Development of multiparticulate systems based on natural polymers for morin controlled release.

This study aimed to develop a multiparticulate system based on sodium alginate/gellan gum polymers for morin controlled release using standardized spray-dryer parameters. A 24 experimental factorial design was used to standardize spray-dryer parameters. After standardization, three systems with three different proportions of the natural polymers (50:50, 25:75, 75:25; sodium alginate: gellan gum) with and without morin (control) were developed. The systems were characterized according to its morphology and physicochemical properties. Next, the systems were evaluated regarding antibiofilm and antimicrobial activity against Streptococcus mutans. The factorial design indicated the use of the following parameters: i) air flow rate: 1.0 m3 /min; ii) outlet temperature: 120 °C; iii) natural polymers combination in different proportions; iiii) polymer concentration: 2 %. Scanning electron microscopy showed microparticles with spherical shape and rough surface. The samples released 99.86 % ± 9.36; 85.45 % ± 8.31; 86.87 % ± 3.83 of morin after 480 min. The systems containing morin significantly reduced S. mutans biofilm biomass, microbial viability and acidogenicity when compared to their respective controls. In conclusion, the spray-dryer parameters were standardized to the highest possible yield values and proved to be efficient for morin encapsulation and controlled release. Furthermore, these systems controlled important virulence factors of S. mutans biofilms.

Establishment of a saliva donor selection for in vitro biofilm growth / Seleção de doadores de saliva para crescimento de biofilme in vitro

Introdução: O emprego de biofilmes polimicrobianos, utilizando a saliva como inóculo, é um modelo promissor para o estudo de biofilmes cariogênicos in vitro. Entretanto, ainda não existe uma padronização para seleção de doadores de saliva. Objetivo: O objetivo deste estudo foi estabelecer uma metodologia para seleção de doadores de saliva utilizando fatores salivares microbianos e características in vitro do biofilme. Material e método: Para doação de saliva foram selecionados vinte voluntários. Os voluntários permaneceram 24 horas sem escovar os dentes e ficaram em jejum por 2 horas antes da coleta da saliva. Foram avaliados os seguintes parâmetros: viabilidade das bactérias anaeróbias totais e mutans streptococci; concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM) da clorexidina; capacidade de formação de biofilme por meio da biomassa; e a suscetibilidade dos biofilmes à clorexidina. Resultado: A viabilidade bacteriana da saliva, a capacidade de formação de biofilme e a suscetibilidade do biofilme à clorexidina foram apresentadas como média e intervalo de confiança (95%). A diferença entre a viabilidade do biofilme (mutans streptococci e bactérias totais) após tratamento com NaCl 0,9% e diacetato de clorexidina 0,2% foi comparada pelo teste t de Student com nível de significância estabelecido em 5%. A viabilidade total de bactérias anaeróbias (mediana) foi de 7,28 log 1+UFC/mL (unidades formadoras de colônia/mL). A viabilidade dos mutans streptococci na saliva apresentou mediana de 5,47 log 1+UFC/mL. Para capacidade de formação de biofilme a mediana da biomassa foi de 0,1172 A570. Conclusão: O tratamento com clorexidina reduziu significativamente os mutans streptococci e a viabilidade total das bactérias. A metodologia para seleção do doador de saliva foi estabelecida com sucesso.

Introduction: The utilization of polymicrobial biofilms, with saliva as an inoculum, represents a promising model for in vitro studies on cariogenic biofilms. However, there is still no standardization for selecting saliva donors. Objective: The aim of this study is to establish a methodology for the selection of saliva donors using microbial salivary factors and in vitro biofilm characteristics. Material and method: For saliva donation, twenty volunteers were selected. Volunteers remained 24 h without brushing their teeth and fasted for 2 h before saliva collection. The following parameters were evaluated: total anaerobic bacteria and mutans streptococci viability; minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC) of chlorhexidine; biofilm forming capacity by biomass assessment; and the susceptibility of biofilms to chlorhexidine. Result: Saliva bacterial viability, biofilm forming capacity and biofilm susceptibility to chlorhexidine were presented as mean and confidence interval (95%). The difference between biofilm (mutans streptococci and Total bacteria) viability after treatment with NaCl 0.9% and 0.2% chlorhexidine diacetate was compared using the Student t-test with a significance level established at 5%. Total anaerobic bacteria viability (median) was 7.28 log 1+CFU/mL (colony forming units/ mL). Mutans streptococci viability in the saliva showed a median of 5.47 log 1+CFU/mL. Biofilm forming capacity showed that biomass had a median of 0.1172 A570. Conclusion: Treatment with chlorhexidine significantly reduced mutans streptococci and total bacteria viability. The methodology for the selection of the saliva donor was successfully established.

