Thiourethane-functionalized fillers: biological properties and degradation resistance

Abstract This study determined the effect of thiourethane-functionalized fillers (TU) on the antimicrobial properties, cytotoxicity, degree of conversion (DC), water sorption (Wsp) and solubility (Wsl) of experimental composites. TU-modified fillers were added at different ratios in experimental composites: 0 (Control-TU0), 25% (TU25), 50% (TU50), 75% (TU75) and 100wt% (TU100). The antimicrobial properties were detected through the exhaustion test and counting of Streptococus mutans colonies for biofilm formation. Cytotoxicity to human gingival fibroblasts was evaluated in three different parameters: XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide), NRU (Neutral Red Uptake assay) and CVDE (Crystal Violet Dye Exclusion test)) at the same cells. ELISA was used to measure the IL-6 and b-FGF biomarkers. DC was determined by Fourier-transformed infrared spectroscopy, while Wsp and Wsl by mass variations. Inhibitory capacity of biofilm formation was not observed for any material. All groups presented at least 70% of cell survival within the observed periods (24h and 7 days). Positive control (toxic) had high IL-6 values and low b-FGF values. No significant variations in DC, Wsp, and Wsl were observed among the experimental groups. The use of thiourethane did not present antimicrobial and cytotoxic activity and the tested materials presented equivalent properties to those conventionally used in dentistry.

A Preliminary Research Study on the Cytotoxicity of Expired and Non-expired Composite Resins: In Vitro Study / Estudio preliminar in vitro de la citotoxicidad de resinas compuestas caducadas y no caducadas

Astracts Objective: Studies have focused on use of non-expired composites. Unfortunately some clinicians still use expired composite resins without considering their effects. The objective of this in vitro preliminary research was to investigate cytotoxicity of expired(6-months) and non-expired composite resins. Materials and methods: Expired (E) and non-expired (NE) samples of one bulk-fill (Tetric N-Ceram Bulk-fill (TNB), Ivoclar Vivadent), two nano-hybrid (Tetric N-Ceram (TN), Ivoclar Vivadent; Clearfil Majesty ES-2 (CM), Kuraray) composite resins were tested on L929 fibroblast cells. Medium covering cells was removed then plastic rings (2-mm height) were filled with non-polymerized composite resins, placed in direct contact with cells and polymerized with LED light curing unit (LCU). Three samples were prepared for each group. After polymerization, removed medium was added to the cells. Cells that were left without medium (WOM) and cells that were exposed to LCU were used as positive control groups. Cells without any treatment were used as negative control group (C). Cells were incubated with tested materials for 7-days to evaluate cytotoxicity. Cell viability was calculated by sulforhodamine B test as a percentage (%). One-way ANOVA and post-hoc Tukey tests were used for statistical analyses (p0.05), except between TN NE and TN E (p0.05). All experimental groups compared with C group showed statistically significant cytotoxicity (p<0.05). A statistically significant difference existed between LCU and C groups (p<0.05). Conclusions: In clinical practice, expired composite resins should never be used. Although a correlation was found between expiration dates of nano-hybrid composite resins and cell viability, opposite data were obtained for bulk- fill composite resin. Researches are still required to evaluate biocompatibility of bulk- fill composite resins at various thicknesses with current LCUs.

