS: After treatment, the changes in the AOP-SN, POP-SN and AOP-POP angle were statistically different between the extraction and non-extraction groups. The results were consistent in different skeletal malocclusions and extent of crowding according to stratified analysis. After adjusting all confounding factors, the cant of the posterior occlusal plane was flattened further by 2.14 degrees in the extraction group than the non-extraction group after orthodontic treatment, and the AOP-SN and AOP-POP angle would further increase by 1.72 and 3.81 degrees, respectively. Although no significant differences were found between the two groups, the SNA, ANB, and Wits in the extraction group decreased more with increased counterclockwise rotation of the mandible. CONCLUSION: Compared to the non-extraction group, there were more increases in the AOP-SN and AOP-POP angle and more posterior flattening in patients with four premolar extractions despite different types of dentoskeletal malocclusion, which were correlated to the change of variables in sagittal and vertical dimensions such as Wits and FHI.

Machine-learning-based detection of degenerative temporomandibular joint diseases using lateral cephalograms.

INTRODUCTION: Degenerative temporomandibular joint diseases (DJDs) are common diseases in dental practice, characterized by a series of degenerative processes in the temporomandibular joint. Early clinical detection of DJD by dental practitioners can be beneficial to prevent or alleviate the further progression of the disease. This study aimed to develop a cephalogram-based multidimensional nomogram to screen DJD. METHODS: A total of 502 patients (170 normal and 332 with DJD) were randomly assigned to a training set (n = 351) or a validation set (n = 151). Thirty-six cephalometric parameters were extracted from the cephalograms to be used as input for a predictive machine-learning algorithm. Multivariable logistic regression was used to construct a combined model for visualization in the form of a nomogram. Receiver operating characteristic curve, calibration testing, and decision curve analyses were conducted to evaluate the performance of the combined model. RESULTS: A Ceph score consisting of 22 cephalometric parameters were significantly associated with DJD (P <0.01). A combined model that consisted of Ceph scores and clinical features (including age, gender, limited mouth opening, crepitus, etc.) performed well in the receiver operating characteristic curve (area under the curve, 0.893), calibration test, and decision curve analyses, indicating its potential clinical value. CONCLUSIONS: This study constructed and verified a multidimensional nomogram consisting of Ceph scores and clinical features, which may contribute to the clinical screening of DJD in dental practice. Future studies are needed to test the reliability of the model with similar parameters.

Comparison and applicability of three induction methods of temporomandibular joint osteoarthritis in murine models.

BACKGROUND: Temporomandibular joint osteoarthritis (TMJ-OA) causes severe symptoms such as chewing difficulties, acute pain and even maxillofacial deformity. However, there is hardly any effective disease-curing strategy because of uncertainty in aetiology. Animal model is an excellent tool to investigate the mechanism, prevention and treatment on diseases. Currently, although several TMJ-OA animal models have been established, there are almost no comparative studies on different models, which poses a great challenge for selecting suitable models. OBJECTIVE: To compare three TMJ-OA induction methods and assess their applicability considering pathological changes in the cartilage, subchondral bone, osteoclasts, and synovium. METHODS: Murine models were employed and followed for 3 and 6 weeks after experimental procedures (surgery, injection, crossbite). The TMJ changes were evaluated by Safranin-O/Fast green staining, immunofluorescence staining, micro-CT, TRAP staining, and HE staining. RESULTS: In the Surgery group, a pronounced drop in bone volume fraction was observed. In the Injection group, chondrocytes were mostly disordered or arranged in clusters and a substantial increase in the OARSI score and osteoclasts was found. The OARSI score and osteoclasts also increased significantly in the Crossbite group, although to a lower extent compared with injection. CONCLUSION: Osteoarthritis-like changes were observed in all models. Concerning the applicability of the different induction methods, surgery might be an important resource for the assessment of post-traumatic TMJ-OA and subchondral bone changes in early stages. Injection induces a severe end-stage osteoarthritis in a short time and provides model basis for advanced TMJ-OA. Crossbite might be more reasonable model to explore the pathogenesis mechanism of temporomandibular arthritis due to occlusal disorders.

d-mannose attenuates lipopolysaccharide-induced osteolysis via CPT1A-Mediated lipid metabolic regulation in macrophages.

