Biosafety in Dental Health Care During the COVID-19 Pandemic: A Longitudinal Study.

Background: The coronavirus disease 2019 (COVID-19) pandemic had quite an impact on dental health care. Concerns about the risk of SARS-CoV-2 transmission through contaminant fluids and droplet formation during several dental procedures highly impacted dental health care, drastically reducing the number of dental practices worldwide. To monitor SARS-CoV-2 contamination in dental clinics, a longitudinal study was carried out during the return of dental practice at university. Methods: Dental health care professionals [(DHCPs); teachers, undergraduate dental students, and dental assistants] and patients were screened for SARS-CoV-2 RNA in a dental school clinic environment from 11th January to 12th March 2021 (9 weeks). Serological testing was performed on DHCPs in two-time points. Additionally, samples with low Ct values were sequenced to identify the circulating SARS-CoV-2 variant and possible transmission clusters. Results: We found a low number of dental staff (5.8%), patients (0.9%), and environment sites (0.8%) positive for SARS-CoV-2. Most positive cases had asymptomatic to mild symptoms, and two asymptomatic DHCPs presented prolonged infection. In the first week after previous exposure to COVID-19, 16.2% of DHCPs had IgM or IgG antibodies against SARS-CoV-2, and 1/3 of them had undetected antibodies in the last weeks. The variant zeta (P.2) could be detected. No cross-infection was observed between participants. Conclusion: Our study suggests that dental practice can be safely executed when adequate control measures and biosafety protocols are applied. DHCP and patient testing, patient telemonitoring, proper use of personal protection equipment, and sanitization of surfaces are essential to avoid SARS-CoV-2 cross-infection in dental practice.

Leiomyoma and Leiomyosarcoma (Primary and Metastatic) of the Oral and Maxillofacial Region: A Clinicopathological and Immunohistochemical Study of 27 Cases.

Smooth muscle neoplasms represent an important group of lesions which is rare in the oral cavity. Leiomyoma (LM) is benign smooth muscle/pericytic tumor usually presenting as non-aggressive neoplasm, while leiomyosarcoma (LMS) represents its malignant counterpart. The rarity of these lesions, together with its unspecific clinical presentation and a variable histopathological appearance, lead to a broad list of differential diagnoses, hampering their diagnoses. Therefore, in this study we describe the clinical and microscopic features of a series of oral and maxillofacial LMs and LMSs. A retrospective search from 2000 to 2019 was performed and all cases diagnosed as LM and LMS affecting the oral cavity and gnathic bones were retrieved. Clinical and demographic data were obtained from the patients' pathology records, while microscopic features and immunohistochemistry were reviewed and completed when necessary to confirm the diagnoses. Twenty-two LMs and five LMSs were obtained. In the LM group, males predominated, with a mean age of 45.7 years. The upper lip was the most affected site, and 18 cases were classified as angioleiomyomas and four as solid LM. In the LMS group, females predominated, with a mean age of 47.6 years. The mandible was the most affected site. Diffuse proliferation of spindle cells, with necrosis and mitotic figures, were frequent microscopic findings. LMs and LMSs were positive for α-smooth muscle actin, HHF-35 and h-caldesmon. In conclusion, oral LM/LMS are uncommon neoplasms with the latter usually presenting as metastatic disease. H&E evaluation may be very suggestive of oral LMs, but h-caldesmon staining is strongly recommended to confirm LMS diagnosis.

DNA Methylation patterns of immune response-related genes in inflammatory external root resorption.

Inflammatory external root resorption (IERR) is a pathological process defined by the progressive loss of dental hard tissue, dentin, and cementum, resulting from the combination of the loss of external root protective apparatus and root canal infection. It has been suggested that healing patterns after tooth replantation may be influenced by the genetic and immunological profiles of the patients. The purpose of the present investigation was to evaluate the DNA methylation patterns of 22 immune response-related genes in extracted human teeth presenting with IERR. Methylation assays were performed on samples of root fragments showing IERR and compared with healthy bone tissue collected during the surgical extraction of impacted teeth. The methylation patterns were quantified using EpiTect Methyl II Signature Human Cytokine Production PCR Array. The results revealed significantly higher hypermethylation of the FOXP3 gene promoter in IERR (65.95%) than in the bone group (23.43%) (p < 0.001). The ELANE gene was also highly methylated in the pooled IERR sample, although the difference was not statistically significant (p= 0.054). Our study suggests that the differential methylation patterns of immune response-related genes, such as FOXP3 and ELANE, may be involved in IERR modulation, and this could be related to the presence of root canal infection. However, further studies are needed to corroborate these findings to determine the functional relevance of these alterations and their role in the pathogenesis of IERR.

