Citotoxicidade de três cimentos resinosos fotopolimerizáveis sobre fibroblastos 3T3

Introduction: Light-cured resin cements are the first choice for the cementation of laminate veneers. Ideally, they should be biocompatible and offer minimum risks to patients. Objective: The aim of this study was to evaluate, in vitro, the cytotoxicity of three resin cements: Variolink II, Ivoclar Vivadent (C1), Allcem Veneer, FGM (C2), and Rely X Veneer, 3M ESPE (C3). Material and method: Twenty four samples of each of the cements were fabricated in a standardized metal mold, light activated, and transferred to a 96-well cell plate with culture of fibroblasts. After 24, 48, and 72h of incubation, cytotoxicity was assessed and cell viability was calculated by the methyl-thiazol-tetrazolium (MTT) colorimetric assay. Absorbance was measured at 570 nm using a microplate spectrophotometer. Result: The following results were found: Variolink II presented viability of 72.24% (SD 6.80) after 24h, 83.92% (SD 5.26) after 48h, and 92.77% (SD 5.59) after 72h; Allcem Veneer exhibited viability of 70.46% (SD 12.91) after 24h, 85.03% (SD 21.4) after 48h, and 70.46% (SD 12.91) after 72h; Rely X Veneer showed viability of 5.06% (SD 0.88) after 24h, 5.84% (SD 1.18) after 48h, and 6.99% (SD 1.34) after 72h. Conclusion: Under these testing conditions, Rely X Veneer presented significantly higher cytotoxicity compared with those of the other light-cured resin cements assessed.Introdução: Cimentos resinosos fotopolimerizáveis são materiais de eleição para a cimentação de facetas laminadas. Devem ser biocompatíveis oferencendo riscos mínimos ao uso clínico em pacientes. Objetivo: O objetivo desse trabalho foi avaliar in vitro a citotoxicidade de três cimentos resinosos: Variolink II (Ivoclar Vivadent), Allcem Veneer, (FGM) e Rely X Veneer (3M ESPE). Material e método: Vinte e quatro corpos de prova de cada cimento foram confeccionados em matrizes metálicas padronizadas e inseridos em placa de cultura de células de noventa e seis poços contendo fibroblastos da linhagem 3T3. As células foram cultivadas em meio de cultivo celular RPMI 1640 com 5% de soro fetal bovino, com 0,1% de penicilina/estreptomicina em estufa a 37°C, em atmosfera úmida com 5% de CO2. O grau de citotoxicidade de cada cimento foi avaliado após os tempos de contato de 24h, 48h e 72h através do método MTT (3-(4,5-dimetiltiazol-2yl)-2,5- difenil brometo de tetrazolina), que avalia a viabilidade celular pela função mitocondrial. Após os tempos estabelecidos, as amostras foram removidas, tratadas e levadas ao espectofotômetro de microplaca para leitura da absorbância em 570nm. Resultado: O cimento Variolink apresentou em 24h viabilidade de 72,24% (±6,80), em 48h de 83,92% (± 5,26) e de 92,77% (±5,59) em 72h. Allcem Veneer apresentou viabilidade de 70,46% (± 12,91) em 24h; 85,03% (± 21,4) em 48h e 70,46% (± 12,91) em 72h. O RelyX Veneer demonstrou viabilidade de 5,06% (± 0,88) em 24h; 5,84% (± 1,18) em 48h e 6,99% (± 1,34) em 72h. Conclusão: Estes resultados demonstraram que o cimento Rely-X se apresentou significativamente mais citotóxico nas condições testadas

Cytotoxicity evaluation of two root canal sealers and a commercial calcium hydroxide paste on THP1 cell line by Trypan Blue assay

OBJECTIVE: The aim of this investigation was to evaluate the cytotoxicity of two brands of root canal sealers, epoxy-resin based and zinc oxide-eugenol based, and one commercial calcium hydroxide paste on a monocyte cell line THP-1. MATERIAL AND METHODS: Undiluted (crude extract) and diluted extracts to 10%, 1%, 0.1%, 0.01%, 0.001% and 0.0001% of the sealers were tested for cytotoxicity to THP-1 cells using the trypan blue assay. Extracts were obtained according to ISO standard. Data were analyzed statistically by the Kruskal-Wallis and Mann-Whitney tests at 5% significance level. RESULTS: Crude extract of AH Plus and Fill Canal killed approximately 90% of THP-1 cells versus 36% of THP-1 cells killed by L&C crude extract (