Inflammatory osteolysis is usually linked to the activation of proinflammatory macrophage and the consequent excessive osteoclast formation. Emerging evidence indicates that agents or drugs targeting lipid metabolism in macrophages might be potential in the prevention and treatment of osteolysis. d-mannose, as a natural-existed metabolic regulator, exerts strong effects on attenuating osteopenia and inflammation. However, whether d-mannose is therapeutically effective on osteolysis and whether a metabolic mechanism counts for the effect remain to be addressed. Here, by using an in vivo lipopolysaccharide (LPS)-induced inflammatory osteolysis mouse model as well as an in vitro LPS-induced inflammatory macrophage culture system, we show that d-mannose attenuates inflammatory osteolysis and inhibits excessive osteoclastogenesis by reversing the LPS-induced activation of proinflammatory macrophage. Mechanically, d-mannose recovers LPS-suppressed Cpt1a transcription and promotes lipid metabolism of macrophage. Treatment with etomoxir, an inhibitor of CPT1A, abolishes the effects of d-mannose on LPS-treated macrophage in vitro and eliminates its protection against osteolysis in vivo. Collectively, our results imply that d-mannose attenuates LPS-induced osteolysis by manipulating CPT1A-mediated lipid metabolism in macrophages. Our results disclose the unrecognized utilization of d-mannose as an effective intervention against inflammatory osteolysis and provide evidence to manage inflammatory scenarios by therapeutically targeting lipid metabolism in macrophage.

Psychological status of TMD patients, orthodontic patients and the general population during the COVID-19 pandemic.

Confronting the outbreak of COVID-19, this cross-sectional study was aimed to assess psychological status of temporomandibular disorders (TMD) patients, orthodontic patients and the general population in China during the pandemic. An online anonymous questionnaire was developed in Chinese, including the individual background information, the perception of the epidemic, and level of anxiety and depression through Kessler Psychological Distress Scale (K10). The respondents were divided into ORTHO group, TMD group and Control group. Descriptive analysis and multiple linear regression modelling were performed. In total, 1241 valid questionnaires were collected, covering 587 orthodontic patients and 220 TMD patients. It is shown that the overall mental health is not quite optimistic during the COVID-19 pandemic with the mean score of K10 being 18.65. TMD patients have higher level of anxiety and depression than orthodontic patients as well as the general population. Younger age, female gender, having close contact with individuals from Hubei province, higher self-rated infection possibility, concern about psychological barriers and distrust are negatively affecting patients' psychological status. Mental health care should be emphasized when hospitals and clinics reopen after the COVID-19 pandemic, especially to patients with these relevant characteristics.

Mental distress in orthodontic patients during the coronavirus disease 2019 pandemic.

INTRODUCTION: The ongoing coronavirus disease 2019 (COVID-19) outbreak impacts the mental health of patients, health workers, and the public. The level of impact on the mental health of orthodontic patients in treatment is unknown. The objective of the study was to evaluate the mental health of orthodontic patients in China during the early stage of the pandemic. METHODS: An online survey was conducted on a convenience sample of anonymous participants. The questionnaire, in Chinese (Mandarin), comprised 5 sections. Sections 1-3 included demographic, epidemical, and orthodontic status of the patients. Section 4 assessed mental health-related to orthodontics. Section 5 was the Kessler-10 Mental Distress Scale. A total of 48 orthodontists were invited to distribute the questionnaires to their patients. Descriptive statistics, principal component analysis, K-means cluster analysis, and bivariate logistics regression analysis were performed with significance set at P <0.05. RESULTS: Questionnaires were collected from 558 patients (104 males, 354 females; mean age 24.78 ± 6.33 years). The prevalence of mental distress was 38% (174/458). Higher odds ratios were associated with female participants, missed appointments, and Hubei residence. The type of orthodontic appliance was associated with the anxiety of prolonged treatment duration. The manner of communication with patients regarding the postponement of appointments was associated with patients' concerns of prolonged treatment duration. The frequency of contact from dentists was associated with patients' independence. CONCLUSIONS: Over one-third of orthodontic patients experienced mental distress during the pandemic. Multiple factors affected the level of anxiety of orthodontic patients, such as the type of orthodontic appliance, time since last dental visit, manner of communication with the orthodontist, and the localities of the pandemic progression.

