A Review of Prolonged Post-COVID-19 Symptoms and Their Implications on Dental Management

The available data regarding the short and long-term consequences of COVID-19 is still insufficient. This narrative review aims to provide information on the prolonged COVID-19 symptoms in recovered patients and their implications during dental management. Additionally, this manuscript highlights the oral manifestations of COVID-19 and its management. A systematic search was conducted in PubMed, Embase, Cochrane Library and Web of Science databases, WHO and CDC websites, and grey literature was searched through Google Scholar. Clinical articles (clinical trials, case-reports, cohort, and cross-sectional studies) were included, reporting prolonged post-COVID-19 symptoms. Although COVID-19 is an infectious disease primarily affecting the lungs, its multi-organ involvement is responsible for several prolonged symptoms, including oral implications. In recovered patients with prolonged COVID-19 symptoms, considerations for providing dental treatment has to be made as they can present with assortment of symptoms. These prolonged post-COVID-19 symptoms can affect the delivery of the required dental treatment. Hence, the recommendations proposed in this narrative review can be a useful starting point to aid dental teams providing adequate care for such recovered patients

Effects on gastric mucosa induced by dental bleaching – an experimental study with 6% hydrogen peroxide in rats

The value of aesthetic dentistry has precipitated several developments in the investigation of dental materials related to this field. The free marketing of these products is a problem and it is subject to various interpretations regarding its legality. There are several techniques for tooth whitening, the most used one being the external bleaching. It is the later version of such technique that poses the greatest danger of ingesting the product. The present study analysed the systemic effect of these products when they are swallowed.Objective This experimental study aimed to observe the effects of a tooth whitening product, whose active agent is 6% hydrogen peroxide, on the gastric mucosa of healthy and non-tumour gastric pathology animals.Material and Methods Fifty Wistar-Han rats were used and then distributed into 5 groups, one for control and four test groups in which the bleaching product was administered in animals with and without non-tumour gastric pathology (induced by the administration of 1 sample of 50% ethanol and 5% of drinking water during 6 days) at different times of study by gavage. There was a decrease in body weight in animals of groups handled during the study period, which was most pronounced in IV and VA groups. Changes in spleen weight relative to body weight revealed no statistically significant changes. An analysis of the frequency was performed on the results of macroscopic observation of the gastric mucosa.Results The gastric mucosa revealed lesions in all manipulated groups, being more frequent in groups III and IV. It appears that there is a synergism when using hydrogen peroxide and 50% ethanol in the same group.Conclusion Therefore, it seems that there are some signs of toxicity 3 to 4 days after administration of 6% hydrogen peroxide. The prescription of these therapies must be controlled by the clinician and the risks must be minimized

Evaluation of dentinogenesis inducer biomaterials: an in vivo study

When exposure of the pulp to external environment occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain pulp tissue vitality and function. These clinical situations require the use of materials that induce dentin repair and, subsequently, formation of a mineralized tissue. Objective: This work aims to assess the effect of tricalcium silicate cements and mineral trioxide aggregate cements, including repairing dentin formation and inflammatory reactions over time after pulp exposure in Wistar rats. Methodology: These two biomaterials were compared with positive control groups (open cavity with pulp tissue exposure) and negative control groups (no intervention). The evaluations were performed in three stages; three, seven and twenty-one days, and consisted of an imaging (nuclear medicine) and histological evaluation (H&E staining, immunohistochemistry and Alizarin Red S). Results: The therapeutic effect of these biomaterials was confirmed. Nuclear medicine evaluation demonstrated that the uptake of 99mTc-Hydroxymethylene diphosphonate (HMDP) showed no significant differences between the different experimental groups and the control, revealing the non-occurrence of differences in the phosphocalcium metabolism. The histological study demonstrated that in mineral trioxide aggregate therapies, the presence of moderate inflammatory infiltration was found after three days, decreasing during follow-ups. The formation of mineralized tissue was only verified at 21 days of follow-up. The tricalcium silicate therapies demonstrated the presence of a slight inflammatory infiltration on the third day, increasing throughout the follow-up. The formation of mineralized tissue was observed in the seventh follow-up day, increasing over time. Conclusions: The mineral trioxide aggregate (WhiteProRoot®MTA) and tricalcium silicate (Biodentine™) present slight and reversible inflammatory signs in the pulp tissue, with the formation of mineralized tissue. However, the exacerbated induction of mineralized tissue formation with the tricalcium silicate biomaterial may lead to the formation of pulp calcifications

