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Many viral infections cause oral manifestations, including disorders in odontogenesis, resulting in dental malformations. In this review, based on current knowledge, we will discuss the likely dental and oral consequences of COVID-19. In this article, we review currently available data associated with vertical transmission of COVID-19 and odontogenesis, oral manifestations, and the impact of COVID-19 pandemic on a diagnosis of oral diseases. Owing to the severity of the pandemic, the population's anxiety and fear of becoming infected with COVID-19 may underestimate the signs and symptoms of serious illnesses, besides discourage patients from seeking health, medical or dental services to determine the diagnosis of oral lesions. Thus, the COVID-19 pandemic could be an additional and aggravating factor for the delay of serious illness diagnosis, such as oral squamous cell carcinoma resulting in higher morbidity and worse prognosis. Several changes and oral lesions have been described as oral manifestations of COVID-19, such as dysgeusia, oral ulcers, petechiae, reddish macules, desquamative gingivitis, among others. Besides, it can cause major systemic changes and predispose opportunistic infections. As with other viral infections, oral manifestations, including dental anomalies, can occur as a direct result of SARS-CoV-2 infection. However, further studies are needed to guide and clarify possible oral changes.

Nowadays we have clinical need to develop innovative biomaterials which provide dual functionality: regeneration of bone tissue and inhibition of pathogenic microorganisms. Glass-ceramic materials are interesting options. The aim of this study was to produce, characterize and evaluate the bio-reactivity and the antimicrobial effect of these materials doped with strontium ions using in vitro methodology. Crystalline powders (CP) of composition similar to S53P4 glass and Sr-modified were produced via sol-gel route and treated at 800 ° C. For the CP containing this ion, molar substitution of 12.5% or 25% of CaO by SrO was carried out. Three analytical groups were obtained: CP without Sr (CPSr0), CP with 12.5% Sr (CPSr12.5) and CP with 25% Sr (CPSr25). The CPs were characterized by Xray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Zeta sizer and thermogravimetric analysis (TGA / DTG). The antimicrobial effect was verified through the macrodilution and death curve tests (1, 6, 12, 24, 48 and 72 hours) (concentration ≤ 100 mg/mL) against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Streptococcus mutans and yeasts of the genus Candida: C. albicans, C. glabrata, C. krusei e C. tropicalis. Bio-reactivity was evaluated in vitro by immersion in simulated body fluid (SBF) (24, 72 and 168 hours) by means of scanning electron microscopy (SEM) and FTIR analyzis. The obtained gels partially crystallized to form a sodium-calcium silicate phase (combeite). The increasing substitution of CaO by SrO showed characteristic absorption band for SrO binding. The CPs had mean particle sizes of 1.61 ± 0.24 μm (CPSr0), 1.88 ± 0.48 μm (CPSr123.5) and 1.48 ± 0.41 μm (CPSr25). SEM images showed irregular and porous surface particles. The evaluated powders inhibited the growth of the microorganisms, demonstrating complete inhibition in the first 6h, except for S. mutans when exposed to CPSr12.5 (complete inhibition in 24h) and CPSr25 (complete inhibition in 48h) and E. faecalis when exposed to CPSr0 (complete inhibition in 24h), CPSr12.5 and CPSr25 (complete inhibition in 72h). pH values higher than 10 were obtained for the culture medium in the first 6 h, which shows a positive correlation with the inhibitory effect for the microorganisms evaluated. CPSr12.5 and CPSr25 showed higher bioactivity, with total surface coating by HA in 7 days of immersion in SBF. In addition, characteristic bands of HA in FTIR were observed for all groups. The pH increased rapidly in the first 24 h after immersion of the powders in SBF, reaching a maximum value of 8.72 ± 0.03 (CPSr0), 8.70 ± 0.02 (CPSr12.5) and 8.70 ± 0.03 (CPSr25) after 168 h. Replacement of CaO by SrO did not change the overall structure of the material. HA formation was observed, with emphasis on strontium powders. All powders showed an inhibitory effect on oral pathogens. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Atualmente existe necessidade clínica de desenvolver biomateriais inovadores que forneçam dupla funcionalidade: regeneração do tecido ósseo e inibição de micro-organismos patogênicos. Materiais vitrocerâmicos são opções interessantes. Com esse fim objetivou-se produzir, caracterizar e avaliar in vitro a bio-reatividade e o efeito antimicrobiano de materiais dopados com íons estrôncio. Pós cristalinos (CP) de composição similar ao vidro S53P4 e modificados com Sr foram produzidos via rota sol-gel e tratados termicamente a 800 °C. Para os CP contendo este íon, foi realizada a substituição em mol de 12,5 % ou 25 % de CaO por SrO. Três grupos de amostras foram obtidos: CP sem Sr (CPSr0), CP com 12,5 % de Sr (CPSr12,5) e CP com 25 % de Sr (CPSr25). Os CP foram caracterizados por difração de raios X (DRX), espectroscopia de infravermelho por transformada de Fourier (FTIR), microscopia eletrônica de varredura (MEV), Zeta sizer e análises termogravimétrica e termodiferencial (TGA/DTG). O efeito antimicrobiano foi verificado através dos testes de macrodiluição e curva de morte (1, 6, 12, 24, 48 e 72 h) (concentração ≤ 100 mg/mL) sobre bactérias Staphylococcus aureus, Escherichia coli, Enterococcus faecalis e Streptococcus mutans e leveduras do gênero Candida: C. albicans, C. glabrata, C. kruseri e C. tropicalis. A bio-reatividade foi avaliada in vitro por imersão em fluido corporal simulado (SBF) (24, 72 e 168 horas), e analisada por MEV e FTIR. Os pós obtidos apresentaram-se parcialmente cristalinos com fase sódio-cálcio-silicato, combeita. A substituição crescente de CaO por SrO apresentou banda de absorção característica para a ligação SrO. Os CP apresentaram tamanhos médios de partículas de 1,61 ± 0.24 µm (CPSr0), 1,88 ± 0.48 µm (CPSr123,5) e 1,48 ± 0.41 µm (CPSr25). Micrografias mostraram partículas de superfície irregular e porosa. Os pós avaliados inibiram o crescimento dos micro-organismos, demonstrando inibição completa nas primeiras 6h, exceto para o S. mutans ao ser exposto aos materiais CPSr12,5 (inibição completa em 24h) e CPSr25 (inibição completa em 48h) e E. faecalis ao ser exposto ao CPSr0 (inibição completa em 24h), CPSr12,5 e CPSr25 (inibição completa em 72h). Valores de pH maiores que 10 foram obtidos para o meio de cultura nas primeiras 6 h, o que mostra uma correlação positiva com o efeito inibitório para os micro-organismos avaliados. CPSr12,5 e CPSr25 demonstraram maior bioatividade, com recobrimento total da superfície por hidroxiapatita (HA) em 7 dias de imersão em SBF. Além disso, observou-se bandas características de HA no FTIR para todos os grupos. O pH aumentou rapidamente nas primeiras 24 h após a imersão dos pós em SBF, atingindo um valor máximo de 8,72 ± 0,03 (CPSr0), 8,70 ± 0,02 (CPSr12,5) e 8,70 ± 0,03 (CPSr25) após 168 h. A substituição de CaO por SrO não alterou a estrutura geral do material. Observou-se formação de HA, com destaque para os pós com estrôncio. Todos os pós demonstraram efeito inibitório sobre os patógenos bucais.