Purpose/objectives To investigate dental students’ perceptions and concerns regarding the COVID‐19 pandemic, their coping strategies and support resources, and their perceived stress levels. Methods A customized 19‐item survey and the perceived stress scale (PSS) were applied to undergraduate dental students from the US, Spain, Ireland, Chile, India, and Brazil between April 10 and July 5, 2020. Linear modeling and mediation analysis were used to explore the relationships among demographics, stressors, coping mechanisms, social support, and stress Results A total of 4475 students responded to the survey. The majority (72.4%) were women, and 52.3% had no COVID‐19 training at the time of the survey. The students reported that they had to accommodate to changes in patient care (96.6%) and didactic learning (95.2%) activities, while 88.5% of the respondents indicated at least one of their courses moved online. Transition to online courses went “smoothly with some troubles” for 51.8% of the respondents, and 48.3% perceived the faculty as prepared for the online transition; however, 45.9% reported feeling extremely concerned about the impact of COVID‐19 on their education. The average PSS score was 21.9 of 40 (moderate stress). Multivariate models were built for participants with full data (n = 3899). Being male, having completed more dental coursework, and perceiving a smoother transition were associated with lower PSS scores; more concern about academic progress was associated with higher PSS. Faculty support mediated the relationship between a smoothness of transition and concern about academic progress and PSS scores Conclusion Stress caused by the pandemic may be alleviated by smoother transition and good faculty support.

Since oral squamous cell carcinoma (OSCC) is the most prevalent malignant cancer in the oral cavity, several researches have been performed to study the role of important enzymes in this disease. Among them, the matrix metalloproteinases (MMPs) are highlighted, due to the fact that they are proteinases responsible to degrade many extra-cellular matrix components, making possible the invasion of neoplasic cells. Important tools in cancer prognosis have been utilized aiming to correlate high levels of MMPs and OSCC, such as immunohistochemical, zymographic and mRNA detection methods. However, these techniques are usually applied after cancer detection, characterizing a curative but not a preventive medicine. Trying to make interventions before the development of the disease and making possible the identification of people at high risk and, analysis of modifications in MMP genes has been a chance for modern medicine. Recently, polymorphisms in MMP genes have been related to different neoplasias, including OSCC. Despite investigation is beginning, MMP gene polymorphisms seems to have a promising future in oral cancer research and some of the present results have shown that there are MMP polymorphisms related to an increased risk for developing oral cancer. Key words:Oral cancer, polymorphism, matrix metalloproteinase.

No carcinoma epidermóide, os processos de invasão e metástase são regulados por um complexo sistema dependente da interação entre as células neoplásicas e as células estromais hospedeiras. Esses processos ocorrem como conseqüência à degradação da membrana basal e da matriz extracelular por diversas enzimas, dentre as quais as metaloproteinases da matriz (MMP) apresentam destaque. Essas são enzimas zinco-dependentes, pouco expressas em tecidos normais e substancialmente aumentadas na maioria das neoplasias malignas. Dentre todas as MMP conhecidas, as MMP-2 e -9 (gelatinases) têm sido consistentemente associadas com a agressividade, o potencial metastático e o prognóstico desfavorável das neoplasias malignas. As gelatinases desempenham um papel fundamental no processo da carcinogênese, pois degradam principalmente colágeno tipo IV, componente fundamental da membrana basal, participando do processo de invasão do estroma e invasão dos vasos sangüíneos, processo fundamental para a metástase. Portanto, o objetivo desse trabalho foi apresentar uma revisão dos aspectos gerais das MMP, abordando principalmente as MMP-2 e -9, bem como suas relações com o desenvolvimento do carcinoma epidermóide, buscando as possibilidades de prevenção e tratamento.

No abstract