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.

Tissue injury provokes a series of events containing inflammation, new tissue formation and tissue remodeling which are regulated by the spatially and temporally coordinated organization. It is an evolutionarily conserved, multicellular, multi-molecular process via complex signalling network. Tissue injury disorders present grievous clinical problems and are likely to increase since they are generally associated with the prevailing diseases such as diabetes, hypertension and obesity. Although these dynamic responses vary not only for the different types of trauma but also for the different organs, a balancing act between the tissue degradation and tissue synthesis is the same. In this process, the degradation of old extracellular matrix (ECM) elements and new ones' synthesis and deposition play an essential role, especially collagens. Lysyl oxidase (LOX) and four lysyl oxidase-like proteins are a group of enzymes capable of catalyzing cross-linking reaction of collagen and elastin, thus initiating the formation of covalent cross-links that insolubilize ECM proteins. In this way, LOX facilitates ECM stabilization through ECM formation, development, maturation and remodeling. This ability determines its potential role in tissue repair and regeneration. In this review, based on the current in vitro, animal and human in vivo studies which have shown the significant role of the LOXs in tissue repair, e.g., tendon regeneration, ligament healing, cutaneous wound healing, and cartilage remodeling, we focused on the role of the LOXs in inflammation phase, proliferation phase, and tissue remodeling phase of the repair process. By summarizing its healing role, we hope to shed light on the understanding of its potential in tissue repair and provide up to date therapeutic strategies towards related injuries.

Hyposalivation is an intractable side-effect of radiotherapy for head and neck cancer. It is caused by the irreversible loss of acinar cells and decreased saliva secretion. However, this situation severely compromises the quality of life of affected patients. Currently, there is no effective treatment for this condition. In the present study, we developed a novel approach to regenerate the function of the irradiation-damaged salivary glands using human adipose tissue-derived stem cell (hADSC) intraglandular transplantation. ZsGreen-labeled hADSCs were adoptively transferred into Sprague-Dawley (SD) rat submandibular glands immediately following exposure to 18 Gy irradiation. A higher salivary flow rate (SFR) was observed in the hADSC-treated group. Tissue improvement, including angiogenesis, anti-apoptosis and anti-fibrosis, was detected in the hADSC-treated glands as compared to the untreated glands. Quantitative reverse transcription PCR (RT-qPCR) revealed a significantly higher expression of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), cyclooxygenase-2 (COX-2) and matrix metalloproteinase-2 (MMP-2) in the hADSC-treated rats. Furthermore, immunohistochemical analysis indicated that the hADSCs had differentiated into acinar and ductal cells in the rat submandibular glands. Thus, our results suggest that hADSCs are able to regenerate irradiation-damaged salivary glands through glandular transplantation.

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.

Temporomandibular joint disorders (TMDs) are a prevalent disease covering pain and dysfunction of temporomandibular joints and masticatory muscles, which can be detrimental to quality of life. Magnetic resonance imaging (MRI) is a powerful and noninvasive tool for the imaging and understanding of TMD. With the recent technical development of dynamic and quantitative MRI techniques, including diffusion‐weighted imaging, T2 mapping, and ultrashort/zero echo time, it is now feasible in TMD imaging and has been preliminarily investigated with promising results. In this review we will discuss the recent advances of MRI techniques in TMD and its future directions, and hope to highlight the scientific potential and clinical value of novel MRI techniques in diagnosing and treating TMD. Level of Evidence 4 Technical Efficacy Stage 3