What Is the Most Effective Technique for Bonding Brackets on Ceramic-A Systematic Review and Meta-Analysis

Background: There has been an increase in demand for orthodontic treatment within the adult population, who likely receive restorative treatments using ceramic structures. The current state of the art regarding the most effective method to achieve an appropriate bond strength of brackets on ceramic surfaces isn't consensual. This systematic review aims to compare the available surface treatments to ceramics and determine the one that allows to obtain the best bond strength. Methods: This systematic review followed the PRISMA guidelines and the PICO methodology was used, with the question "What is the most effective technique for bonding brackets on ceramic crowns or veneers?". The research was carried out in PubMed, Web of Science, Embase and Cochrane Library databases. In vitro and ex vivo studies were included. The methodological quality was evaluated using the guidelines for reporting of preclinical studies on dental materials by Faggion Jr. Results: A total of 655 articles searched in various databases were initially scrutinized. Sevety one articles were chosen for quality analysis. The risk of bias was considered medium to high in most studies. The use of hydrofluoric acid (HF), silane and laser afforded the overall best results. HF and HF plus laser achieved significantly highest bond strength scores in felsdphatic porcelain, while laser was the best treatment in lithium disilicate ceramics. Conclusions: The most effective technique for bonding brackets on ceramic is dependent on the type of ceramic

IN VITRO PHOTODYNAMIC THERAPY ON OCULAR MELANOMA CELLS

Purpose. To evaluate the effect of newly developed Ring-fused chlorins on cell proliferation of ocular melanoma. Methods. Human cell line MP-41 and a canine primary culture were subjected to the photosensitizers at concentrations between 0,5-1000 nM for 24 hours. The cells were irradiated with 10J (ƛ>570nm). Control groups included: untreated cells and cells submitted only to the administration vehicle (dimethylsulfoxide). The cytotoxicity (MTT) assessment was performed 24 hours after photodynamic therapy (PDT). Results. The dihydroxymethyl ring-fused chlorin (PS1) was the most active, with an IC50 value of 95.1 nM. The dihydroxymethyl-Pt(II) ring-fused chlorin (PS3) also showed promising photodynamic activity with an IC50 value of 114.8nM in MP-41 cells. These chlorins also showed highly satisfactory results in canine cells, with IC50 of 0.6nM for the PS1 and 2.2 nM for PS3. The dicarboxylic acid ring-fused chlorin (PS2) and dicarboxylic acid Pt(II) ring-fused chlorin (PS4) were less efficient in both ocular melanoma cells. PDT had a direct effect on ocular melanoma cell metabolic activity. High activity was obtained at very low concentrations. Conclusion. Satisfactory outcomes were achieved using new photosensitizers, particularly PS1 and PS3. The photosensitizers used are promising, particularly PS1 and PS3. This approach might become an option in treating eye melanoma in medicine and veterinary medicine. Supported by FCT, Portugal, SFRH/BD/139319/2018, SFRH/BD/116794/2016, UID/NEU/04539/2019, UIDB/04539/2020, UIDP/04539/2020 and POCI-01-0145-FEDER-007440. None

Localização subcelular do novo fotossensibilizador em células do melanoma ocular através de microscopia confocal