Resumen Objetivo: Los estudios se han concentrado en el uso de resinas compuestas no vencidos. Desafortunadamente, algunos clínicos aún usan resinas caducadas sin considerar sus efectos. El objetivo de este estudio preliminar in vitro fue investigar la citotoxicidad de resinas compuestas caducadas (6 meses) y no caducadas. Materiales y métodos: muestras caducadas (E) y no caducadas (NE) de una resina bulk-fill (Tetric N-Ceram Bulk-fill (TNB), Ivoclar Vivadent) y dos resinas nanohíbridas (Tetric N-Ceram (TN) Ivoclar Vivadent) (Clearfil Majesty ES-2 (CM), Kuraray), se probaron en células de fibroblastos L929. Se retiraron las células que cubrían el medio, luego se llenaron anillos de plástico (2 mm de altura) con resinas no polimerizadas, se colocaron en contacto directo con las células y se polimerizaron con una unidad de fotocurado LED (LCU). Se prepararon tres muestras para cada grupo. Después de la polimerización, se añadió el medio eliminado a las células. Las células que quedaron sin medio (WOM) y las células que se expusieron a LCU se usaron como grupos de control positivo. Las células sin ningún tratamiento se utilizaron como grupo de control negativo (C). Las células se incubaron con las resinas durante 7 días para evaluar la citotoxicidad. La viabilidad celular se calculó mediante la prueba de sulforodamina B como un porcentaje (%). ANOVA unidireccional y pruebas post-hoc de Tukey se utilizaron para los análisis estadísticos (p 0.05), excepto entre TN NE y TN E (p 0.05). Todos los grupos experimentales en comparación con el grupo C mostraron citotoxicidad estadísticamente significativa (p <0,05). Existió una diferencia estadísticamente significativa entre LCU y grupos C (p <0.05). Conclusiones: En la práctica clínica, las resinas compuestas caducadas nunca deben usarse. Aunque se encontró una correlación entre las fechas de vencimiento de las resinas compuestas nano-híbridas y la viabilidad celular, se obtuvieron datos opuestos para la resina bulk-fill. Se requieren nuevas investigaciones para evaluar la biocompatibilidad de las resinas bulk-fill en distintos espesores con las LCU actuales.

Evaluating of cytotoxic effects of highly esthetic dental composites / Avaliação dos efeitos citotóxicos de resinas compostas altamente estéticas

Objective: Dental composites developed by using nanotechnology in the field of dentistry are widely used in the treatment of anterior and posterior teeth. This study aimed to investigate the cytotoxic effects of dental composites of different particle size on L929 mouse fibroblast cell line by extract test method in vitro. Material and Methods: Composite samples of 8 x 2 mm diameter were prepared by polymerizing with led light device by using glass mod in a sterile cabinet. Composite samples of which surface areas were calculated according to ISO standards (3 cm2 / ml), were incubated for 24 and 72 hours, at 37 o C. cell viability was assessed by 3-[4,5-dimethylthiazole-2- yl]-2,5-diphenyltetrazolium bromide (MTT) assay and cell death was evaluated by the lactate dehydrogenase (LDH) leakage assay. Results: The 1:1 extracts of the composites at the end of 24 hours (except for nanoceramic composite) showed no toxic effect. When the cell viability results of the 1:1 extracts of the composite samples at the end of 72 hours were statistically analyzed, significant differences were found comparing to the control group (p < 0.05). Conclusion: It was observed that the type and size of the filler were effective on the toxicity of the composites, and the composites containing Bis-GMA, TEGDMA, UDMA and Bis EMA monomers in their organic matrix showed acceptable cell viability (70%) as specified by ISO. However, the composites with PEGDMA and BPA monomers in their organic matrix showed poor cell viability, which is below the acceptable level of 70%, and were found to have a toxic effect. (AU)

Objetivo: As resinas compostas desenvolvidas pela nanotecnologia no campo da odontologia são amplamente utilizadas no tratamento de dentes anteriores e posteriores. Este estudo teve como objetivo investigar os efeitos citotóxicos de resinas compostas de diferentes tamanhos de partículas na linha celular de fibroblastos de camundongos L929 pelo método de teste de extrato in vitro. Material e Métodos: Amostras compostas de 8 x 2 mm de diâmetro foram preparadas por polimerização com dispositivo de luz led usando um molde de vidro em um gabinete estéril. Amostras de resinas cujas áreas de superfície foram calculadas de acordo com os padrões ISO (3 cm2 / ml), foram incubadas por 24 e 72 horas, a 37 o C. A viabilidade celular foi avaliada pelo ensaio de brometo de 3- [4,5-dimetiltiazol-2- il] -2,5-difeniltetrazólio (MTT) e a morte celular foi avaliada pelo ensaio de infiltração de lactato desidrogenase (LDH). Resultados: Os extratos 1: 1 dos compósitos ao final de 24 horas (exceto o composto nanocerâmico) não apresentaram efeito tóxico. Quando os resultados de viabilidade celular dos extratos 1: 1 das amostras compostas ao final de 72 horas foram analisados, estatisticamente, foram encontradas diferenças significativas em relação ao grupo controle (p < 0,05). Conclusão: Observou-se que o tipo e tamanho da carga foram eficazes na toxicidade dos compósitos, e os compósitos contendo os monômeros Bis-GMA, TEGDMA, UDMA e Bis EMA em sua matriz orgânica apresentaram viabilidade celular aceitável (70%) como especificado pela ISO. No entanto, os compósitos com monômeros PEGDMA e BPA em sua matriz orgânica apresentaram baixa viabilidade celular, que está abaixo do nível aceitável de 70%, e foram encontrados como tendo um efeito tóxico. (AU)

