Can SARS-CoV-2 screening in oral biopsies aid epidemiological surveillance?

BACKGROUND: Three years after the first confirmed COVID-19 case in Brazil, the outcomes of Federal government omissions in managing the crisis and anti-science stance heading into the pandemic have become even more evident. With over 36 million confirmed cases and nearly 700 000 deaths up to January 2023, the country is one of the hardest-hit places in the world. The lack of mass-testing programs was a critical broken pillar responsible for the quick and uncontrolled SARS-CoV-2 spread throughout the Brazilian population. Faced with this situation, we aimed to perform the routine SARS-CoV-2 screening through RT-qPCR of oral biopsies samples to aid in the asymptomatic epidemiological surveillance during the principal outbreak periods. METHODS: We analyzed 649 formalin-fixed paraffin-embedded oral tissue samples from five important oral and maxillofacial pathology laboratories from the north, northeast, and southeast geographic regions of Brazil. We also sequenced the whole viral genome of positive cases to investigate SARS-CoV-2 variants. RESULTS: The virus was detected in 9/649 analyzed samples, of which three harbored the Variant of Concern Alpha (B.1.1.7). CONCLUSION: Although our approach did not value aiding asymptomatic epidemiological surveillance, we could successfully identify a using FFPE tissue samples. Therefore, we suggest using FFPE tissue samples from patients who have confirmed diagnosis of SARS-CoV-2 infection for phylogenetic reconstruction and contraindicate the routine laboratory screening of these samples as a tool for asymptomatic epidemiological surveillance.

Tobacco Use, Attitudes, Knowledge, and Perception About Smoking Cessation Counseling Among Brazilian Dental Students: a Cross-Sectional Study.

The aim of this study was to evaluate the prevalence of tobacco use, exposure to secondhand smoke, and knowledge and perception about smoking cessation counseling among dental students in Brazil. A cross-sectional study was performed at the School of Dentistry, Universidade Federal de Pernambuco, Brazil. The Global Health Professions Student Survey (GHPSS) research instrument was used. In the second half of 2017, students from the 5th to the 10th semester were recruited to answer the anonymous and self-administered survey in classrooms. The data were tabulated and analyzed, and information about the variables was presented using descriptive statistics. The association between the variables was determined through the Chi-square test and binary logistic regression. Two hundred and twenty-four students answered the survey. More than 40% of the students had tried cigarettes at least once and 8.9% were current smokers. About 28% of the participants reported having been exposed to secondhand smoke in their home and 57.1% in other environments. Most students recognized that they are role models for society and believed they should receive training in smoking cessation counseling. However, only 12.5% of the students reported having received some formal training in this subject. In conclusion, although dental students are aware of the harmful effects of tobacco, there is still a lack of training in smoking prevention and control among these future professionals.

A multicenter study of oral sarcomas in Brazil.

OBJECTIVES: The aim of this study was to investigate the prevalence of oral sarcomas from geographic regions of Brazil. MATERIALS AND METHODS: A cross-sectional study was conducted on biopsies obtained from January 2007 to December 2016 at twelve Brazilian oral and maxillofacial pathology centres. Gender, age, evolution time, clinical aspects, tumour location, tumour size at diagnosis, radiographic aspects and histopathological diagnosis were evaluated. Data were analysed using descriptive statistical methods. RESULTS: From 176,537, a total of 200 (0.11%) oral sarcomas were reported, and the most prevalent were osteosarcomas (74 cases; 37%) and Kaposi's sarcomas (52 cases; 26%). Males were more affected than females at a mean age of 32.2 years old (range of 3-87 years). The most common symptoms were swelling¸ localised pain and bleeding at a mean evolution time of 5.14 months (range <1-156 months). The lesions were mostly observed in the mandible (90 cases; 45%), with a mean tumour size of 3.4 cm (range of 0.3-15 cm). Radiographically, the lesions presented a radiolucent aspect showing cortical bone destruction and ill-defined limits. CONCLUSIONS: Oral sarcomas are rare lesions with more than 50 described subtypes. Osteosarcomas and Kaposi's sarcomas were the main sarcomas of the oral cavity in Brazil.

KRAS mutations drive adenomatoid odontogenic tumor and are independent of clinicopathological features.

Adenomatoid odontogenic tumor is a benign encapsulated epithelial odontogenic tumor that shows an indolent clinical behavior. We have reported in a few adenomatoid odontogenic tumors mutations in KRAS, which is a proto-oncogene frequently mutated in cancer such as lung, pancreas, and colorectal adenocarcinomas. We aimed to assess KRAS mutations in the hotspot codons 12, 13, and 61 in a large cohort of adenomatoid odontogenic tumors and to test the association of these mutations with clinical (age, site, tumor size, follicular/extrafollicular subtypes) and histopathological parameters. Thirty eight central cases were studied. KRAS codon 12 mutations were assessed by TaqMan allele-specific qPCR (p.G12V/R) and/or Sanger sequencing, and codon 13 and 61 mutations were screened by Sanger. Histological tumor capsule thickness was evaluated by morphometric analysis. Additionally, the phosphorylated form of the MAPK downstream effector ERK1/2 was investigated. Statistical analysis was carried out to test the association of KRAS mutations with clinicopathological parameters. KRAS c.35 G >T mutation, leading to p.G12V, was detected in 15 cases. A novel mutation in adenomatoid odontogenic tumor, c.34 G >C, leading to p.G12R, was detected in 12 cases and the other 11 were wild-type. Codon 12 mutations were not associated with the clinicopathological parameters tested. RAS mutations are known to activate the MAPK pathway, and we show that adenomatoid odontogenic tumors express phosphorylated ERK1/2. In conclusion, a high proportion of adenomatoid odontogenic tumors (27/38, 71%) have KRAS codon 12 mutations, which occur independently of the clinicopathological features evaluated. Collectively, these findings indicate that KRAS mutations and MAPK pathway activation are the common features of this tumor and some cancer types. Although it is unclear why different codon 12 alleles occur in different disease contexts and the complex interactions between tumor genotype and phenotype need clarification, on the basis of our results the presence of KRAS p.G12V/R favors the adenomatoid odontogenic tumor diagnosis in challenging oral neoplasm cases.

