Dental Care and the COVID-19 Pandemic: The Precautionary Principle and the Best Available Evidence

Abstract The precautionary principle is part of evidence-based healthcare and is used both preventively and therapeutically when there is no available evidence about how to manage problems/diseases/conditions that are especially life-threatening. However, since it is not always based in the most qualified evidence, it is frequently questioned. The emergence of a highly contagious disease, with increased levels of morbimortality, an acute respiratory syndrome, the so called Coronavirus Disease 2019 (COVID-19), led health professionals to look for the best alternatives to save lives. In this sense, the precautionary principle was evocated. The aim of this paper is to make a reflection about the precautionary principle, the dental profession and COVID-19. It is important to have in mind that in such a disease, guidelines, protocols and approaches can change very fast, since a continuous evaluation of all policies is mandatory. During the pandemic, elective procedures may be restricted, but international organizations removed the recommendation to postpone elective procedures. Clinicians are advised to be updated about their local current policies. On the other hand, there are cases in which in-office dental care is unavoidable, such as individuals with pain, spontaneous bleeding and dental trauma. Biosafety is upmost importance when seeking patients during pandemic. In this sense, it was concluded that precautionary principle should be, therefore, used. However, caution needs to be taken and continuous surveillance necessary.

Tratamento criogênico para elevar a quantidade de macroporos no plasma rico em fibrina utilizado como scaffold em engenharia tecidual / Cryogenic treatment to increase the amount of macropores in plasma rich in fibrin used as scaffold in tissue engineering

Objetivos: Investigar se o tratamento criogênico é capaz de elevar a quantidade de macroporos no Plasma Rico em Fibrina (PRF) utilizado como scaffold sem destruir totalmente sua integridade estrutural. Métodos: Três amostras de sangue (10 ml) foram processadas para obtenção do PRF. As amostras foram armazenadas em ultrafreezer (-80°C) e armazenadas por sete dias e um ano. Como controle foi utilizado um PRF imediatamente após sua obtenção. Após os respectivos períodos de armazenamento, cada PRF foi preparado para análises histológicas. Três áreas representativas de cada amostra foram selecionadas e avaliadas no software Image J quanto ao tamanho dos poros: macro ≥ 50 µm e microporos < 50 µm. Resultados: Após sete dias e um ano de criopreservação foi observada uma área total de macroporos compreendendo 76% e 82% do PRF, respectivamente. No PRF processado imediatamente após sua obtenção observamos 64% de macroporos. Além disso, a criopreservação promoveu uma alteração do arranjo estrutural do PRF. Conclusão: O tratamento criogênico do PRF a -80°C (por 7 dias ou um ano) foi capaz de elevar a quantidade de macroporos mantendo uma considerada quantidade de microporos. Com o aumento do tempo de tratamento criogênico um maior número de macroporos foi observado.

Objectives: To investigate whether the cryogenic treatment is able to increase the amount of macropores in the Fibrin Rich Plasma (PRF) used as scaffold, without destroying its structural integrity. Methods: Three blood samples (10 ml) were processed to obtain the PRF. The samples were stored in ultra-freezer (-80° C) and maintained for seven days or one year. As a control, PRF immediately after their acquisition was used. After each storage period, PRF was prepared for histological analysis. Three representative areas of each sample were selected and evaluated in Image J software for pore size: macro ≥ 50 µm and micropores < 50 µm. Results: After seven days and after one year of cryopreservation was observed a total area of macropores comprising 76% and 82% of the PRF, respectively. In PRF processed immediately after collection was observed 64% of macropores. As observed, the cryopreservation changed the structural arrangement of the PRF. Conclusion: The cryogenic treatment of PRF at -80 ° C (for 7 days or one year) increased the amount of macropores maintaining a considerate amount of micropores. A greater number of macropores was observed as the cryogenic treatment time was increased.