A comparative study of bulk-fill composites: degree of conversion, post-gel shrinkage and cytotoxicity

Abstract: Bulk-fill composites are claimed to be restorative materials used in deep preparations and effectively photoactivated in layers up to 4 mm. The aim of the present study was to evaluate the degree of conversion, post-gel volumetric shrinkage, and cytotoxicity of six bulk-fill and two conventional composites. Degree of conversion was determined by FTIR spectroscopy; post-gel volumetric shrinkage was determined using the strain gauge method; and cytotoxicity in human fibroblasts was evaluated indirectly by the MTT assay. Data were subjected to one-way ANOVA/Tukey's test (α = 0.05). All materials, including bulk-fill and conventional composites, were classified as non-toxic, with cell viability higher than 70%. Bulk-fill composites exhibited volumetric shrinkage similar to or lower (1.4 to 0.4%) than that of conventional composites (1.7-2.1%). However, only four of the bulk-fill composites were able to sustain a homogeneous conversion at the 4-mm depth. Despite their non-toxicity and shrinkage similar to that of conventional materials, not all commercial bulk-fill materials were able to maintain a conversion as high as 80% of the superficial layer, at the 4-mm depth, indicating some failure in the bulk-fill design of some commercial brands. Therefore, the use of bulk-fill materials in dental practice is advantageous, but special attention should be given to the selection and correct use of the materials.

Physicomechanical characterization and biological evaluation of bulk-fill composite resin

Abstract The aim of this study was to evaluate the cytotoxic effect, degree of conversion (% DC), Vickers hardness (VH), and surface morphology of composite resins. Eleven resins, nine bulk-fill resins, and two conventional resins were evaluated. Each material was sampled to evaluate DC (using FTIR), VH, cytotoxicity (using MTT and Neutral Red - NR test), surface morphology (using SEM and AFM), and organic filler (using EDS). All statistical tests were performed with SPSS and the level of significance was set at 0.05. MTT revealed that the materials presented low or no cytotoxic potential in relation to the control. Opus was the resin with the lowest cell viability at a 1:2 concentration at 72 h (32%) and at 7 days (43%), but that significantly increased when the NR test was applied at a 1:2 concentration after 7 days. Thickness and surface subjected to polymerization had no influence on DC, and differences were observed only between the materials. In the microhardness test, statistical differences were observed between the evaluated thicknesses. The bulk-fill resins analyzed in this study exhibited low and/or no cytotoxicity to L929 cells, except for Opus, which showed moderate cytotoxicity according to the MTT assay. When the NR test was used, results were not satisfactory for all composites, indicating the need for different methodologies to evaluate the properties of these materials. The assessed resins demonstrated acceptable physicomechanical properties.