Distribution of Various Maxilla-Mandibular Positions and Cephalometric Comparison in Chinese Skeletal Class II Malocclusions.

AIM: To obtain the distribution of different maxilla-mandibular characteristics in Chinese skeletal class II mixed dentition patients and to compare the differences of cephalometric variables among different maxilla-mandibular types. MATERIALS AND METHODS: A cross-sectional study was conducted among 310 skeletal class II patients in mixed dentition. The patients were divided into 6 groups according to SNA and SNB angle of the cephalogram. A total of 38 cephalometric measurements were measured on their cephalograms. Differences among groups were tested by one-way analysis of variance. RESULTS: There were 34 (10.97%) patients in group I, 10 (3.23%) in group II, 4(1.29%) in group III, 69 (22.26%) in group IV, 133 (42.90%) in group V, and 60 (19.35%) in group VI. In all, 14.19% of the patients exhibited maxillary protrusion (MxP), and 62.26% exhibited mandibular retrusion (MnR) with either normal or retruded maxilla. Groups II and III were excluded for statistical comparison due to a limited sample size. Statistical differences were found in 25 cephalometric measurements among the other 4 groups. Patients with MnR (groups V and VI) exhibited bigger sella angle, gonial angle, Frankfort mandibular plane angle, and smaller mandibular body length and ramus height than patients without MnR (p value < 0.05). CONCLUSION: The most common etiology forming skeletal class II malocclusion in Chinese children was MnR, which was mainly caused by the small size and hyperdivergent growth direction of mandible. CLINICAL SIGNIFICANCE: The study presents various cephalometric characteristics of Chinese skeletal class II malocclusions. The results indicated that for the early orthodontic treatment of Chinese class II children with mixed dentition, orthodontists might emphasize more importance to mandibular length augmentation and growth direction change in mandible.

A prospective and randomized study comparing ultrasound-guided real time injection to conventional blind injection of botulinum neurotoxin for glabellar wrinkles.

BACKGROUND: Botulinum neurotoxin injections are the most frequently performed cosmetic procedures, but conventional blind injection for glabellar wrinkles remains to have some limitations. AIMS: We intend to directly inject botulinum neurotoxin into the glabella complex guided by real time ultrasound. We aim to propose a more efficient and safer botulinum neurotoxin injection strategy for glabellar wrinkles. METHODS: A total of 40 subjects with moderate to severe glabellar lines were enrolled in this study to receive botulinum neurotoxin injection, either through ultrasound-guided real time injection or conventional blind injection. Facial Wrinkle Scale (ranging from 0 = none to 3 = severe) and inter-brow distance (from 3D scanned face images) were used to evaluate the glabellar wrinkles improvement. Paired t test and two-sample t test were performed to analyze the within-group and between-group differences. RESULTS: The wrinkle score reduction was significant (p < 0.0001) immediately after the injection in ultrasound-guided injection group, but not in blind injection group (p = 0.163). Ultrasound-guided injection also showed a higher performance of wrinkle score reduction and more effective inter-brow distance increase over blind injection at Day 0 (p < 0.0001), Day 1 (p < 0.0001), Day 21 (p < 0.01) and Day 35 (p < 0.01) after initial treatment. CONCLUSIONS: The results of the study confirmed that botulinum neurotoxin injection for glabellar wrinkles under ultrasound guidance achieves quicker onset of action and better final outcomes compared to conventional blind injection.

Abnormal dental follicle cells: A crucial determinant in tooth eruption disorders (Review).