Effects of aging on DNA hydroxymethylation and methylation in human dental follicles.

OBJECTIVE: Despite the high frequency of impacted teeth and increased frequency of lesions in dental follicles (DF) with aging, DF age-changes remain unclear. We compared the global methylation and hydroxymethylation profiles in DF in relation to age. DESIGN: DF associated with impacted lower third molars were obtained from 59 individuals. Global DNA methylation (5mC content) and hydroxymethylation (5hmC) were evaluated by ELISA. We tested the correlation between 5mC and 5hmC content, and the correlation of each with patients' age. The differences in age, 5mC, and 5hmC in DF from men/women, and location (left/right mandible) was tested. RESULTS: The mean age of the 59 individuals was 19.56 ±â€¯3.92, ranging from 13 to 31 years, and most were women (n = 39). 5hmC content and age up to 19 years were inversely correlated (Spearman's correlation coefficient=-0.552, p = 0.0003, n = 38). There was no relationship between 5hmC and 5mC content. There was no difference in the medians of age (p = 0.25), 5hmC (p = 0.33) and 5mC (p = 0.86) between men/women, nor in the medians of age (p = 0.39), 5hmC (p = 0.99) and 5mC (p = 0.22) between the left/right side of the tooth extraction. CONCLUSION: An inverse correlation between 5hmC and age was established, with no correlation between 5mC and 5hmC content in DF. The biological meaning of such a decrease of global DNA hydroxymethylation with age in DF remains to be clarified.

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.

Loss of heterozygosity and immunoexpression of PTEN in oral epithelial dysplasia and squamous cell carcinoma.

INTRODUCTION: Oral epithelial dysplasia (OED) is a risk factor for developing subsequent oral squamous cell carcinoma (OSCC). Loss of heterozygosity (LOH) profiles have been validated as risk predictors of malignant transformation of OED. It is still unclear if Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) allelic loss also occurs in initial stage malignant lesions and if the allelic loss is involved as one of the mechanisms of oral carcinogenesis. Thus, this study objective investigate LOH of PTEN gene and the immunohistochemical expression of the protein in OED and OSCC samples. MATERIAL AND METHODS: Formalin-fixed paraffin-embedded samples of 19 OEDs and 16 OSCCs were included to immunohistochemistry and LOH analysis. Two polymorphic microsatellite markers (AFMA086WG9 and D10S1765) located in chromosome 10 were used in this study for LOH analysis. For immunohistochemical analysis, 5 random fields with 400× magnification were evaluated quantitatively and qualitatively in epithelial and neoplastic cells. RESULTS: AFMA086WG9 marker only demonstrated LOH in OEDs cases (10.5%). D10S1765 marker demonstrated LOH in 57.2% of OEDs and 50% of OSCCs. Higher nuclear immunostaining was detected in cases of OSCCs when compared to OEDs (p < .001) and there was strong cytoplasmic immunoexpression in OSCCs (p < .045). CONCLUSIONS: We provide evidence that the allelic loss of PTEN is present in premalignant oral lesions and OSCCs, however the LOH of PTEN does not seems to influence its protein expression.

DNA Methylation patterns of immune response-related genes in inflammatory external root resorption

Abstract Inflammatory external root resorption (IERR) is a pathological process defined by the progressive loss of dental hard tissue, dentin, and cementum, resulting from the combination of the loss of external root protective apparatus and root canal infection. It has been suggested that healing patterns after tooth replantation may be influenced by the genetic and immunological profiles of the patients. The purpose of the present investigation was to evaluate the DNA methylation patterns of 22 immune response-related genes in extracted human teeth presenting with IERR. Methylation assays were performed on samples of root fragments showing IERR and compared with healthy bone tissue collected during the surgical extraction of impacted teeth. The methylation patterns were quantified using EpiTect Methyl II Signature Human Cytokine Production PCR Array. The results revealed significantly higher hypermethylation of the FOXP3 gene promoter in IERR (65.95%) than in the bone group (23.43%) (p < 0.001). The ELANE gene was also highly methylated in the pooled IERR sample, although the difference was not statistically significant (p= 0.054). Our study suggests that the differential methylation patterns of immune response-related genes, such as FOXP3 and ELANE, may be involved in IERR modulation, and this could be related to the presence of root canal infection. However, further studies are needed to corroborate these findings to determine the functional relevance of these alterations and their role in the pathogenesis of IERR.