Cytotoxicity and cytokine expression induced by silorane and methacrylate-based composite resins

ABSTRACT The successful use of composite resins in Dentistry depends on physicochemical properties, but also on the biological compatibility of resins, because of the close association between pulp and dentin. Objective The aim of this study was to evaluate cytotoxicity and cytokine production induced by light-cured or non-light-cured methacrylate-based and silorane composite resins in RAW 264.7 macrophages. Material and Methods Cells were stimulated with the extracts from light-cured or non-light-cured composite resins. After incubation for 24 h, cytotoxicity was assessed with the lactate dehydrogenase (LDH) and methyl thiazolyl tetrazolium (MTT) assays, and total protein was quantified using the Lowry method. TNF-α detection was examined with an enzyme-linked immunosorbent assay (ELISA) conducted with cell supernatants after cell stimulation for 6, 12, and 24 h. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test (α=0.05). Results KaloreTM and FiltekTM Silorane were cytotoxic with or without light curing (p<0.05) after 24 h of incubation. KaloreTM stimulated the early production of TNF-α in comparison with control (p<0.05), whereas FiltekTM Silorane did not affect TNF-α levels after 6 and 12 h (p>0.05). However, after 24 h FiltekTM Silorane inhibited the production of TNF-α (p<0.05). Conclusions KaloreTM and FiltekTM Silorane were cytotoxic regardless of light curing. The extract obtained from KaloreTM after 15 days of incubation stimulated the production of TNF-α, unlike that obtained from FiltekTM Silorane.

Long-term cytotoxic effects of contemporary root canal sealers

Objectives: The aim of the present study was to investigate the effects of root canal sealers on the cytotoxicity of 3T3 fibroblasts during a period of 5 weeks. Material and Methods: Fibroblasts (3T3, 1×105 cells per well) were incubated with elutes of fresh specimens from eight root canal sealers (AH Plus, Epiphany, Endomethasone N, EndoREZ, MTA Fillapex, Pulp Canal Sealer EWT, RoekoSeal and Sealapex) and with elutes of the same specimens for 5 succeeding weeks after immersing in simulated body fluid. The cytotoxicity of all root canal sealers was determined using the MTT assay. Data were analyzed using ANOVA and Tukey's test. Results: RoekoSeal was the only sealer that did not show any cytotoxic effects (p<0.05). All the other tested sealers exhibited severe toxicity initially (week 0). MTA Fillapex remained moderately cytotoxic after the end of experimental period. Toxicity of the other tested sealers decreased gradually over time. The evaluated root canal sealers presented varying degrees of cytotoxicity, mainly in fresh mode.Conclusions: RoekoSeal had no cytotoxic effect both freshly mixed and in the other tested time points. MTA Fillapex was associated with significantly less cell viability when compared to the other tested root canal sealers.

Effect of time of extraction on the biocompatibility of endodontic sealers with primary human fibroblasts

The aim of this work was to evaluate the effects of different times of extraction on the cytotoxicity of six representatives of different root canal sealer groups-Real Seal SE, AH Plus, GuttaFlow, Sealapex, Roth 801, and ThermaSeal Plus-with human gingival fibroblasts. The materials were prepared according to manufacturers' specifications, and were incubated in culture medium (DMEM) at 37ºC for 1, 7, 14, 21, and 28 days, with daily washing, to simulate periodontal ligament clearance. Human fibroblasts were exposed to the final extracts at 24 hours, and cell viability was determined by MTT assay, with exposure to unconditioned DMEM as a negative control. Statistical analysis comparing cytotoxicities at each exposure time was performed by ANOVA with Scheffé adjustment for multiple comparisons at a 95% confidence level. Results indicated that GuttaFlow was significantly less cytotoxic than all other sealers (p < 0.05) at 1 day of extraction. After 7 days of extraction, cell viability for GuttaFlow was significantly increased as compared with that of all groups except sealer AH Plus. At day 14, cytotoxicity of Sealapex was significantly higher than that of all other sealers (p < 0.05). At days 21 and 28, there were no significant differences in cytotoxicity among sealer groups. All materials presented some level of cytotoxicity to fibroblasts, while GuttaFlow was the least cytotoxic sealer tested. However, the cytotoxicity of all materials seemed to decrease similarly in a time-dependent manner.