The dental follicle (DF) plays an indispensable role in tooth eruption by regulating bone remodeling through their influence on osteoblast and osteoclast activity. The process of tooth eruption involves a series of intricate regulatory mechanisms and signaling pathways. Disruption of the parathyroid hormone­related protein (PTHrP) in the PTHrP­PTHrP receptor signaling pathway inhibits osteoclast differentiation by DF cells (DFCs), thus resulting in obstructed tooth eruption. Furthermore, parathyroid hormone receptor­1 mutations are linked to primary tooth eruption failure. Additionally, the Wnt/ß­catenin, TGF­ß, bone morphogenetic protein and Hedgehog signaling pathways have crucial roles in DFC involvement in tooth eruption. DFC signal loss or alteration inhibits osteoclast differentiation, affects osteoblast and cementoblast differentiation, and suppresses DFC proliferation, thus resulting in failed tooth eruptions. Abnormal tooth eruption is also associated with a range of systemic syndromes and genetic diseases, predominantly resulting from pathogenic gene mutations. Among these conditions, the following disorders arise due to genetic mutations that disrupt DFCs and impede proper tooth eruption: Cleidocranial dysplasia associated with Runt­related gene 2 gene mutations; osteosclerosis caused by CLCN7 gene mutations; mucopolysaccharidosis type VI resulting from arylsulfatase B gene mutations; enamel renal syndrome due to FAM20A gene mutations; and dentin dysplasia caused by mutations in the VPS4B gene. In addition, regional odontodysplasia and multiple calcific hyperplastic DFs are involved in tooth eruption failure; however, they are not related to gene mutations. The specific mechanism for this effect requires further investigation. To the best of our knowledge, previous reviews have not comprehensively summarized the syndromes associated with DF abnormalities manifesting as abnormal tooth eruption. Therefore, the present review aims to consolidate the current knowledge on DFC signaling pathways implicated in abnormal tooth eruption, and their association with disorders of tooth eruption in genetic diseases and syndromes, thereby providing a valuable reference for future related research.

ANKRD22 knockdown suppresses papillary thyroid cell carcinoma growth and migration and modulates the Wnt/ß-catenin signaling pathway.

The incidence of thyroid cancer is escalating globally, particularly among women. Studies have demonstrated the abnormal activation of Ankyrin Repeat Domain 22 (ANKRD22) in various cancers, but it remains uncertain whether it is also highly expressed in papillary thyroid carcinoma (PTC). Our objective was to evaluate the role of ANKRD22 in PTC. The expression of ANKRD22 varies among tissues, as validated by the Cancer Genome Atlas, and further predicted using the Tumor Immune Estimation Resource. Predicted results were examined via polymerase chain reaction and western blotting. Subsequently, the expression of ANKRD22 in cells was suppressed by RNA interference, and changes in cell progression were examined in conjunction with the cell counting kit-8 assay, transwell assay, and colony formation assay. Finally, the effects of ANKRD22 knockdown on the Epithelial-to-Mesenchymal transition and the Wnt/ß-catenin signaling pathway were investigated through western blotting. An in vivo mice model was established to validate the effect of ANKRD22. This study discovered that ANKRD22 was highly expressed in PTC, which was validated by polymerase chain reaction and western blotting. Knockdown of ANKRD22, significantly reduced thecell viability, colony formation capability, and cell invasion and migration abilities. Furthermore, we found that knockdown of ANKRD22 impaired both tumor Epithelial-to-Mesenchymal transition and the activation of the Wnt/ß-catenin signaling pathway. In conclusion, this study revealed that the knockdown of ANKRD22 inhibits the growth and migration of papillary thyroid cell carcinoma by regulating the Wnt/ß-catenin signaling pathway.

Evaluation of the Properties of 3D-Printed Ti Alloy Plates: In Vivo and In Vitro Comparative Experimental Study.

Titanium (Ti)-based implants play a significant role in rigid internal fixation in maxillofacial surgery. No study has reported that three-dimensional-printed Ti alloy plates (3D-Ti plates) have comprehensively excellent properties similar to standard plates (Matrix-MANDIBLE, SYNTHES, Switzerland) (Synthes-Ti plates). In this work, we manufactured 3D-Ti plates by selective laser melting with Ti6Al4V powder. The surface morphology, mechanical properties, and bone-plate contact rate of the 3D-Ti plates and the Synthes-Ti plates were characterized and compared via electron microscopy, atomic force microscopy, Vickers hardness test, three-point bending test, and software calculation. Human bone marrow stromal cells (HBMSCs) were cultured on the plates to test their biocompatibility. Importantly, the 3D-Ti plates were placed into a mandibular fracture model to assess the effect of medical application for 4 and 24 weeks. The 3D-Ti plates were demonstrated to have similar biocompatibility and stability for rigid internal fixation with the Synthes-Ti plates, lower roughness (106.44 ± 78.35 nm), better mechanical strength (370.78 ± 1.25 HV10), and a higher bone-plate contact rate (96.9%). These promising results indicate the feasibility of using 3D-Ti plates for irregular shapes and complex anatomical structures in a clinical context.

