RESUMO
Biosilicate is a bioactive glass-ceramic used in medical and dental applications. This study evaluated novel reparative materials composed of pure tricalcium silicate (TCS), 30% zirconium oxide (ZrO2 ) and 10 or 20% biosilicate, in comparison with Biodentine. Setting time was evaluated based on ISO 6876 standard, radiopacity by radiographic analysis, solubility by mass loss, and pH by using a pH meter. Cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and NR assays. Alkaline phosphatase (ALP) activity and alizarin red were used to evaluate cell bioactivity. Antimicrobial activity was assessed on Enterococcus faecalis by the direct contact test. The data were submitted to analysis of variance (ANOVA)/Tukey; Bonferroni and Kruskal-Wallis, and Dunn tests (α = 0.05). The association of Biosilicate with TCS + ZrO2 had appropriate setting time, radiopacity, and solubility, alkaline pH, and antimicrobial activity. TCS and Biodentine showed higher ALP activity in 14 days than the control (serum-free medium). All cements produced mineralized nodules. In conclusion, Biosilicate + TCS ZrO2 decreased the setting time and increased the radiopacity in comparison to TCS. Biosilicate + TCS ZrO2 presented lower solubility and higher radiopacity than Biodentine. In addition, these experimental cements promoted antimicrobial activity and mineralization nodules formation, suggesting their potential for clinical use.
Assuntos
Compostos de Cálcio/química , Vidro/química , Silicatos/química , Zircônio/química , Fosfatase Alcalina , Antraquinonas , Materiais Biocompatíveis , Cimentos Ósseos , Neoplasias Ósseas/patologia , Compostos de Cálcio/farmacologia , Compostos de Cálcio/toxicidade , Linhagem Celular Tumoral , Cimentos Dentários , Enterococcus faecalis/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Teste de Materiais , Osteossarcoma/patologia , Cimento de Silicato , Silicatos/farmacologia , Silicatos/toxicidade , Solubilidade , Zircônio/farmacologia , Zircônio/toxicidadeRESUMO
AIMS: The biological reaction to wear debris is critical to the osteolysis underlying aseptic loosening of joint prosthetic implants. In an attempt to reduce aseptic loosening, ceramics have been introduced. This study was designed to evaluate, compare and correlate the expression of Toll-like receptors (TLRs), their intracellular adaptors and proinflammatory cytokines in cultured macrophages challenged with titanium or zirconia particles, as well as particle-induced osteolysis in calvaria and hyperalgesia and edema in hind paw. MAIN METHODS: TLRs and their adaptors were evaluated at the mRNA level by RT-PCR, and cytokine expression was evaluated at the mRNA and protein levels. Osteolysis and hyperalgesia and edema were evaluated in vivo, in calvaria and hind paw, respectively. KEY FINDINGS: Cultured macrophages challenged with zirconia or titanium particles expressed increased mRNA for TLRs 2, 3, 4 and 9, and their adaptors MyD88, TRIF and NF-κB and cytokines TNF-α, IL-1ß and IL-6, which were also increased at protein level. Quantitative differences are evident and, in general, zirconia particle-induced pro-inflammatory gene expression was lower than that induced by titanium particles. In in vivo experiments, exposition to titanium or zirconia particles induced osteolysis in calvaria and hyperalgesia and edema in hind paw; however those induced by zirconia particles were significantly lower. There is a strong and positive correlation between the expressions of mRNA for TLR4, NF-κB, TNF-α, IL-1ß and IL-6. SIGNIFICANCE: Collectively, our data suggest that zirconia ceramic particles are less bioactive than titanium particles.