Novel experimental cements for use on the dentin-pulp complex

This aim of this study was to evaluate the physicochemical and biological properties of novel experimental cements (Hybrid, Paste and Resin) based on synergistic combinations of existing materials, including pH, diametral tensile strength (DTS) and cytotoxicity comparing them with mineral trioxide aggregate (MTA - Angelus®) and a glass ionomer cement (GIC) developed at our laboratory. For the physicochemical and biological tests, specimens with standard dimensions were produced. pH measurements were performed with digital pH meter at the following time intervals: 3, 24, 48 and 72 h. For the DTS test, cylindrical specimens were subjected to compressive load until fracture. The MTT assay was performed for cytotoxicity evaluation. Data were analyzed by ANOVA and Tukey's test (α=0.05). Paste group showed pH values similar to MTA, and Hybrid group presented pH values similar to GIC (p>0.05). The tested materials showed pH values ranging from alkaline to near neutrality at the evaluated times. MTA and GIC showed similar DTS values. The lowest and highest DTS values were seen in the Paste and Resin groups, respectively (p<0.05). Cell viability for MTA and experimental Hybrid, Paste and Resin groups was 49%, 93%, 90% and 86%, respectively, when compared with the control group. The photo-cured experimental resin cement showed similar or superior performance compared with the current commercial or other tested experimental materials.

O objetivo deste estudo foi avaliar propriedades físico-químicas e biológicas de novos cimentos experimentais (Híbrido, Pasta e Resinoso) baseado na combinação sinérgica de materiais existentes, incluindo pH, resistência à tração diametral (RTD) e citotoxidade, comparando-os ao MTA (Angelus®) e a um cimento de ionômero de vidro (CIV) desenvolvido em nosso laboratório. Para a realização dos testes físico-mecânico e biológico, foram confeccionados espécimes com dimensões padrão. O teste de pH foi realizado por meio de pH-metro digital nos tempos: 3, 24, 48 e 72 h. Para o teste de RTD, espécimes cilíndricos foram submetidos a carga compressiva até sua fratura. Para avaliação da citotoxidade, utilizou-se o teste MTT. Os dados foram analisados utilizando ANOVA e teste de Tukey (α=0,05). O grupo Pasta apresentou valores de pH semelhantes ao MTA, assim como o grupo Híbrido seguiu os parâmetros do CIV (p>0,05). Todos os materiais apresentaram valores de pH alcalinos ou próximosà neutralidade nos tempos avaliados. MTA e CIV apresentaram valores de RTD similares. Os menores e maiores valores observados foram do grupo Pasta e Resinoso, respectivamente (p<0,05). A viabilidade celular para os grupos MTA, Híbrido, Pasta, Resinoso, quando comparados ao grupo controle foi de: 49, 93, 90 e 86%, respectivamente. O cimento experimental Resinoso apresentou desempenho similar ou superior aos materiais comerciais e experimentais avaliados.

FiltekTM Silorane and FiltekTM Supreme XT resins: tissue reaction after subcutaneous implantation in isogenic mice

The aim of this study was to evaluate the tissue compatibility of a silorane-based resin system (FiltekTM Silorane) and a methacrylate-based nanoparticle resin (FiltekTM Supreme XT) after implantation in the subcutaneous connective tissue of isogenic mice. One hundred and thirty five male isogenic BALB/c mice were randomly assigned to 12 experimental and 3 control groups, according to the implanted material and the experimental period of 7, 21 and 63 days. At the end of each period, the animals were killed and the tubes with the surrounding tissues were removed and processed for microscopic analysis. Samples were subjected to a descriptive and a semi-quantitative analyses using a 4-point scoring system (0-3) to evaluate the collagen fiber formation and inflammatory infiltrate. Data were statistically analyzed using the Kruskal Wallis test (?=0.05). The results showed that there was no significant difference between the experimental and control groups considering the three evaluation periods (p>0.05). The silorane-based and the methacrylate-based nanoparticle resins presented similar tissue response to that of the empty tube (control group) after subcutaneous implantation in isogenic mice.