Antimicrobial activity of per acetic acid for trans-operative disinfection of endodontic files

Reducing the accumulation of microorganisms on an endodontic file during endodontic treatment is important to limit recontamination of the root canal and increase likelihood of successful treatment outcome. Objective: To compare the antimicrobial activity of peracetic acid (PA), isopropyl alcohol and acetone against a range of bacteria and also for disinfection of contaminated endodontic K-files. Material and Methods: Antimicrobial activities of PA, isopropyl alcohol and acetone were compared against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, vancomycin resistant E. faecalis (VRE) and meticillin resistant S. aureus (MRSA), using minimum bactericidal concentration (MBC) and time-kill assays. Test solutions at different exposure times (15 s and 30 s) were assessed for treatment of endodontic files acting as carriers of E. faecalis-contaminated dental debris. Results: All bacteria were susceptible to PA (MBC range 0.25-1%), acetone (MBC range 50-60%) and isopropyl alcohol (30-40%). Using a time-kill assay of the antimicrobials at the determined MBC, all test microorganisms, with the exception of E. faecalis (VRE) 7766 were killed after 15 s exposure. In the case of E. faecalis 7766, viable cells remained detectable after 120 s exposure to acetone. Testing disinfection of endodontic K-files, previously coated with dental debris containing E. faecalis, it was found that PA (2%) completely killed E. faecalis after 15 s exposure. However, even after 30 s exposure, isopropyl alcohol (80%) and acetone (80%) had limited disinfecting activity. Conclusion: Extrapolation of these results to clinical practice would suggest that PA would be the most effective agent for trans-operative disinfection of endodontic K-files during treatment of a single patient

Avaliação da expressão de citocinas pró e antiinflamatórias e fatores de crescimento após estimulação com diferentes agentes de irrigação

No endodontic auxiliary chemical solutions fills all the requirements considered ideal, especially for biocompatibility, since all solutions used have some degree of cytotoxicity. The aim of this study was to investigate the effect of auxiliary chemical solutions; sodium hypochlorite 5.25% (NaOCl), chlorhexidine 2% (CHX), chitosan 0.2%, etidronic acid 18% (HEBP) and grape seed extract 6.5% (GSE); in subcytotoxic concentrations, on the expression of pro and anti-inflammatory cytokines, when in contact with human lymphoma lineage, differentiated into human macrophages, “human macrophage-like” U937. The cytotoxic and subcytotoxic concentrations of each solution were determined using mouse cells fibroblasts (L929), by the MTT cell viability test. The subcytotoxic concentrations, of the auxiliary chemical solutions, were maintained in contact with the U937 cells and the expression of 7 pro-inflammatory cytokines were analyzed. The substance with the lowest cytotoxic activity was the GSE, followed by HEBP, NaOCL, CHX and chitosan. The HEBP was a chemical agent that showed better results in modulating the expression of pro-inflammatory cytokines, but all the auxiliary chemical substances were able to induce the expression of various pro-inflammatory cytokines.Nenhuma solução química auxiliar endodôntica preenche todos os requisitos considerados ideais, especialmente para a biocompatibilidade, uma vez que todas as soluções utilizadas possuem algum grau de citotoxicidade. O objetivo deste estudo foi investigar o efeito de soluções químicas auxiliares; hipoclorito de sódio 5,25% (NaOCl), clorexidina 2% (CHX), quitosana 0,2%, ácido etidrônico 18% (HEBP) e extrato de semente de uva 6,5% (GSE); em concentrações sub-citotóxicas, na expressão de citocinas pró e antiinflamatórias, quando em contato com a linhagem de linfoma humano, diferenciadas em macrófagos humanos, “human macrophage-like” U937. As concentrações citotóxicas e subitotóxicas de cada solução foram determinadas usando fibroblastos de células de camundongo (L929), pelo teste de viabilidade celular MTT. As concentrações subitotóxicas, das soluções químicas auxiliares, foram mantidas em contato com as células U937 e a expressão de 7 citocinas pró-inflamatórias foi analisada. A substância com menor atividade citotóxica foi o GSE, seguida por HEBP, NaOCL, CHX e quitosana. O HEBP foi um agente químico que apresentou melhores resultados na modulação da expressão de citocinas pró-inflamatórias, mas todas as substâncias químicas auxiliares foram capazes de induzir a expressão de várias citocinas pró-inflamatórias