Assuntos
Edema/induzido quimicamente , Hiperalgesia/induzido quimicamente , Inflamação/induzido quimicamente , Titânio/toxicidade , Zircônio/toxicidade , Animais , Células Cultivadas , Citocinas/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Osteólise/induzido quimicamente , RNA Mensageiro/metabolismo , Crânio/efeitos dos fármacos , Crânio/metabolismo , Receptores Toll-Like/genéticaRESUMO
INTRODUCTION: The aim of this study was to investigate the cytotoxicity of white Portland cement (PC) alone or associated with bismuth oxide (PCBi), zirconium oxide (PCZir), and calcium tungstate (PCCa) in 2 cell lineages. METHODS: Murine periodontal ligament cells (mPDL) and rat osteosarcoma cells (ROS 17/2.8) were exposed for 24 hours to specific concentrations of fresh PC and PC associations with radiopacifiers. Zinc oxide-eugenol cement and hydrogen peroxide treatment were applied as cytotoxic positive controls. Cell viability after incubation with the cements was assessed by mitochondrial dehydrogenase enzymatic assay. Cell morphology was microscopically analyzed by cresyl violet staining, and the mechanism of cell death was determined by acridine orange/ethidium bromide methodology. All data were analyzed statistically by analysis of variance and Tukey post hoc test (P < .05). The correlation among cell death by apoptosis or necrosis and pH values was established by Pearson linear coefficient. RESULTS: The mitochondrial dehydrogenase enzymatic assay only revealed significant cell death rate at high concentrations of cement elutes. PC alone was not cytotoxic, even at 100 mg/mL. Microscopic images showed that none of the PC formulations caused damage to any cell lines. Statistical analysis of apoptosis/necrosis data demonstrated that PC and PC plus radiopacifying agents promoted significant necrosis cell death only at 100 mg/mL. CONCLUSIONS: The mPDL cells were more sensitive than ROS17/2.8. The results showed that PC associated with bismuth oxide, zirconium oxide, or calcium tungstate is not cytotoxic to mPDL or ROS17/2.8. Zirconium oxide and calcium tungstate might be good alternatives as radiopacifying agents.
Assuntos
Morte Celular/efeitos dos fármacos , Meios de Contraste/toxicidade , Cimentos Dentários/toxicidade , Materiais Restauradores do Canal Radicular/toxicidade , Análise de Variância , Animais , Bismuto/química , Bismuto/toxicidade , Compostos de Cálcio/química , Compostos de Cálcio/toxicidade , Linhagem Celular , Meios de Contraste/química , Cimentos Dentários/química , Relação Dose-Resposta a Droga , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Camundongos , Osteócitos/citologia , Osteócitos/efeitos dos fármacos , Ligamento Periodontal/citologia , Ratos , Materiais Restauradores do Canal Radicular/química , Estatísticas não Paramétricas , Compostos de Tungstênio/química , Compostos de Tungstênio/toxicidade , Zircônio/química , Zircônio/toxicidadeRESUMO
AIM: To evaluate whether several radiopacifiers are able to induce genetic damage in a laboratory cell culture study. METHODOLOGY: Murine fibroblasts were exposed to barium sulphate, bismuth oxide or zirconium oxide, at final concentrations ranging from 10 to 1000 microg mL(-1) for 1 h at 37 degrees C. The negative control group was treated with a vehicle control [phosphate buffered solution (PBS)] for 1 h at 37 degrees C and the positive control group was treated with hydrogen peroxide (at 10 microM) for 5 min on ice. Genotoxicity data were assessed by the single-cell gel (comet) assay. RESULTS: All the tested compounds did not induce DNA breakage as depicted by the mean tail moment in all the concentrations analysed. CONCLUSION: Exposure to the tested radiopacifiers may not be a factor that increases the level of DNA lesions in mammalian cells as detected by a single-cell gel (comet) assay.
Assuntos
Células 3T3/efeitos dos fármacos , Meios de Contraste/toxicidade , Dano ao DNA , Animais , Sulfato de Bário/toxicidade , Bismuto/toxicidade , Ensaio Cometa , Camundongos , Zircônio/toxicidadeRESUMO
OBJECTIVES: The objective was to evaluate the response of human pulps capped with different components from a total-etch three-step adhesive system. METHODS: Direct pulp capping was performed in 25 caries-free human premolars scheduled for extraction due to orthodontic treatment. The teeth were randomly divided in five groups, and capped with the following materials: Group 1-acid+primer+adhesive were used as recommended; Group 2-only primer was applied; Group 3-only bonding resin (light-cured for 10s); Group 4-only composite resin (light-cured for 40s); Group 5-calcium hydroxide. After capping, all teeth were restored with ScotchBond Multi Purpose Plus and Z-100 was placed incrementally. After 60 days, the teeth were extracted and processed for light microscopic examination (H/E) according to a histological score system. These were subjected to non-parametric tests (alpha<0.05). RESULTS: Overall, the histological features showed that groups 1-4 were quite similar and inferior to group 5. In groups 1-4 the pulp response varied from acute inflammatory cell infiltrate with varying degrees to necrosis. The groups 3 and 4 showed a trend towards better pulp response, since a normal connective tissue could be observed in more than half of the sample. All teeth from group 5 showed normal connective tissue below an amorphous dentin bridge. SIGNIFICANCE: Adhesive components (primer or adhesive) as well as a composite should be avoided for pulp capping. Ca(OH)(2) should be the first choice for pulp capping.