O objetivo do presente estudo foi avaliar a compatibilidade tecidual de um sistema resinoso à base de silorane (FiltekTM Silorane) e de uma resina nanoparticulada à base de metacrilato (FiltekTM Supreme XT), após implantação no tecido conjuntivo subcutâneo de camundongos isogênicos. Um total de 135 camundongos isogênicos BALB/c machos foram randomicamente divididos em 12 grupos experimentais e em 3 grupos controles, de acordo com o material implantado e com o período experimental (7, 21 e 63 dias). Ao final de cada período, os animais foram mortos, sendo os tubos removidos com o tecido circundante e processados para análise microscópica. As lâminas foram submetidas a análise descritiva e análise semi-quantitativa empregando um sistema de escores de 4 pontos (0-3), a fim de avaliar a formação de fibras colágenas e o infiltrado inflamatório. Os dados obtidos foram submetidos à análise estatística por meio do teste de Kruskal Wallis (?=0,05). Os resultados mostraram que não houve diferença estatisticamente significante entre os grupos experimentais e controles, considerando os três períodos de avaliação (p>0,05). As resinas à base de silorane e à base de metacrilato apresentaram resposta tecidual semelhante à do tubo vazio (controle), após implantação no tecido conjuntivo de camundongos isogênicos.

Effects of light-curing time on the cytotoxicity of a restorative composite resin on odontoblast-like cells

This in vitro study evaluated the cytotoxicity of an experimental restorative composite resin subjected to different light-curing regimens. METHODS: Forty round-shaped specimens were prepared and randomly assigned to four experimental groups (n=10), as follows: in Group 1, no light-curing; in Groups 2, 3 and 4, the composite resin specimens were light-cured for 20, 40 or 60 s, respectively. In Group 5, filter paper discs soaked in 5 µL PBS were used as negative controls. The resin specimens and paper discs were placed in wells of 24-well plates in which the odontoblast-like cells MDPC-23 (30,000 cells/cm²) were plated and incubated in a humidified incubator with 5 percent CO2 and 95 percent air at 37ºC for 72 h. The cytotoxicity was evaluated by the cell metabolism (MTT assay) and cell morphology (SEM). The data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests (p<0.05). RESULTS: In G1, cell metabolism decreased by 86.2 percent, indicating a severe cytotoxicity of the non-light-cured composite resin. On the other hand, cell metabolism decreased by only 13.3 percent and 13.5 percent in G2 and G3, respectively. No cytotoxic effects were observed in G4 and G5. In G1, only a few round-shaped cells with short processes on their cytoplasmic membrane were observed. In the other experimental groups as well as in control group, a number of spindle-shaped cells with long cytoplasmic processes were found. CONCLUSION: Regardless of the photoactivation time used in the present investigation, the experimental composite resin presented mild to no toxic effects to the odontoblast-like MDPC-23 cells. However, intense cytotoxic effects occurred when no light-curing was performed.

Avaliação da biocompatibilidade do compósito: biocerâmica/ácido poli (lático-co-glicólico) em fibroblastos e macrófagos e da resposta pulpar após capeamento direto / The cell biocompatibility of a bioceramic/poly (lactic-co-glycolic acid) composite and its pulp response in vivo for pulp capping application

Biocerâmicas associadas a polímeros para capeamento pulpar estão sendo investigadas pela capacidade de induzir a formação de tecido mineralizado. Esses materiais são usados na ortopedia e implantodontia com resultados clínicos eficientes. Contudo, pouco se sabe sobre seu efeito sobre a polpa dental e seus componentes celulares. O objetivo deste estudo foi avaliar a biocompatibilidade do compósito: biocerâmica de B-tricálcio fosfato/hidroxiapatita (BC) e co-polímero ácido poli (lático-co-glicólico) (PLGA) (BC/PLGA), em cultura de fibroblastos da polpa dental humana (FP5) e de macrófagos peritoneais (MP), e avaliar a resposta pulpar após capeamento direto após 30 e 60 dias...