Agaricus blazei Murrill Polysaccharide Attenuates Periodontitis via H2 S/NRF2 Axis-Boosted Appropriate Level of Autophagy in PDLCs.

SCOPE: Periodontitis is one of the most prevalent chronic inflammatory diseases with impaired autophagy. Agaricus blazei Murrill polysaccharide (ABMP) shows beneficial effects in various inflammatory diseases. However, whether ABMP is involved in autophagy regulation and periodontitis attenuation remains to be elucidated. METHODS AND RESULTS: This study firstly shows the dynamic changes in inflammatory and autophagy levels in silk ligature periodontitis model. Then the positive regulation effect of autophagy on inflammation and its vital role in ABMP inhibiting PDLCs inflammatory response are testified in LPS-treated PDLCs. Secondly, the Micro-CT, quantitative RT-PCR, Western Blot, TRAP, and immunofluorescence staining analysis are performed to assess the effects of ABMP on periodontitis and autophagy. The data show the augmented autophagy and alleviated gingival recession, inflammatory cell infiltration, alveolar bone resorption, and reduced osteoclasts in periodontitis by ABMP treatment. Further experiments using chemical inhibitors demonstrate the vital role of H2 S/NRF2 axis in ABMP-induced appropriate level of autophagy augmentation against periodontitis. CONCLUSIONS: Collectively, the findings not only reveal the unrecognized capacity and mechanism of ABMP as an effective and potential dietary intake against periodontitis, but also suggest the possibility for ABMP to be used in the treatment of other autophagy-related diseases.

Association between the severity of hypodontia and the characteristics of craniofacial morphology in a Chinese population: A cross-sectional study.

Objective: To investigate craniofacial differences in individuals with hypodontia and explore the relationship between craniofacial features and the number of congenitally missing teeth. Methods: A cross-sectional study was conducted among 261 Chinese patients (males, 124; females, 137; age, 7-24 years), divided into four groups (without hypodontia: no teeth missing, mild: one or two missing teeth, moderate: three to five missing teeth, severe: six or more missing teeth) according to the number of congenitally missing teeth. Differences in cephalometric measurements among the groups were analyzed. Further, multivariate linear regression and smooth curve fitting were performed to evaluate the relationship between the number of congenitally missing teeth and the cephalometric measurements. Results: In patients with hypodontia, SNA, NA-AP, FH-NA, ANB, Wits, ANS-Me/N-Me, GoGn-SN, UL-EP, and LL-EP significantly decreased, while Pog-NB, AB-NP, N-ANS, and S-Go/N-Me significantly increased. In multivariate linear regression analysis, SNB, Pog-NB, and S-Go/N-Me were positively related to the number of congenitally missing teeth. In contrast, NA-AP, FH-NA, ANB, Wits, N-Me, ANS-Me, ANS-Me/N-Me, GoGn-SN, SGn-FH (Y-axis), UL-EP, and LL-EP were negatively related, with absolute values of regression coefficients ranging from 0.147 to 0.357. Further, NA-AP, Pog-NB, S-Go/N-Me, and GoGn-SN showed the same tendency in both sexes, whereas UL-EP and LL-EP were different. Conclusions: Compared with controls, patients with hypodontia tend toward a Class III skeletal relationship, reduced lower anterior face height, flatter mandibular plane, and more retrusive lips. The number of congenitally missing teeth had a greater effect on certain characteristics of craniofacial morphology in males than in females.

Nano-Drug Delivery Systems in Oral Cancer Therapy: Recent Developments and Prospective.