Antimicrobial activity of different concentrations of NaOCl and chlorhexidine using a contact test

The purpose of this study was to analyze the in vitro antimicrobial activity of sodium hypochlorite (1% and 5%) and chlorhexidine (0.12%, 0.5% and 1%). Bacterial samples (ATCC) of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Porphyromonas gingivalis and Fusobacterium nucleatum were submitted to a contact test. Solutions were evaluated at different time intervals: immediately, 5 min, 15 min, and 30 min after contact and repeated 10 times. The results of the contact test showed that 0.12% chlorhexidine did not eliminate E. faecalis at any time interval, while 0.5% and 1% chlorhexidine and 1% and 5% sodium hypochlorite did. These results permit us to conclude that to obtain better antimicrobial activity, chlorhexidine in a concentration greater than 0.12% should be used

Antimicrobial resistance and virulence traits of Enterococcus faecalis from primary endodontic infections

Objectives To determine the phenotypic and molecular characteristics of Enterococcus faecalis recovered from primary endodontic infections in Brazilian patients. Methods Twenty isolates of E. faecalis recovered from 43 Brazilian patients with primary endodontic infections were identified by biochemical profiling (API20Strep) and 16S rDNA sequencing. Antimicrobial susceptibility was ascertained by agar dilution, using the recommended protocol of the Clinical and Laboratory Standards Institute (CLSI). PCR with validated primers was used to detect genes associated with antibiotic resistance and specific virulence factors. Results All isolates were deemed susceptible to penicillin G, erythromycin and vancomycin. However, nine isolates had a minimum inhibitory concentration of 4μg/mL to vancomycin (the resistance breakpoint). Fourteen isolates (70% of isolates) were also resistant to tetracycline with MICs of >64μg/mL. PCR products for tetracycline resistance genes were detected in test isolates, while erythromycin and vancomycin resistance genes were not evident. Gelatinase, aggregation substance and enteroccocal surface protein genes were detected in 20, 18 and 12 isolates, respectively. Conclusions Endodontic E. faecalis isolates exhibit high level of resistance to tetracycline, an antibiotic that has use in local treatment of dental infections. This opens up a much-needed debate on the role and efficacy of this antibiotic for oral infections. Furthermore, these isolates were shown to possess genes that could contribute to pathogenicity in the pulp cavity

Efecto antimicrobiano de la terapia fotodinámica sobre Enterococcus faecalis, estudio in vitro.

OBJETIVO: Evaluar el efecto antibacteriano, in vitro, de la Terapia Fotodinámica (PDT) sobre Enterococcus faecalis. MATERIAL Y MÉTODOS: Fueron preparadas suspensiones bacterianas a partir de cepas clínicas de E. faecalis. Estas suspensiones fueron divididas en tres grupos experimentales (1L, 2L y 3L) y un grupo control (GC). Utilizando un equipo Twin Laser conteniendo como medio activo un diodo de GaAIAs, los grupos experimentales recibieron respectivamente dosis de energía de 1 min a 60 J/cm2, 2 min a 120 J/cm2 y 3 min a 180 J/cm2. Las suspensiones fueron diluidas, sembradas e incubadas para posterior contaje de Unidades Formadoras de Colonia por mL (UFC/mL). Los valores de UFC fueron analizados estadísticamente por ANOVA y test de Tukey (p<0,05). RESULTADOS: Los grupos 1L, 2L y 3L mostraron una reducción de 99,88%, 99,86% y 99,92% respectivamente. Siendoque esta reducción de UFC/mL fue estadísticamente signifi cativa  (p<0,05). Sin embargo, no fueron encontradas diferencias signifi cativas entre los tres grupos experimentales, sometidos a diferentes tiempos de PDT (p>0,05). CONCLUSIÓN: La PDT es una alternativa efi caz para la eliminación de E. faecalis, microorganismo frecuentemente asociado a casos de fracaso endodóntico.