Análise proteômica quantitativa em ameloblastomas / Quantitative proteomic analysis in ameloblastomas

O ameloblastoma é um tumor odontogênico epitelial benigno caracterizado por crescimento lento localmente agressivo, alta morbidade e grande potencial de recidiva. Apesar dos avanços em bioinformática que levaram ao desenvolvimento de tecnologias que permitiram o estudo das ciências "ômicas", há escassos estudos de proteômica em ameloblastomas. O nosso objetivo, portanto, foi realizar uma análise quantitativa do perfil proteômico de ameloblastomas em comparação a folículos pericoronários. No presente estudo, nós utilizamos a estratégia de proteômica shotgun para identificação de proteínas usando a combinação de cromatografia líquida e espectrometria de massas em tandem (liquid chromatography-tandem mass spectrometry; LC-MS/MS). Também foram realizadas análises de cluster e de enriquecimento funcional das proteínas que apresentaram abundâncias alteradas nos ameloblastomas. Nesse estudo realizou-se ainda avaliação do status de mutação em BRAF nos casos de ameloblastoma. Por fim, a validação dos resultados da etapa de proteômica foi feita por meio de imunoistoquímica. A análise proteômica quantitativa comparativa resultou na identificação de 1.353 proteínas. Os ameloblastomas mostraram um perfil proteômico distinto daquele encontrado nos folículos dentais, com 33 proteínas super-reguladas e 21 para sub-reguladas. As proteínas super-reguladas estão envolvidas no metabolismo da glicose e nas vias de biossíntese de macromoléculas, indicando um mecanismo adaptativo de crescimento do tumor, enquanto a maioria das proteínas sub-reguladas desempenha papéis importantes na produção de energia celular mitocondrial e na regulação do metabolismo de oxidorredutase, sugerindo disfunção mitocondrial e resposta ao estresse oxidativo. BRAF p.V600E foi detectado na maioria dos ameloblastomas e pode estar relacionado à indução de fluxo glicolítico, assim como ao estresse oxidativo. Para investigar a ativação do sistema antioxidante, nós avaliamos a imunoexpressão da enzima antioxidante denominada glutationa S-transferase ômega 1 (GSTO1), que foi super-regulada nos ameloblastomas. Os ameloblastomas mostraram imunoexpressão de GSTO1 difusa e com intensidade moderada a forte, enquanto uma imunoexpressão fraca ou negativa de GSTO1 foi observada nos folículos pericoronários. Nossa hipótese é que o ameloblastoma apresenta reprogramação metabólica glicolítica com alta geração de precursores biossintéticos. Além disso, foi observada uma baixa abundância de componentes respiratórios mitocondriais, o que está possivelmente associado à disfunção mitocondrial. Nós identificamos pela primeira vez alterações em vias metabólicas críticas que não só contribuem para a elucidação da patogênese do ameloblastoma, mas também podem ser alvos terapêuticos potenciais para esses tumores

Ameloblastoma is a benign epithelial odontogenic tumor characterized by slow but locally aggressive growth, high morbidity and great potential for recurrence. Despite the advances in bioinformatics that led to the development of technologies that allowed the study of omics sciences, there are scarce studies of proteomics in ameloblastomas. Our aim was to perform a quantitative analysis of the proteomic profile of ameloblastomas compared to dental follicles. In the present study, we performed shotgun proteomics to identify proteins using the combination of liquid chromatography and tandem mass spectrometry (LC-MS/MS). We also performed cluster and functional enrichment analyses of proteins with altered abundances in ameloblastomas. This study also carried out an assessment of the BRAF mutation status in cases of ameloblastoma. Finally, the validation of the results of the proteomics step was performed using immunohistochemistry. Quantitative comparative proteomic analysis resulted in the identification of 1,343 proteins. Ameloblastomas were shown to harbor a proteomic profile distinct from that found in dental follicles, with 33 over-regulated and 21 down-regulated proteins. Overregulated proteins are involved in glucose metabolism and biosynthesis pathways, indicating an adaptative tumor growth mechanism. Most of the down-regulated proteins play prominent roles in cellular mitochondrial energy production and oxidoreductase metabolism regulation, suggesting mitochondrial dysfunction and oxidative stress response. BRAF p.V600E was detected in most ameloblastomas and it may be related to the induction of glycolytic flux, as well as oxidative stress. To investigate the activation of the antioxidant system, we assessed the immunoexpression of the antioxidant enzyme glutathione S-transferase omega 1 (GSTO1), which was up-regulated in ameloblastomas. Ameloblastomas showed diffuse and moderate to strong GSTO1 immunoexpression, whereas weak or negative imunoexpression was observed in dental follicles. We hypothesize that ameloblastoma presents metabolic reprogramming towards a more glycolytic state with high biosynthetic precursor generation. In addition, a low abundance of mitochondrial respiratory components possibly associated with mitochondrial dysfunction was observed. We were able to identify for the first-time alterations in critical metabolic pathways, which not only contribute to the elucidation of ameloblastoma pathogenesis but also could be potential targets for drug therapy in these tumors.