Oral cancer (OC), characterized by malignant tumors in the mouth, is one of the most prevalent malignancies worldwide. Chemotherapy is a commonly used treatment for OC; however, it often leads to severe side effects on human bodies. In recent years, nanotechnology has emerged as a promising solution for managing OC using nanomaterials and nanoparticles (NPs). Nano-drug delivery systems (nano-DDSs) that employ various NPs as nanocarriers have been extensively developed to enhance current OC therapies by achieving controlled drug release and targeted drug delivery. Through searching and analyzing relevant research literature, it was found that certain nano-DDSs can improve the therapeutic effect of drugs by enhancing drug accumulation in tumor tissues. Furthermore, they can achieve targeted delivery and controlled release of drugs through adjustments in particle size, surface functionalization, and drug encapsulation technology of nano-DDSs. The application of nano-DDSs provides a new tool and strategy for OC therapy, offering personalized treatment options for OC patients by enhancing drug delivery, reducing toxic side effects, and improving therapeutic outcomes. However, the use of nano-DDSs in OC therapy still faces challenges such as toxicity, precise targeting, biodegradability, and satisfying drug-release kinetics. Overall, this review evaluates the potential and limitations of different nano-DDSs in OC therapy, focusing on their components, mechanisms of action, and laboratory therapeutic effects, aiming to provide insights into understanding, designing, and developing more effective and safer nano-DDSs. Future studies should focus on addressing these issues to further advance the application and development of nano-DDSs in OC therapy.

College Students with Oral Habits Exhibit Worse Psychological Status and Temporomandibular-Related Quality of Life: A Correlational Study.

Purpose: To evaluate the relationship between oral habits, psychological status, and temporomandibular-related quality of life among college students. Materials and Methods: An online questionnaire was sent to college students who were willing to participate in this anonymous survey, which contained questions about the demographic characteristics of the participants, the Patient Health Questionnaire for Depression and Anxiety (PHQ-4), the Fonseca Anamnestic Index (FAI), and the Oral Health Impact Profile for temporomandibular disorders (OHIP-TMDs). Results: A total of 505 valid questionnaires were collected from 200 males and 305 females (a mean age of 21.81 ± 2.81 years). The prevalence of oral habits in college students was 58% (294/505). Female gender (odds ratio (OR) 1.786) and having oral habits (OR 1.893) were associated with depression and anxiety. Medical students had significantly less depression and anxiety (OR 0.459) than nonmedical students. The possibility of suffering from temporomandibular disorder (TMDs) as evidenced by the OHIP-TMDs score was associated with female gender (OR 1.989) and having oral habits (OR 3.482). Students with oral habits had higher OHIP-TMDs scores. Conclusion: More than half of the college students surveyed had specific oral habits, with a higher prevalence in women than in men. Having oral habits was related to a worse psychological status, higher risk of TMD, and worse temporomandibular-related quality of life.

A new frontier in temporomandibular joint osteoarthritis treatment: Exosome-based therapeutic strategy.

Temporomandibular joint osteoarthritis (TMJOA) is a debilitating degenerative disease with high incidence, deteriorating quality of patient life. Currently, due to ambiguous etiology, the traditional clinical strategies of TMJOA emphasize on symptomatic treatments such as pain relief and inflammation alleviation, which are unable to halt or reverse the destruction of cartilage or subchondral bone. A number of studies have suggested the potential application prospect of mesenchymal stem cells (MSCs)-based therapy in TMJOA and other cartilage injury. Worthy of note, exosomes are increasingly being considered the principal efficacious agent of MSC secretions for TMJOA management. The extensive study of exosomes (derived from MSCs, synoviocytes, chondrocytes or adipose tissue et al.) on arthritis recently, has indicated exosomes and their specific miRNA components to be potential therapeutic agents for TMJOA. In this review, we aim to systematically summarize therapeutic properties and underlying mechanisms of MSCs and exosomes from different sources in TMJOA, also analyze and discuss the approaches to optimization, challenges, and prospects of exosome-based therapeutic strategy.

Nonlinear Relationship between Temporomandibular Joint Disc Displacement Distance and Disc Length: A Magnetic Resonance Imaging Analysis.

