RESUMO
The aim of this study was to evaluate the influence of different calcium phosphates (CaPs) on the physical, biological, and remineralizing properties of experimental resin-based sealants (RBSs). Triethylene-glycol dimethacrylate (90wt%) and bisphenol A-glycidyl methacrylate (10wt%) were used to produce resin-based sealants. Hydroxyapatite (SHAp), α-tricalcium phosphate (Sα-TCP) and octacalcium phosphate (SOCP) were added to the sealants in a 10wt% concentration. One group without CaPs was used as the control group (SCG). The degree of conversion (DC) was assessed with Fourier-transformed infrared spectroscopy, whereas cytotoxicity was tested with the HaCaT keratinocyte cell line. The ultimate tensile strength (UTS) was used to assess the mechanical strength of the experimental RBSs. Sealed enamel was used for colorimetric assay. Mineral deposition was assessed with Raman spectroscopy after 7, 14, and 28 days of sample immersion in artificial saliva. Scanning electron microscopy was used to analyze the surface morphology after 28 days of immersion. The addition of 10wt% of fillers significantly reduced the DC of sealants. SOCP groups showed reduced cell viability. Higher UTS was found for Sα-TCP and SHAp. The color analysis showed that SGC and demineralized teeth presented higher mismatches with the sound tissue. Mineral deposition was observed for SHAp and Sα-TCP after 7 days, with increased phosphate content and mineral deposits for SHAp after 28 days. RBS with the addition of 10% HAp promoted increased mineralization in vitro after 28 days, and did not affect cell viability, DC, mechanical properties, or RBS color in the enamel.
Assuntos
Fosfatos de Cálcio/química , Durapatita/química , Minerais/química , Selantes de Fossas e Fissuras/química , Resinas Sintéticas/química , Animais , Fosfatos de Cálcio/toxicidade , Bovinos , Linhagem Celular , Colorimetria , Esmalte Dentário/química , Esmalte Dentário/efeitos dos fármacos , Durapatita/toxicidade , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Selantes de Fossas e Fissuras/toxicidade , Valores de Referência , Reprodutibilidade dos Testes , Resinas Sintéticas/toxicidade , Saliva Artificial/química , Análise Espectral Raman , Propriedades de Superfície , Resistência à Tração , Fatores de TempoRESUMO
INTRODUCTION: Ceramic brackets are chemically inert in the oral cavity, whereas polycarbonate and polyoxymethylene brackets can degrade and release bisphenol-A and formaldehyde, respectively. More reliable tests are needed to assess the potential toxicity of these materials. In addition to traditional cytotoxicity tests, the study of nitric oxide (NO) cellular production stimulated by a specific material has been shown to be a reliable tool for evaluating cytotoxic potential. The purpose of this study was to assess, with esthetic brackets, cellular viability by 3,(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide assay (Sigma, St. Louis, Mo) in the macrophage cell line J774 stimulated with interferon gamma. Interferon gamma is a key cytokine in the activation of macrophages, plays an important role in immunologic processes, and also quantifies NO production by these macrophages. METHODS: Well plates were seeded with 2 x 104 J774 cells per well, in a volume of 100 microL, resuspended in Roswell Park Memorial Institute Supplemented Medium 1640. The macrophage cell line J774 was stimulated with interferon gamma. Ceramic, polycarbonate, and polyoxymethylene brackets were added and kept in the culture for 24, 48, or 72 hours in 5% carbon dioxide at 37 degrees C; the control samples did not include brackets. At the end of each incubation period, the supernatant was collected for posterior NO quantification, and the cells were evaluated for cytotoxicity. RESULTS: Cellular viability in all groups was higher at 72 hours than at 24 hours. The final means in the bracket groups did not show significant differences compared with the control group. NO production was significantly greater in all groups at the final time than at the initial time. However, the brackets with the interferon gamma stimulation did not result in greater NO production than did the cells in the control group.
