Abstract This study aimed to evaluate the effect of Bifidobacterium animalis subsp. lactis (B. lactis) HN019 in drinking water on the development of apical periodontitis (AP) in rats. In total 60 animals were divided into a control group (sound teeth); Group I - regular water without AP; Group II - probiotic water without AP; Group III - regular water with AP; Group IV - probiotic water with AP. AP was induced after 3 days in the control groups and after 7, 21, and 42 days in groups III and IV. The animals were euthanized, and the mandibles were subjected to histotechnical processing. Samples were stained with hematoxylin & eosin (H&E) to identify root canal features, apical and periapical regions. Additionally, histoenzymology was performed to detect osteoclasts, immunohistochemistry was used to identify osteoclastogenesis markers, and the Brown & Brenn technique was applied for microbiological analysis. The data were analyzed using GraphPad Prism 8.0.1 with a significance level of 5%. Although no statistical differences were observed, the groups administered with probiotics showed better conditions in terms of histological aspects seen microscopically. Furthermore, there were no differences in the number of osteoclasts (p > 0.05). The RANKL marker was not found in the probiotic group at 42 days, unlike in group III.

Aim To evaluate the psychological impact of COVID-19 on undergraduate and graduate students of the Dental School of Ribeirão Preto, University of São Paulo. Methods Three questionnaires were used: sociodemographic, WHO Abbreviated Quality of Life Inventory, and General Anxiety Disorder-7. Data were analyzed using Graph Pad Prism 7a (α = 5%). Mann-Whitney or Kruskal-Wallis and Dunn post-tests were used for statistical comparisons. The Spearman test was used as the correlation test. Results 257 students responded to the online form that assessed their quality of life and anxiety level. On a scale from 1 to 100, with 100 being the best quality of life, the average obtained was 64.71 (± 13.36). In addition, 87.6% of the students rated their quality of life as good or very good. 74.7% reported good or very good health. The anxiety analysis resulted in an average of 10.04 (± 4.5), indicating moderate anxiety levels. There was an inversely proportional correlation between age and degree of anxiety (p = 0.008, r = -0.1628) and self-perceived learning and student commitment (r = 0.69). Conclusion Despite the good quality of life and the students’ good self-perception of health, they showed a moderate degree of anxiety during the social distancing caused by COVID-19, also demonstrating a decrease in interest and commitment during distance education.