In addition to apoptosis, necroptosis also plays critical roles in pathological changes in mandibular cartilage after compressive mechanical force stimulation, implying RIP1, a master protein that mediates both necroptosis and apoptosis, as a potential therapeutic target in temporal mandibular osteoarthritis.

In this study, silk thread (Bombyx mori) was braided to a tube-like shape and sericin was removed from the silk tube. Thereafter, collagen/chondroitin-6-sulfate solution was poured into the silk tube, and the lyophilization process was performed. To assess the inflammatory response in vivo, raw silk and sericin-free silk tubes were implanted in the subcutaneous layer of mice. After 10 days of in vivo implantation, mild inflammatory responses were observed around the sericin-free silk tubes, and severe inflammation with the presence of neutrophils and macrophages was observed around the raw silk tubes. At 24 weeks post implantation, the regenerated tendon had a thick, cylindrical, grayish fibrous structure and a shiny white appearance, similar to that of the native tendon in the rabbit model of tendon defect. The average tensile strength of the native tendons was 220 ± 20 N, whereas the average tensile strength of the regenerated tendons was 167 ± 30 N and the diameter of the regenerated tendon (3 ± 0.2 mm) was similar to that of the native tendons (4 ± 0.3 mm). Histologically, the regenerated tendon resembled the native tendon, and all the regenerated tissues showed organized bundles of crimped fibers. Masson trichrome staining was performed for detecting collagen synthesis, and it showed that the artificial tendon was replaced by new collagen fibers and extracellular matrix. However, the regenerated tendon showed fibrosis to a certain degree. In conclusion, the artificial tendon, comprising a braided silk tube and lyophilized collagen sponge, was optimal for tendon reconstruction. Thus, this study showed an improved regeneration of neo-tendon tissues, which have the structure and tensile strength of the native tendon, with the use of the combination of collagen and silk scaffold.

The novel coronavirus disease 2019 , characterized by symptoms of fever and pneumonia, was reported in Wuhan, China, at the end of 2019 (Phelan, Katz, & Gostin, 2020). Given the likely transmission of COVID-19 via droplets and aerosols during dental clinical procedures, dental practitioners are at a high risk of COVID-19 infections (Ather, Patel, Ruparel, Diogenes, & Hargreaves, 2020). According to the guidelines of the Chinese Stomatological Association (CSA), dental clinics in China suspended the routine dental services and only provided emergency dental care between January and April 2020 (CSA, 2020). The objective of the study was to investigate the influence of COVID-19 on patients' utilization of dental services during the COVID-19 pandemic.This study was carried out from April 20 to April 27 after the hospital reopening to the public and was approved by the Ethics Committee of Nanjing Stomatological Hospital. A total of 1,032 patients with a dental appointment record in the Nanjing Stomatological Hospital were recruited in the study. A 24-item questionnaire was used to survey patients' demographics, psychological state, behaviour and awareness of COVID-19, and their evaluations on the current dental services (Appendix S1). Sample size was calculated based on the data obtained from the hospital registration system, using a power of 95% and a 3.07% margin of error. Statistical analysis was performed using SPSS 16 (IBM, USA). Kruskal-Wallis H tests were performed to explore the associated factors of different degrees of stress during dental health care visit. p-Value <.05 was considered significant.A total of 956 valid questionnaires were collected, yielding a response rate of 92.6%. Most respondents were females (65.1%), adults < 40 years old (72.3%), living in this city (82.9%) and revisit patients (75.5%) (Table 1). The main reason for patients' visit

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Excessive mechanical loads on the temporomandibular joint (TMJ) can cause mandibular cartilage degradation and subchondral bone erosion, but the treatment of these conditions remains challenging. Salubrinal, which target eukaryotic translation initiation factor 2 alpha, has been shown to have multiple beneficial effects on skeletal tissue. Here, we examined the effect of a Salubrinal injection on the mandibular cartilage and subchondral bone of the TMJ under various compressive stresses. We conducted in vivo analyses in rat models using various compressive stresses (40 g and 80 g), and we observed time-related degeneration and pathological changes in the cartilage and subchondral bone of the TMJ at days 1, 3 and 7 through histological measurements, subcellular observation, and changes in proliferation and apoptosis. After the Salubrinal injection, the thickness of the cartilage recovered, and the pathological change was alleviated. In the Salubrinal/light (Sal/light) compressive stress group, the drug altered the proliferation and apoptosis of chondrocytes most significantly at day 1. In the Salubrinal/heavy (Sal/heavy) compressive stress group, the drug increased the proliferation of chondrocytes most significantly at day 1 and reduced the apoptosis of chondrocytes most significantly at day 7. Salubrinal also increased the area of the bone trabeculae and suppressed inflammatory responses and pathological change in the subchondral bone of the TMJ. Together, these results indicate that the administration of Salubrinal reduces apoptosis and strengthens the proliferation of chondrocyte to varying degrees at days 1, 3 and 7 under various compressive mechanical stresses, both of which contribute to the recovery of cartilage thickness and the alleviation of pathological change. Salubrinal also suppresses inflammatory responses and pathological change in the subchondral bone of the TMJ.