Assuntos
Cerâmica/toxicidade , Materiais Dentários/toxicidade , Interferon gama/farmacologia , Macrófagos/efeitos dos fármacos , Óxido Nítrico/biossíntese , Braquetes Ortodônticos , Cimento de Policarboxilato/toxicidade , Resinas Sintéticas/toxicidade , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Corantes , Ativação de Macrófagos/efeitos dos fármacos , Macrófagos/citologia , Teste de Materiais , Camundongos , Óxido Nítrico/análise , Temperatura , Sais de Tetrazólio , Tiazóis , Fatores de TempoRESUMO
INTRODUCTION: Studies show that ceramic brackets are chemically inert in the oral cavity, whereas polycarbonate and polyoxymethylene brackets can degrade, releasing bisphenol-A and formaldehyde, respectively. In addition to the traditional cytotoxicity tests, the study of nitric oxide cellular production stimulated by a specific material has been shown to be a reliable tool for evaluating its cytotoxic potential. METHODS: We aimed to assess cellular viability by MTT (Sigma, St. Louis, Mo): 3,(4,5-dimethylthiazol-2-yl)-2,5diphenyl tetrazolium bromide assay in a murine macrophage cell line J774 with esthetic brackets and quantify nitric oxide production by these macrophages. Cell cultures were evaluated at 3 times: 24, 48, and 72 hours. RESULTS: Cellular viability in all groups was higher at 72 hours compared with 24 hours. This increase was significant in the control and ceramic brackets groups. Final means in the bracket groups showed no significant differences compared with the control group. Nitric oxide production was significantly greater in all groups at final time. There was no significant difference between the final means of the bracket groups and the control group, although polyoxymethylene brackets showed significantly greater means at 24 and 48 hours. CONCLUSIONS: Final means in the bracket groups showed no significant differences compared with the control group.
Assuntos
Materiais Dentários/toxicidade , Macrófagos/metabolismo , Óxido Nítrico/metabolismo , Braquetes Ortodônticos , Animais , Contagem de Células/métodos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Colorimetria/métodos , Materiais Dentários/química , Porcelana Dentária/química , Porcelana Dentária/toxicidade , Formazans , Macrófagos/efeitos dos fármacos , Teste de Materiais/métodos , Camundongos , Cimento de Policarboxilato/química , Cimento de Policarboxilato/toxicidade , Resinas Sintéticas/química , Resinas Sintéticas/toxicidade , Estatísticas não Paramétricas , Sais de TetrazólioRESUMO
The present in vivo study investigated the genotoxicity of four dental resin monomers: triethyleneglycoldimethacrylate (TEGDMA), hydroxyethylmethacrylate (HEMA), urethanedimethacrylate (UDMA) and bisphenol A-glycidylmethacrylate (BisGMA). The Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster was applied to analyse their genotoxicity expressed as homologous mitotic recombination, point and chromosomal mutation. SMART detects the loss of heterozygosity of marker genes expressed phenotypically on the fly's wings. This fruit fly has an extensive genetic homology to mammalians, which makes it a suitable model organism for genotoxic investigations. The present findings provide evidence that the mechanistic basis underlying the genotoxicity of UDMA and TEGDMA is related to homologous recombination and gene/chromosomal mutation. A genotoxic pattern can correspondingly be discerned for both UDMA and TEGDMA: their genotoxicity is attributed respectively to 49% and 44% of mitotic recombination, as well as 51% and 56% of mutational events, including point and chromosomal alterations. The monomer UDMA is 1.6 times more active than TEGDMA to induce mutant clones per treatment unit. BisGMA and HEMA had no statistically significant effect on total spot frequencies - suggesting no genotoxic action in the SMART assay. The clinical significance of these observations has to be interpreted for data obtained in other bioassays.
Assuntos
Dano ao DNA/efeitos dos fármacos , Mutagênicos/toxicidade , Resinas Sintéticas/toxicidade , Animais , Drosophila melanogaster/genética , Mitose/efeitos dos fármacos , Testes de Mutagenicidade , Mutação/efeitos dos fármacos , Mutação Puntual/efeitos dos fármacosRESUMO
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 (p<0.05). Ten-fold dilutions of L&C, Fill Canal and AH Plus killed 24, 35 and 61% of THP-1 cells (p<0.05), respectively. Dilutions lesser than 1% caused minimal cell death as compared to the control groups (p>0.05), except for L&C 1% extract. CONCLUSIONS: The results revealed that the L&C paste crude extract was less cytotoxic to THP-1 cells than AH Plus or Fill Canal crude extracts.