Objective: to explore the association between the distance of disc displacement and disc morphology in patients with temporomandibular disorders (TMDs). Methods: a total of 717 joints in 473 subjects were enrolled in this cross-sectional study. The magnetic resonance imaging (MRI) of each patient was evaluated for temporomandibular joint (TMJ) disc morphology classification and position. The distance of the disc displacement and disc length were measured for smoothing spline prediction. A stratified analysis was performed based on the types of disc positions. The disc width and length-width ratio (L/W) were also measured. Descriptive statistics, one-way analysis of variance, smoothing spline analysis, threshold analysis, and two piecewise linear regression were performed to investigate the association between the displacement distance and length of discs. Results: the differences in displacement distance among morphological categories and among different disc positions were statistically significant. Nonlinear relationships were found between distance and length in all subjects. Two turning points of distance (−1.8 mm and 1.7 mm) were found, dividing the curve into three segments. Disc width and L/W were significantly different among discs in the three segments of the curve. The correlation coefficient (ß) for the three segments were as follows: −0.6 [95% confidence interval (CI) = −0.9 to −0.3, p < 0.001], 0.0 (95% CI = −0.1 to 0.0, p = 0.027), and −0.7 (95% CI = −0.8 to −0.7, p < 0.001). Nonlinear relationships were also found between the distance and length in cases with anterior disc displacement (ADD), anterior disc displacement with reduction (ADDWR), and without reduction (ADDWoR). Conclusion: the turning points of the disc displacement distance may be considered as a potential reference value for high-risk disc deformation and ADD. Disc length decreases sharply with anterior disc displacement when the disc displacement distance is over 1.7 mm. Prospective and long-term studies are required to clarify the natural course of the disc at different stages of the regression curve.

Gli1+ Mesenchymal Stem Cells in Bone and Teeth.

Mesenchymal stem cells (MSCs) are remarkable and noteworthy. Identification of markers for MSCs enables the study of their niche in vivo. It has been identified that glioma-associated oncogene 1 positive (Gli1+) cells are mesenchymal stem cells supporting homeostasis and injury repair, especially in the skeletal system and teeth. This review outlines the role of Gli1+ cells as MSC subpopulation in both bones and teeth, suggesting the prospects of Gli1 an + cells in stem cell- based tissue engineering.

SM22α-lineage niche cells regulate intramembranous bone regeneration via PDGFRß-triggered hydrogen sulfide production.

Bone stromal cells are critical for bone homeostasis and regeneration. Growing evidence suggests that non-stem bone niche cells support bone homeostasis and regeneration via paracrine mechanisms, which remain to be elucidated. Here, we show that physiologically quiescent SM22α-lineage stromal cells expand after bone injury to regulate diverse processes of intramembranous bone regeneration. The majority of SM22α-lineage cells neither act as stem cells in vivo nor show their expression patterns. Dysfunction of SM22α-lineage niche cells induced by loss of platelet-derived growth factor receptor ß (PDGFRß) impairs bone repair. We further show that PDGFRß-triggered hydrogen sulfide (H2S) generation in SM22α-lineage niche cells facilitates osteogenesis and angiogenesis and suppresses overactive osteoclastogenesis. Collectively, these data demonstrate that non-stem SM22α-lineage niche cells support the niche for bone regeneration with a PDGFRß/H2S-dependent regulatory mechanism. Our findings provide further insight into non-stem bone stromal niche cell populations and niche-regulation strategy for bone repair.

Tetraspanin 1 (TSPAN1) promotes growth and transferation of breast cancer cells via mediating PI3K/Akt pathway.

The incidence and mortality of breast cancer rank first among all types of female tumors. To improve patients' prognosis with advanced breast cancer, new and more effective targets still need to be explored and identified. Tetraspanin 1 (TSPAN1) is highly expressed in several cancers and affects the progression of these tumors. However, there are few studies focused on its role in breast cancer. Previous study showed that TSPAN1 promoted epithelial-mesenchymal transition (EMT) and metastasis, and whether TSPAN1 could promote breast cancer via regulating EMT needs further study. In this study, we found high TSPAN1 expression in breast cancer tumor samples and cell lines which was confirmed by bioinformation analysis. The ablation of TSPAN1 suppressed the growth, and motility of breast cancer cells. We further found that TSPAN1 affected the EMT and mediated the PI3K/Akt pathway in breast cancer cells. In addition, TSPAN1 depletion suppressed tumor growth of breast cancer in mice. In summary, we thought TSPAN1 suppressed growth and motility of breast cancer via mediating EMT and PI3K/AKT pathway, and could serve as a potential target for treatment of breast cancer.