Toxicity Testing of Restorative Dental Materials Using Brine Shrimp Larvae (Artemia salina)

This study investigated the effect of extracts of different composites, glass ionomer cement (GIC)s and compomers on the viability of brine shrimp larvae. Ethanolic extracts of four dental composites (Z-100; Solitaire 2; Filtek P60 and Synergy), a conventional GIC (Ketac-Fil), a resin-modified glass ionomer cement (Vitremer), two compomers (F2000; Dyract AP), and a flowable compomer (Dyract Flow) were prepared from each material. Following evaporation of the ethanol, the extracts were resuspended in distilled water, which was then used to test the effects on the viability of brine shrimp larvae. For the composites, the extract of Synergy was the least toxic (88 percent viability) followed by the extracts of Solitaire 2, Z100 and P60 (75 percent, 67.5 percent and 50 percent viability, respectively). One-way ANOVA revealed highly significant differences between the resin composite materials (p<0.001). Follow-up comparison between the composite groups by Tukey's pairwise multiple-comparison test (á =0.05) showed that the extract of Synergy was significantly less toxic than the extracts of all the other materials except that of Solitaire 2. The compomers showed 100 percent lethality, while the percentage of viable larvae for the extracts of Ketac-Fil, and Vitremer were 32.3 percent, and 37.0 percent, respectively. One-way ANOVA revealed highly significant differences between the groups of materials (p<0.001). Follow-up comparison between the groups by Tukey's test (á = 0.05) showed that the toxic effect of the extracts of the compomers were significantly greater than that of Ketac-Fil, and Vitremer. The differences in the toxic effects of Vitremer and Ketac-Fil were not statistically significant. In conclusion, the toxicity of composite materials varied according to their chemical composition. Compomers were the most lethal materials to brine shrimp larvae followed by GICs and then composites.

Cytotoxicity evaluation of four endodontic sealers

This study evaluated in vitro the cytotoxicity of four root canal sealers (Topseal, EndoRez, TubliSeal and Kerr Pulp Canal Sealer E.W.T.) and their effects on reactive oxygen/nitrogen intermediate induction by mouse peritoneal macrophages. Thioglycollate-induced cells were obtained from Swiss mice by peritoneal lavage with 5 mL 10 mM phosphate-buffered saline, washed twice and resuspended (106 cells/mL) in appropriate medium for each test. Cytotoxicity was determined by the presence of hydrogen peroxide (H2O2) and nitric oxide (NO) by the peroxidase-dependent oxidation of phenol red and Griess reaction, respectively. Sealer suspensions were obtained in two different concentrations from each material: 18 mg/mL and 9 mg/mL, established according to compatibility parameters following MTT assay. Comparing the sealers, H2O2 release at concentrations of 9 mg/mL and 18 mg/mL was similar: Topseal > positive control (medium + cells + 5 mg/mL zimozan solution) > EndoRez > TubliSeal > Kerr Pulp E.W.T. > negative control (medium + cells). NO release at concentration of 9 mg/mL was: positive control (medium + cells + 10 µg/mL LPS solution) > Topseal > Kerr Pulp E.W.T. > TubliSeal = EndoRez > negative control (medium + cells); at concentration of 18 mg/mL was: positive control > Topseal > Kerr Pulp E.W.T > TubliSeal > EndoRez > negative control. Based on the results, it may be concluded that Topseal presented the highest cytotoxicity among the tested sealers, releasing higher concentrations of NO and H2O2 in macrophage culture.