Epstein-Barr Virus-Positive Diffuse Large B-Cell Lymphoma, Not Otherwise Specified, in the Oral Cavity.

Lymphomas of the oral cavity are rare and the most frequent type is diffuse large B-cell lymphoma (DLBCL). Epstein-Barr virus (EBV) is known to be associated with the development of different lymphomas. In 2008, the World Health Organization provisionally included the EBV-positive DLBCL of the elderly in the classification of hematopoietic and lymphoid tumors as a lymphoma occurring in older individuals without any known immunodeficiency. However, it has since been recognized that this entity may occur in younger individuals and present similar clinical parameters in both age groups. As a result, the 2017 revision has declined the term elderly and modified it to EBV-positive DLBCL, not otherwise specified (NOS). In this report, we describe a rare case of EBV-positive DLBCL, NOS, presenting as a painless swelling in the oral cavity. This entity shows a more aggressive clinical course than EBV-negative DLBCL, and other lymphoproliferative disorders should be considered in the differential diagnosis.

t(6;9)(MYB-NFIB) in head and neck adenoid cystic carcinoma: A systematic review with meta-analysis.

The presence of a translocation involving MYB and NFIB genes have been described in adenoid cystic carcinoma (AdCC) from different anatomical regions. However, the exact frequency of this genetic event and its prognostic impact for patient survival remain obscure. The aim of this study was to carry out a systematic review to address the prevalence and the prognostic potential of t(6;9)(MYB-NFIB) in head and neck AdCC. Quantitative analysis was done to determine the prevalence of the translocation. A total of 1,107 articles were initially retrieved with 36 remaining for data extraction. The prevalence of t(6;9)(MYB-NFIB) varied significantly (16%-100%), especially due to methodological heterogeneity among studies. A total of 11 studies attempted to determine the prognostic importance of the translocation, but no study found any significant association with survival rates; only three studies observed a significant association with age, sex, tumour location and the presence of recurrences and metastases. The prevalence of t(6;9)(MYB-NFIB) in head and neck AdCC varies according to the laboratorial methods used, and the best evidence available demonstrates that t(6;9)(MYB-NFIB) does not seem to be a prognostic determinant.

DNA methylation polymerase chain reaction (PCR) array of apoptosis-related genes in pleomorphic adenomas of the salivary glands.

OBJECTIVE: The aim of this study was to evaluate the DNA methylation profile in 22 apoptosis-related genes in pleomorphic adenomas (PAs) of the salivary glands, in comparison with normal salivary glands (NSGs), and to address the differences in methylation patterns between smaller and larger tumors. Additionally, we investigated if the hypermethylation of differentially methylated genes between NSGs and PAs impacted the messenger RNA (mRNA) transcription. DESIGN: Twenty-three fresh PA samples and 12 NSG samples were included. The PA samples were divided into 2 groups: PAs with clinical size larger than 2 cm (n = 12) and PAs with clinical size 2 cm or smaller (n = 11). DNA methylation at the promoter region of a panel of 22 genes involved in apoptosis was profiled by using a human apoptosis DNA methylation polymerase chain reaction array, and the transcriptional levels of genes showing differential methylation profiles between PAs and NSGs were assessed. RESULTS: TNFRSF25 and BCL2 L11 were highly methylated in PAs, in comparison with NSGs, irrespective of tumor size. However, no difference could be observed in the mRNA transcription between PAs and NSGs. CONCLUSIONS: Hypermethylation of the proapoptotic genes BCL2 L11 and TNFRSF25 is observed in PA. However, this phenomenon did not impact mRNA transcription.

DNA methylation profiles of 22 apoptosis-related genes in odontogenic keratocysts before and after marsupialization.

OBJECTIVE: Odontogenic keratocysts (OKCs) are cystic lesions of the jaw and tend to recur after treatment. Marsupialization is an effective preliminary treatment for large OKCs. This procedure induces epithelial lining changes in association with reduction of Bcl-2 protein expression, but the underlying mechanisms remain unknown. The purpose of our study was to compare the methylation profile of the apoptosis-related genes of OKCs before and after marsupialization. STUDY DESIGN: We assessed the methylation percentages of the promoter region of 22 apoptosis-related genes in 13 OKCs, both marsupialized and nonmarsupialized lesions, by using methylation quantitative polymerase chain reaction array. We validated the expression of genes that showed the greatest differences in methylation percentages between the 2 groups. RESULTS: LTBR and BCLAF1 showed higher DNA methylation percentages in the marsupialized OKCs, but this difference did not affect gene expression (P > .05). The other 20 genes showed similar DNA methylation in both OKC groups. CONCLUSIONS: OKCs show a distinct methylation profile after marsupialization, but this is not followed by gene expression alterations.