Effects of chronic treatment with botulinum toxin type A in salivary glands of rats: Histological and immunohistochemical analyses.

BACKGROUND: The intraglandular application of botulinum neurotoxin type A (BoNT-A) is used in patients with neuromotor disorders to control the escape of saliva. The aim of this study was to analyze the impact of repeated treatment with BoNT-A on the submandibular-sublingual complex of rats. METHODS: A total of 35 Wistar rats were divided into three groups: control group (C), in which animals were not treated; group B, treated with 2.5 U intraglandular injections of BoNT-A (Prosigne® ) and group G, that received bovine gelatine (Prosigne stabilizer). Three applications were performed in intervals of 35 days. Twelve and 35 days after ending the treatment, submandibular-sublingual complex was collected for histological analysis. Immunohistochemical reactions for calponin and specific muscle actin were also performed, besides detection of apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. RESULTS: A decrease in mucosal and serous acini diameter was observed, with increased interstitial space after 12 days of treatment with BoNT-A, which was observed in a lesser degree on the 35th day. At 12 days, immunohistochemical analysis revealed a decrease in myoepithelial cells of serous acini in group B. TUNEL methods evidenced apoptosis in animals from group B. CONCLUSIONS: BoNT-A caused histological and cellular changes in submandibular-sublingual complex, followed by a tendency toward reversal after 35 days. The reversal characteristic of cellular changes in the submandibular-sublingual complex suggests that this BoNT-A formulation may be safely used for sialorrhea treatment.

Pesticides as risk factors for head and neck cancer: A review.

Humans may be exposed to pesticides such as fungicides, herbicides, and insecticides, during occupational and non-occupational activities. Pesticides could be related to cancer development mainly because of their effects on the endocrine and immune systems and their cumulative effect. The present review evaluated in current literature evidence of an association between exposure to pesticides and the occurrence of head and neck cancer (HNC). A literature search for cohort studies was conducted in the PubMed, Web of science, and Cochrane databases. Methodological quality of each study was rated with the Scottish Intercollegiate Guidelines Network (SIGN) checklist. One thousand one hundred and thirty-two studies were identified. Thirty-two were included. Most of the studies found addressed occupational exposure to pesticides and were conducted in Europe and North America. Eleven high-quality studies were found. Most of them found no association between exposure to pesticides and increased risk of HNC. Two studies found some evidence of a positive association between pesticide (malathion and atrazine) exposure and thyroid cancer. The literature review does not support a clear evidence for association between pesticides exposure and HNC. Only limited evidence points to a positive association between exposure to some pesticides and thyroid cancer. Further standardized studies based on appropriate designs are required to clarify the effect of pesticides on the genesis of HNC, considering dose, length of exposure, and type of pesticide.

Knowledge and attitudes of Brazilian dental students and dentists regarding bisphosphonate-related osteonecrosis of the jaw.

PURPOSE: The aim of this study was to evaluate the knowledge of Brazilian dentists (DEN) and dental students (DS) about bisphosphonates (BP) and bisphosphonate-related osteonecrosis of the jaw (BRONJ). METHODS: A convenience sample of 104 DEN and 100 DS was randomly selected and invited to answer a questionnaire. The questionnaire was structured on the basis of the main information about BP and the risk factors associated with the development of BRONJ. The data obtained were analyzed by the chi-square and Fisher's exact tests, considering significance of 5%. RESULTS: Seventy-five (72.1%) DEN and 75 (75%) DS did not know the BP cited in the questionnaire (p < 0.0001), and their commercial brand names were not recognized by 88 (84.6%) DEN and 86 (86%) DS (p < 0.0001). In the same way, 62 (59.6%) DEN (p = 0.04) and 58 (58%) DS (p < 0.0001) did not recognize BRONJ as an oral side effect of BP or point out oral conditions that were not associated with the use of BP. CONCLUSIONS: Practical initiatives, such as free lectures and workshops, must be taken to broaden the knowledge of DEN and DS about BP and thus contribute to the prevention of BRONJ.

Ionizing radiation effects on the secretory-stage ameloblasts and enamel organic extracellular matrix.

This study assessed the effects of high doses of ionizing radiation on eruption rate, odontogenic region morphology, secretory-stage ameloblasts, and enamel organic extracellular matrix (EOECM) of rat maxillary incisors. For the study, 30 male rats were divided into three experimental groups: control (non-irradiated), irradiated by 15 Gy, and irradiated by 25 Gy. Irradiated groups received a single dose of 15 or 25 Gy of X-rays in the head and neck region. The maxillary incisor eruption rate was measured. Sections of 5-µm thickness of the maxillary incisor odontogenic regions were evaluated using bright field light microscopy. Ultrathin sections of secretory ameloblasts and their EOECM were analyzed by transmission electron microscopy (TEM). Irradiated groups showed significantly diminished eruption rate values at the 4th and at the 6th day after irradiation. Reduced optical retardation values were observed in the irradiated groups. The odontogenic region of maxillary incisors from irradiated rats exhibited altered and poorly organized preameloblasts. TEM showed degeneration areas in the secretory-stage EOECM and several autophagosomes in the secretory ameloblasts from irradiated animals. In conclusion, high radiation doses delay eruption and induce disturbances in secretory ameloblasts and EOECM of rat maxillary incisors. These findings may be associated with structural defects of mature enamel.