Introdução: O melanoma ocular é o objetivo de várias investigações em medicina e medicina veterinária devido à baixa taxa de resposta aos tratamentos conservadores convencionais1. A terapia fotodinâmica (PDT) é uma terapia mais conservadora para os tecidos não neoplásicos, que induz e ativa as vias de morte celular nos tecidos neoplásicos alvo2,3. O fotossensibilizador, luz e oxigenio são os três componentes vitais não tóxicos da reação fotodinâmica. Quando o fotossensibilizador é ativado por uma fonte de luz (600-800 nm), ocorre a produção de espécies reativas de oxigenio (ROS) que exerce efeito terapêutico sobre a neoplasia2. A oxidação irreversível leva à morte da célula tumoral por apoptose, necrose e autofagia2. A morte celular pode ser ativada pela via extrínseca, que envolve recetores da membrana plasmática, ou pela via intrínseca, em que a mitocôndria tem um papel central2,3. A localização subcelular dos fotossensibilizadores constitui o local de dano primário da terapia fotodinâmica e é determinante nas vias de atuação ativadas pela reação fotodinâmica3. Recentemente, desenvolvemos um grupo de novas clorinas, que são fotossensibilizadores muito eficazes em células de melanoma2,3,4. Dessa forma o objetivo do trabalho foi avaliar a localização subcelular (núcleo e mitocôndria) da nova clorina em células do melanoma ocular. Métodos: Células da linha celular de melanoma ocular (MP-41) cultivadas em meio RPMI com 25% de FBS, foram semeadas em placas de 24 poços com lamelas esterilizadas. As células foram incubadas com 500 nM da nova clorina (derivado dihidroximetilo de 4,5,6,7-tetra-hidropirazolo[1,5-a]piridina fundido com tetrafenilclorina) por 24 h. Após este período, as culturas foram submetidas a duas lavagens com PBS, de modo a remover todo o fotossensibilizador no exterior das células, e procedeu-se à marcação dos organelos. As células que foram marcadas com o corante nuclear Hoechst 33252 (blue) e incubadas com uma solução de 5 μg/ml da sonda em PBS durante 15 minutos no escuro. As culturas celulares que foram marcadas com a sonda mitocondrial MitoTracker® Green FM foram incubadas com uma solução de 200 nM da sonda em PBS durante 30 minutos, a 37ºC, no escuro. Após as incubações com as respetivas sondas as células foram lavadas com PBS as lamelas foram montadas sobre lâminas e observadas ao microscópio confocal (Carl Zeiss MicroImaging LSM710, objetiva 40X) e fotografadas. As imagens foram analisadas no software ImageJ e a colocalização avaliada pelo coeficiente de correlação de Pearson. Resultados: Os estudos de localização subcelular confirmaram a internalização celular do novo fotossensibilizador. A média para coeficiente de Pearson foi -0,114 para colocalização núclear, certificando a existência 43% de correlação negativa, para as imagens analisadas, demostrando que não ocorre internalização nuclear do novo fotossensibilizador. No que respeita a mitocôndria, verificou-se a existência de 66%, correlação de Pearson positiva, que foi igual a média 0,366 para as imagens analisadas, demostrando que ocorre internalização mitocondrial do novo fotossensibilizador. Conclusão: Verificou-se que o novo fotossensibilizador é captado pelas células de melanoma ocular e que se acumula nas mitocôndrias, mas não penetra no núcleo celular

Isolation and Identification of Cytotoxic Compounds Present in Biomaterial Life®

Direct pulp capping consists of a procedure in which a material is directly placed over the exposed pulp to maintain dental vitality. Although still widely used in clinical practice, previous in vitro studies found that the biomaterial Life® presented high cytotoxicity, leading to cell death. This study aimed to identify the Life® constituents responsible for its cytotoxic effects on odontoblast-like cells (MDPC-23). Aqueous medium conditioned with Life® was subjected to liquid-liquid extraction with ethyl acetate. After solvent removal, cells were treated with residues isolated from the organic and aqueous fractions. MTT and Trypan blue assays were carried out to evaluate the metabolic activity and cell death. The organic phase residue promoted a significant decrease in metabolic activity and increased cell death. On the contrary, no cytotoxic effects were observed with the mixture from the aqueous fraction. Spectroscopic and spectrometric methods allowed the identification of the toxic compounds. A mixture of the regioisomers ortho, para, and meta of N-ethyl-toluenesulfonamide was identified as the agent responsible for the toxicity of biomaterial Life® in MDPC-23 cells. These findings contribute to improving biomaterial research and development

Microleakage Assessment Techniques: a Scoping Review

Scoping Revie

10-MDP Based Dental Adhesives: Adhesive Interface Characterization and Adhesive Stability—A Systematic Review

The incorporation of functional monomers in dental adhesive systems promotes chemical interaction with dental substrates, resulting in higher adhesion forces when compared to micromechanical adhesion only. The 10-MDP monomer, whose chemical structure allows for a polar behavior which is favorable to adhesion, also promotes the protection of collagen fibers through the formation of MDP-calcium salts. This systematic review aimed to characterize the interface created by 10-MDP containing adhesive systems through an evaluation of the following parameters: Formation of nano-layered structures, capacity to produce an acid-base resistant zone, and adhesion stability. The research was conducted using PubMed, Cochrane Library, Web of Science and Embase, limited to English, Spanish, and Portuguese articles. The research was done according to the PICO strategy. The 10-MDP monomer has the capacity to produce an acid-base resistant zone on the adhesive interface, which increases the response to acid-base challenges. The adhesion established by these systems is stable over time. To have the best of these adhesive solutions, a scrubbing technique must be used to apply the adhesive system on dental substrates, in order to improve monomers infiltration and to create a stable bond. Time must be given for the solution to infiltrate, hybridize and form the MDP-Ca, improving adhesive stability