Assuntos
Hidróxido de Cálcio/toxicidade , Materiais Restauradores do Canal Radicular/toxicidade , Sulfato de Bário/toxicidade , Bismuto/toxicidade , Boratos/toxicidade , Contagem de Células , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Corantes , Combinação de Medicamentos , Resinas Epóxi/toxicidade , Eugenol/toxicidade , Humanos , Teste de Materiais , Monócitos/efeitos dos fármacos , Resinas Sintéticas/toxicidade , Azul Tripano , Óxido de Zinco/toxicidade , Cimento de Óxido de Zinco e Eugenol/toxicidadeRESUMO
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 percent, 1 percent, 0.1 percent, 0.01 percent, 0.001 percent and 0.0001 percent 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 percent significance level. RESULTS: Crude extract of AH Plus and Fill Canal killed approximately 90 percent of THP-1 cells versus 36 percent of THP-1 cells killed by L&C crude extract (p<0.05). Ten-fold dilutions of L&C, Fill Canal and AH Plus killed 24, 35 and 61 percent of THP-1 cells (p<0.05), respectively. Dilutions lesser than 1 percent caused minimal cell death as compared to the control groups (p>0.05), except for L&C 1 percent extract. CONCLUSIONS: The results revealed that the L&C paste crude extract was less cytotoxic to THP-1 cells than AH Plus or Fill Canal crude extracts.
Assuntos
Humanos , Hidróxido de Cálcio/toxicidade , Materiais Restauradores do Canal Radicular/toxicidade , Sulfato de Bário/toxicidade , Bismuto/toxicidade , Boratos/toxicidade , Contagem de Células , Linhagem Celular Tumoral , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Corantes , Combinação de Medicamentos , Resinas Epóxi/toxicidade , Eugenol/toxicidade , Teste de Materiais , Monócitos/efeitos dos fármacos , Resinas Sintéticas/toxicidade , Azul Tripano , Cimento de Óxido de Zinco e Eugenol/toxicidade , Óxido de Zinco/toxicidadeRESUMO
OBJECTIVE: The aim of this in vitro study was to evaluate the cytotoxicity of resin-modified glass-ionomer lining cements submitted to different curing regimes and applied to an immortalized odontoblast-cell line (MDPC-23). METHODS: Forty round-shaped specimens of each experimental material (Fuji Lining LC and Vitrebond) were prepared. They were light-cured for the manufacturers' recommended time (MRT = 30 s), under-cured (0.5 MRT = 15 s), over-cured (1.5 MRT = 45 s) or allowed to dark cure (0 MRT). Sterilized filter papers soaked with either 5 microL of PBS or HEMA were used as negative and positive control, respectively. After placing the specimens individually in wells of 24-well dishes, odontoblast-like cells MDPC-23 (30,000 cells/cm2) were plated in each well and incubated for 72 h in a humidified incubator at 37 degrees C with 5% CO2 and 95% air. The cytotoxicity was evaluated by the cell metabolism (MTT assay) and cell morphology (SEM). RESULTS: Fuji Lining LC was less cytotoxic than Vitrebond (p < 0.05) in all the experimental conditions. However, the cytotoxicity of Fuji Lining LC was noticeably increased in the absence of light-curing while the same was not observed for Vitrebond. The length of light-curing (15, 30 or 45 s) did not influence the toxicity of both lining materials when they were applied on the odontoblast-cell line MDPC-23. SIGNIFICANCE: The light-activation plays an important role in reducing the cytotoxicity of Fuji Lining LC. Following the manufacturer' recommendation regarding the light-curing regime may prevent toxic effect to the pulp cells.
