Background: on 7 January 2020, a new type of coronavirus was isolated, the Severe Acute Respiratory Syndrome Coronavirus2 (SARS-CoV-2), the organism causing the outbreak that has affected the lives of all humans and has modified the rules of coexistence around the world. In Mexico, from 3 January 2020 to 9 January 2021, there have been 1439, 569 confirmed cases of COVID-19 with 131,031 deaths. The World Health Organization reported that Mexico was ranked twelfth, in terms of confirmed cases of COVID-19 by country. Aim: the objective of this study was to determine what modifications dentists from the Mexican Republic have made to their dental practice during theCOVID-19 pandemic. Methods: the study was conducted based on a questionnaire to evaluate the dentists’ response and knowledge on the modifications in their dental practice to combat the new coronavirus’s cross-transmission. The questionnaire was piloted before it was distributed. The questionnaire was disseminated through the social network Facebook. The questionnaire was distributed to groups of dentists on Facebook, in each of the Mexican Republic states. The survey was carried out during June 2020. Results and Conclusions: from the 32 states of the Mexican Republic, 29 participated with at least one respondent. The results of the applied survey suggest that dentists, at least the population of surveyed ones, have proper knowledge of detection methods of patients suspected of COVID-19, preventive measures that must be applied in the dental office to decrease the risk of infection, and the appropriate procedures and solutions for dental office disinfection.

Background and Objectives: The aim of this systematic review is to summarize the current data about the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its entry factors in oral tissues and cells. Materials and Methods: This systematic review was carried out based on the Preferred Reporting Items for a Systematic Review and Meta-Analysis (PRISMA). Three databases were analyzed (Pubmed, Web of science and Scopus) by three independent researchers. From the 18 identified studies, 10 of them met the inclusion criteria. The presence of SARS-CoV-2 or its entry factors (angiotensin-converting enzyme II (ACE2), transmembrane serine proteases (TMPRSS), and furin) was analyzed in these 10 studies during the pandemic. Results: ACE2 expression was analyzed in 9 of the 10 studies. ACE2 is expressed mainly in the tongue, oral mucosa, salivary glands and epithelial cells. The expression of the TMPRSS2 gene or protein was analyzed in 6 studies. These studies reported that the expression of TMPRSS2 was mainly in the salivary glands, tongue, sulcular epithelium and oral mucosa; as well as in cells of the salivary glands (ductal, acinar and myoepithelial cells) and the tongue (the spinous-based cell layer, horny layer and the epithelial surface). Other TMPRSS were also reported. The expression of TMPRSS3, TMPRSS4, TMPRSS5, TMPRSS7 and TMPRSS11D was reported mainly in salivary glands and in epithelial-type cells. Furan expression was analyzed in three studies. The expression of furin was detected mainly in epithelial cells of the tongue. A variety of methods were used to carry out the detection of SARS-CoV-2 or its input molecules. Conclusions: These results show that SARS-CoV-2 can infect a wide variety of oral tissues and cells, and that together with the theories dedicated to explaining the oral symptoms present in SARS-CoV-2 positive patients, it provides us with a good scientific basis for understanding the virus infection in the oral cavity and its consequences.

The objective of this study was to estimate the prevalence of permanent teeth loss in a university population of adolescents and young adults, and also to determine the distribution by age and sex. A cross-sectional study was carried out in a sample of 1027 adolescents and young adults from 16 to 25 years old selected randomly from the total number of applicants to the bachelor's degree program of San Luis Potosi University, Mexico. The dependent variable was the prevalence of tooth loss, codified as "0"=subjects without tooth loss and "1"=subjects with at least one tooth loss. Others variables included were age and sex. Analyzes was performed in STATA 9.0 with logistic regression. The mean of age was 18.20±1.65 and 52.0% were men. The prevalence of tooth loss was 18.0% (n=185) and the mean of 0.46±1.13, whereas in subjects with at least one tooth loss the mean was 2.54±1.32. The maximum number of teeth loss was 5. In the adjusted model we obtained statistic significance in the age (OR=1.11; p<0.05). Women have 41% high risk to present at least one tooth loss than men. Subjects that presented more of 6 filling have high possibility to have teeth loss (OR=1.60; p<0.05). Findings indicate that the experience to have tooth loss reaches nearly 20.0%, and that there was relationship between tooth loss and age, sex and number of fillings. This study demonstrates the existence of gender inequalities.

The microhardness is an essential property of tooth enamel; there may be many factors that alter or diminish this quality causing weakness, one of which is dental fluorosis. The aim of this study was evaluate the surface microhardness of fluorotic enamel compared with healthy enamel. Two hundred forty extracted human molars were classified into four groups: Healthy (H), mild (MI), moderate (MO) and severe (S) fluorosis according to the Dean index. All samples were analyzed by Micro Vickers Hardness Tester. Average, standard deviation and ranges were calculated for quantitative variables, the ANOVA and Tukey test was used to identify differences between groups. The mean values of surface microhardness in HVN were: H, 333.4; MI, 290.3; MO, 266.1; S, 252.0. The differences between mean surface microhardness among healthy group and fluorotic groups were statistically significant (p

Background The global spread of COVID-19 forced schools at all educational levels to close, which was repeated in more than 60 countries. In addition, the COVID-19 pandemic has affected the mental health of dental students world wide. This study hypothesizes that the prevalence of depression in dental students from El Salvador is higher than that reported in studies from Europe, Asia, and North America. Methods This study was an online cross-sectional survey performed at the Faculty of Dentistry of the University of Salvador. The PHQ-9 questionnaire was applied to know the level of depression of the students, and a questionnaire focused on learning the opinion of the students on the hybrid teaching model adopted. Approximately 450 students participated in both questionnaires. Results Regarding the levels of depression present in the students, 14% had minimal depression, 29% had medium depression, 23% had moderate depression and, 34% had severe depression. The students had an excellent opinion regarding the hybrid learning model. Conclusions The prevalence of depression in dental students in El Salvador seems to be higher than that reported in studies in non-Latin American countries. Therefore, universities must generate care plans for mental health to avoid these harmful effects on students during future contingencies.