Effect of the technique of photodynamic therapy against the main microorganisms responsible for periodontitis: A systematic review of in-vitro studies.

OBJECTIVE: The present study aimed to conduct a systematic review of the literature, to evaluate, in vitro, the effectiveness of the technique of photodynamic therapy against microorganisms associated with periodontal disease. DESIGN: This systematic review was carried out in accordance with the items on the PRISMA checklist and Cochrane guidelines. Only in vitro studies that evaluated the effect of the technique of antimicrobial photodynamic therapy on periodontopathogenic microorganisms were included. RESULTS: A total of 32 articles published between 2000 and 2021 were included for qualitative analysis. For microorganisms in suspension, 25 studies (78.12%) showed a reduction greater than or equal to 3 logs CFU/mL of species associated with periodontal disease. In biofilms, three studies (42.7%) showed a reduction greater than or equal to 3 logs CFU/mL. CONCLUSIONS: The results showed that the technique of photodynamic therapy may be a promising alternative to conventional antimicrobial approaches for reducing bacteria closely associated with periodontal disease. Some parameters (pre-irradiation time, type of photosensitizer, standardization of light parameters) need to be better established before conducting clinical studies.

Antimicrobial photodynamic therapy mediated by methylene blue coupled to ß-cyclodextrin reduces early colonizing microorganisms from the oral biofilm.

OBJECTIVE: To test the effect of antimicrobial photodynamic therapy (A-PDT) on the oral biofilm formed with early colonizing microorganisms, using the photosensitizer methylene blue coupled with ß-cyclodextrin nanoparticles and red light sources laser or LED (λ =660 nm). METHODS: The groups were divided into (n = 3, in triplicate): C (negative control, 0.9 % NaCl), CX (positive control, 0.2 % chlorhexidine), P (Photosensitizer/Nanoparticle), L (Laser), LED (light-emitting diode), LP (Laser + Photosensitizer/Nanoparticle) and LEDP (LED + Photosensitizer/Nanoparticle). A multispecies biofilm composed ofS. gordonii, S. oralis, S. mitis, and S. sanguinis was grown in microplates containing BHI supplemented with 1% sucrose (w/v) for 24 h. Light irradiations were applied with a laser at 9 J for 90 s (320 J/cm2), or with LED, at 8.1 J for 90 s (8.1 J/cm2). The microbial reduction was assessed by counting viable biofilm microorganisms in selective culture media, before and after the treatments. Data normality was assessed by the Shapiro-Wilk test, and the results were submitted to Kruskal-Wallis analysis, followed by Dunn's test, with a significance level of 5%. RESULTS: The groups LP and LEDP were able to significantly reduce the biofilm microorganism counts by as much as 4 log10 times compared to the negative control group (p < 0.05) and did not statistically differ from the positive control group (CX) (p > 0.05). CONCLUSION: The A-PDT mediated by encapsulated ß-cyclodextrin methylene blue irradiated by Laser or LED was effective in the microbial reduction of multispecies biofilm composed of early colonizing microorganisms.

COVID-19 (SARS-CoV-2) infection and thrombotic conditions: A systematic review and meta-analysis.

BACKGROUND: COVID-19 is an infectious disease caused by SARS-CoV-2 associated with haematological manifestations (thrombolytic events). AIMS: Considering the high prevalence of the thrombotic scenarios associated with COVID-19, the aim of this study was to perform a systematic review of the available literature, concerning the relation of COVID-19 and the thrombotic events, and identify prognostic factors for these events. MATERIALS & METHODS: PubMed, Web of Science and Scopus databases were searched. Independent reviewers conducted all flow diagram steps. For qualitative analysis, Oxford level of evidence and Newcastle-Ottawa scale were used in the eligible articles. For the prognostic factors, a meta-analysis was conducted to age, number of neutrophils and platelets, and levels of ferritin, C-reactive protein, lactate dehydrogenase and D-dimer. Publication bias was accessed by funnel plot and by trim-and-fill test. Trim-and-fill test was also applied to evaluate meta-analysis bias. RESULTS: Twenty articles were included in the qualitative analysis, and 6 articles were included in the meta-analysis. Case-control studies showed bias related to exposure, and the main bias in cohort studies were related to selection and outcome. All articles received score 4 for the level of evidence. Hypertension and diabetes were the comorbidities more frequently associated with thrombolytic events. Significant results were found regarding D-dimer (P < .0001) and age (P = .0202) for thrombotic events in patients diagnosed with COVID-19. CONCLUSION: Patients older than 60 years, with hypertension, diabetes and D-Dimer values above 3.17 µg/mL, can be considered prognostic factors for developing thrombotic events due to COVID-19.