Assuntos
Adesivos Dentinários/toxicidade , Cimentos de Ionômeros de Vidro/toxicidade , Odontoblastos/efeitos dos fármacos , Resinas Sintéticas/toxicidade , Animais , Linhagem Celular Transformada , Forma Celular/efeitos dos fármacos , Corantes/metabolismo , Forramento da Cavidade Dentária , Adesivos Dentinários/efeitos da radiação , Cimentos de Ionômeros de Vidro/química , Cimentos de Ionômeros de Vidro/efeitos da radiação , Luz , Metacrilatos/toxicidade , Camundongos , Microscopia Eletrônica de Varredura , Transição de Fase , Resinas Sintéticas/efeitos da radiação , Sais de Tetrazólio/metabolismoRESUMO
OBJECTIVES: To evaluate the effects of current resin-modified glass-ionomer cements (RMGICs) applied on culture of cells or implanted into subcutaneous tissue of rats. METHODS: Experiment 1 - Thirty round-shaped samples of every RMGICs: Rely X Luting Cement (RL), Vitremer (VM), and Vitrebond (VB) were placed into wells with 1.1 mL of culture medium (DMEM), and incubated for 24, 48 or 72 h. The extracts from every sample were applied on the MDPC-23 cells. Fresh DMEM was used as control group. The MTT assay was carried out for mitochondrial respiration. Experiment 2 - Fifty-four polyethylene tubes filled with the experimental materials were implanted into the dorsal subcutaneous tissue of rats. At 7, 30, and 90 days the animals were killed and the biopsies were processed for histological evaluation. RESULTS: Experiment--Both time of elution and material significantly influenced cell respiratory activity. In general, the extracts obtained at 24 h were less cytotoxic than 48 and 72 h incubation. The cytotoxic effect of VM and RL were not statistically different (p < 0.05) for the 24-hour period. VB showed the highest cytotoxic effect. Experiment 2--All RMGICs elicited at 7 days a moderate to intense inflammatory reaction which decreased over time. However, connective healing occurred for most of samples at 90-day evaluation. SIGNIFICANCE: Glass-ionomer cements may cause noticeable inflammatory response when in direct contact to connective tissue. The toxic effects of this kind of soluble material depend on the amount of components released in the aqueous environment.
Assuntos
Cimentos de Ionômeros de Vidro/toxicidade , Mitocôndrias/efeitos dos fármacos , Odontoblastos/efeitos dos fármacos , Animais , Linhagem Celular Transformada , Resinas Compostas/toxicidade , Tecido Conjuntivo/efeitos dos fármacos , Reação a Corpo Estranho , Cimentos de Ionômeros de Vidro/química , Implantes Experimentais , Camundongos , Ratos , Resinas Sintéticas/toxicidadeRESUMO
AIM: To determine the flow characteristics and subcutaneous tissue reactions to five endodontic sealers. METHODOLOGY: The materials used were Procosol, AH26, Endomethasone, Sealapex and Endion. The sealers were prepared following the manufacturers' instructions, and 0.075 mL of each material was placed on a glass surface, which was then rotated 90 degrees. The samples were stored at 37 degrees C and 95% humidity. The displacement of the sealer was recorded by measuring the difference between its original position and the position recorded at 15 and 60 min. Three samples of each material were used. Two pockets were created in the back of Wistar rats, and one silicone tube, 1 mm in diameter and 1 cm in length, was implanted in each. One was filled with one of the materials under study, and the other empty tube was implanted as a control. Fourteen days after implantation, the animals were sacrificed, and samples of the skin containing the tubes were histologically processed. Histological and histomorphometric evaluations of the tissues adjacent to the open end of the tube were carried out the volume of tissue reaction was measured histomorphometrically according to standard stereological principles. Results were statistically analysed using analysis of variance and Duncan's test. RESULTS: The highest flow values were obtained with Sealapex and AH26. Time significantly affected the flow and the material (P < (1001). Procosol and Endion produced the most severe histological reactions: these were outlined by fibrous tissue; AH26. Endomethasone and Sealapex produced reactions of smaller size and with more moderately defined limits. CONCLUSIONS: The flow did not correlate with the degree of inflammatory response. Procosol and Endion produced the most severe tissue reactions, whereas Endomethasone, Sealapex and AH26 produced only minimum reactions.