Este estudo avaliou in vitro a citotoxicidade de quatro cimentos obturadores (Topseal, EndoRez, TubliSeal e Kerr Pulp Canal Sealer E.W.T) e seus efeitos na liberação de reativos intermediários do oxigênio e do nitrogênio em cultura de macrófagos peritoniais de ratos.Tioglicolato foi utlizado para se obter células peritoneias de camundongos. A cavidade peritoneal foi irrigada com 5 mL de solução salina 10 mM. As células foram lavadas duas vezes e foi feita uma suspensão (106 células/mL) em meio apropriado para cada um dos testes. A citotoxicidade dos cimentos foi determinada pela presença de peróxido de hidrogênio (H2O2) e óxido nítrico (NO) pela oxidação peroxidase-dependente do vermelho fenol e pela reação de Griess, respectivamente. Suspensões de cimento foram obtidas em duas diferentes concentrações para cada material: 18 mg/mL e 9 mg/mL, estabelecidas previamente pelo teste de viabilidade celular MTT. Comparando os cimentos, a liberação de H2O2 foi similar nas duas concentrações: Topseal > controle positivo (meio + células + Zimozan a 5mg/mL ) > EndoRez > TubliSeal > Kerr Pulp E.W.T. > controle negativo (meio + células). A liberação de NO na concentração de 9 mg/mL foi: de 9 mg/mL foi: controle positivo (meio + células + solução de LPS a 10 »g/mL) > Topseal > Kerr Pulp E.W.T. > TubliSeal = EndoRez > controle negativo (meio + células); e na concentração de 18 mg/mL; e na concentração de 18 mg/mL: controle positivo > Topseal > Kerr Pulp E.W.T > TubliSeal > EndoRez > controle negativo. Baseado nos resultados, pode-se concluir que o Topseal apresentou a maior citotoxicidade dentre os cimentos avaliados, liberando as mais altas concentrações de NO e H2O2 em cultura de macrófagos.

Cytotoxic effects of cyanoacrylates used as retrograde filling materials: an in vitro analysis

Cyanoacrylate has been used in medicine and dentistry for many years. It has been used as a postextraction dressing and retrograde filling material in endodontic surgery. The aim of this study was to evaluate the cytotoxic effects of Histoacryl and other two homologue ethyl cyanoacrylates, Super Bonder and Ultrabond, on cultured fibroblasts, using the Trypan blue dye exclusion assay. The cyanoacrylates were applied to round glass coverslips, which were placed in contact with NIH 3T3 cells. After 0, 6, 12 and 24 h (short-term assay; viability) and 1, 3, 5 and 7 days (long-term assay; survival), the cells were examined under phase light microscopy and counted. The data were compared by the Kruskal-Wallis test. In the short-term experiments, only the cultures of the Ultrabond group (GIV) presented significant smaller percentages of cell viability than the cultures of the other groups (GI: control; GII: Super Bonder; GIII: Histoacryl). Although the cultures of the Super Bonder group (GII) presented smaller percentages of cell viability than cultures of the other groups (GI, GIII, GIV) at the long-term assay, this group was the only experimental group presenting a continuous and progressive cell growth. Our results have shown an in vitro biocompatibility of Histoacryl and ethyl cyanoacrylate homologues. These cyanoacrylates could therefore be of importance for endodontic purposes

Avaliaçäo histológica preliminar da biocompatibilidade do cimento ionomérico modificado fotopolimerizável - variglass VLC e de um cimento a base de CA(OH) - Dycal, quanto implantados em tecido subcutâneo de ratos / Preliminary histological evaluation of biocompatibility of resin modified glass ionomer - variglass VLC and calcium hydroxide cement - Dycal, when implanted into rat's connective tissue

Os compômeros ou ionocompósitos säo materiais restauradores híbridos, derivados dos cimentos de ionômero de vidro convencionais com pequenas adiçöes de resinas compostas fotoativada, exibindo propriedades intermediárias aos dois materiais, com algumas características superiores aos cimentos ionoméricos. O objetivo do trabalho foi avaliar de forma comparativa a biocompatibilidade do compômeros Variglass VLC e do cimento de hidróxido de cálcio - Dycal. Para isto ambos materiais foram implantados no tecido conjuntivo subcutâneo de ratos, onde permaneceram pelos períodos de 7, 15, 30 e 60 dias. Variglass VLC provocou no primeiro período de células inflamatórias ao 7 dias, sendo que a área reacional atingiu amplitude avaliaçäo, moderada - intensa reaçäo inflamatória, onde a área reacional junto à abertura tubular tinha amplitude média de 3,822 mm, decrescendo com o decorrer do período para 0,506 mm. Já o grupo controle (Dycal) apresentou discreta quantidade média de 1,118 mm. Houve regressäo do quadro reacional com o decorrer dos períodos, sendo que aos 60 dias a amplitude média era de 0,347 mm. Conclui-se que o Variglass VLC foi mais irritante que o Dycal, porém ambos materiais apresentaram biocompatibidade aceitável