Combined effect of starch and sucrose on carbonic anhydrase VI activity in saliva and biofilm of children with early childhood caries. Exposure to starch and sucrose alters carbonic anhydrase VI activity in saliva and biofilm.

OBJECTIVES: This study aimed to investigate whether combined exposure to starch and sucrose modifies the activity of carbonic anhydrase VI (CA VI) in saliva (Study 1) and biofilm (Study 2) of children with early childhood caries (ECC). MATERIAL AND METHODS: For Study 1 and Study 2, respectively, 54 and 46 preschoolers aged 4 to 5 were allocated into two groups: caries-free (CF) and with ECC. Children were exposed to rinses with sucrose, starch, and sucrose plus starch solutions. CA VI activity, pH, and buffering capacity (BC) were evaluated in saliva and biofilm. RESULTS: In Study 1, a significant reduction in saliva pH was observed after sucrose and sucrose plus starch rinses. CA VI activity was influenced by ECC independently of the type of carbohydrate to which children were exposed. CA VI activity was higher in children with ECC; however, after rinses, CA VI activity was reduced. In Study 2, biofilm pH and BC were reduced after rinses with sucrose and sucrose plus starch. CA VI activity was significantly high before rinse in ECC group when compared with CF group; however, no difference was observed between groups after rinses. CONCLUSIONS: In saliva, exposure to starch and sucrose (isolated or combined) induced a reduction in CA VI activity in children with ECC. In biofilm, the combination of starch and sucrose did not modify CA VI activity in ECC children. CLINICAL RELEVANCE: The responsivity of the CA VI reflects directly in important parameters related to the pH maintenance on the oral cavity.

Influence of the Vehicle on the Tissue Reaction and Biomineralization of Fast Endodontic Cement

ABSTRACT Objective: To investigate the tissue response and the biomineralization ability of CER prepared with epoxy resin or water compared to Mineral Trioxide Aggregate (MTA). Material and Methods: Polyethylene tubes containing materials or empty tubes for control were inserted into the subcutaneous tissues of 30 rats. After 7, 15, 30, 60, and 90 days, the rats were killed and the tubes were removed for analysis using hematoxylin-eosin staining, von Kossa staining, and under polarized light. Inflammation was graded through a score system; the thickness of the fibrous capsule was classified as thin or thick; the biomineralization ability was recorded as present or absent. The results were statistically analyzed using the Kruskal-Wallis test (p<0.05). Results: Histologic analysis performed after 7 and 15 days for CER prepared with epoxy resin or water and for MTA showed moderate inflammation and a thick fibrous capsule (p>0.05). After 30, 60, and 90 days, mild inflammation, and a thin fibrous capsule were observed in all groups (p>0.05). Conclusion: All materials had structures positive for von Kossa and birefringent to polarized light. CER epoxy resin showed biocompatibility and biomineralization similar to CER water and MTA.

Addition of hydrogen peroxide to methylene blue conjugated to ß-cyclodextrin in photodynamic antimicrobial chemotherapy in S. mutans biofilm.

OBJECTIVE: This study evaluated the effect of hydrogen peroxide addition on ß-cyclodextrin-conjugated methylene blue in antimicrobial photodynamic therapy(a-PDT) in S. mutans biofilm model using laser or light emitting diode (LED) (λ = 660 nm). METHODS: A preliminary assay was performed to evaluate the cytotoxicity of hydrogen peroxide in oral fibroblasts by the colorimetric method (MTT). Afterwards, groups were divided into (n = 3, in triplicate): C (negative control), CX - chlorhexidine 0.2% (positive control), P (methylene blue/ß-cyclodextrin), H (Hydrogen Peroxide at 40 µM), PH, L (Laser), LP, LH (Laser+Hydrogen Peroxide), LPH, LED, LEDP, LEDH, and LEDPH. The biofilm was formed in 24 h with BHI + 1% sucrose (w/v). Light irradiations were conducted with laser, 9 J, 323 J/cm2, 113 s or with LED, 8.1 J, 8.1 J/cm2 for 90 s. Microbial reduction was evaluated by counting the viable microorganisms of the biofilm after the respective treatments, in a selective culture medium, and laser confocal microscopy evaluation. RESULTS: LP, LH, LPH, LEDP, LEDH, and LEDPH groups statistically reduced the counts of S.mutans compared with the C group and the log reductions were of 1.87, 1.94, 2.19, 0.91, 0.92, and 1.33, respectively; the addition of hydrogen peroxide did not potentiate the microbial reductions (LPH and LEDPH) compared with the LP and LEDP groups. CONCLUSION: The association of hydrogen peroxide with the conjugated ß-cyclodextrin nanoparticle as photosensitizer did not result in an enhanced effect of a-PDT; hydrogen peroxide behaved as a photosensitizer, since it reduced the number of S. mutans when associated with laser light.