Assuntos
Adesivos/toxicidade , Capeamento da Polpa Dentária/efeitos adversos , Polpa Dentária/efeitos dos fármacos , Cimentos de Resina/toxicidade , Condicionamento Ácido do Dente/efeitos adversos , Adolescente , Adulto , Hidróxido de Cálcio/uso terapêutico , Resinas Compostas/toxicidade , Necrose da Polpa Dentária/induzido quimicamente , Humanos , Teste de Materiais , Hemorragia Bucal/induzido quimicamente , Pulpite/induzido quimicamente , Dióxido de Silício/toxicidade , Zircônio/toxicidadeRESUMO
AIM: To evaluate the biological properties of a variety of materials that could be used in apical surgery. METHODOLOGY: The intraosseous implant technique recommended by the FDI (1980) and ADA (1982) was used to test the following materials: zinc oxide-eugenol (ZOE), mineral trioxide aggregate (MTA), and Z-100 light-cured composite resin. Thirty guinea-pigs, 10 for each material, divided into experimental periods of 4 and 12 weeks, received one implant on each side of the lower jaw symphysis. The connective tissue response alongside the lateral wall outside the cup served as a negative control for the technique. At the end of the observation periods, the animals were killed and the specimens prepared for routine histological examination to evaluate their biocompatibility. RESULTS: The reaction of the tissue to the materials diminished with time. The ZOE cement was highly toxic during the 4-week experimental period, but this profile changed significantly after 12 weeks, when it showed biocompatible characteristics. MTA and Z-100 showed biocompatibility in this test model at both time periods. CONCLUSIONS: MTA and Z-100 composite were biocompatible at 4 and 12 weeks in this experimental model.
Assuntos
Materiais Restauradores do Canal Radicular/toxicidade , Compostos de Alumínio/toxicidade , Animais , Apicectomia , Compostos de Cálcio/toxicidade , Resinas Compostas/toxicidade , Combinação de Medicamentos , Cobaias , Implantes Experimentais , Óxidos/toxicidade , Obturação Retrógrada , Silicatos/toxicidade , Dióxido de Silício/toxicidade , Cimento de Óxido de Zinco e Eugenol/toxicidade , Zircônio/toxicidadeRESUMO
This in vitro study evaluated the cytotoxic effects of a restorative resin composite applied to an immortalized odontoblast-cell line (MDPC-23). Seventy-two round resin discs (2-mm thick and 4 mm in diameter) were light-cured for 20 or 40 seconds and rinsed, or not, with PBS and culture medium. The resin discs were divided into four experimental groups: Group 1: Z-100/20 seconds; Group 2: Z-100/20 seconds/rinsed; Group 3: Z-100/40 seconds; Group 4: Z-100/40 seconds/rinsed. Circular filter paper was used as a control material (Group 5). The round resin discs and filter papers were placed in the bottom of wells of four 24-well dishes (18 wells for each experimental and control group). MDPC-23 cells (30,000 cells/cm2) were plated in the wells and allowed to incubate for 72 hours. The zone of inhibition around the resin discs was measured under inverted light microscopy; the MTT assay was carried out for mitochondrial respiration and cell morphology was measured under SEM. The scores obtained from inhibition zone and MTT assay were analyzed with the Kruskal-Wallis followed by Dunnett tests. In Groups 1, 2, 3 and 4, the thickness of the inhibition zone was 1,593 +/- 12.82 microm, 403 +/- 15.49 microm, 1,516 +/- 9.81 microm and 313 +/- 13.56 microm, respectively. There was statistically significant difference among the experimental and control groups at the 0.05 level of significance. The MTT assay demonstrated that the resin discs of the experimental groups 1, 2, 3 and 4 reduced the cell metabolism by 83%, 40.1%, 75.5% and 24.5%. Only between the Groups 2 and 4 was there no statistically significant difference for mitochondrial respiration. Close to the resin discs, the MDPC-23 cells exhibited rounded shapes, with only a few cellular processes keeping the cells attached to the substrate or, even disruption of plasma membrane. Adjacent to the inhibition zone, the cultured cells exhibited multiple fine cellular processes on the cytoplasmic membrane organized in epithelioid nodules, similar to the morphology observed to the control group. Based on the results, the authors may conclude that the Z-100 resin composite light cured for 20 seconds was more cytopathic to MDPC-23 cells than Z-100 light cured for 40 seconds. The cytotoxic effects of the resin discs decreased after rinsing them with PBS and culture medium. This was confirmed by MTT assay and upon evaluation of the inhibition zone, which was narrower following rinsing of the resin discs.
Assuntos
Resinas Compostas/toxicidade , Odontoblastos/efeitos dos fármacos , Dióxido de Silício/toxicidade , Zircônio/toxicidade , Linhagem Celular Transformada , Respiração Celular/efeitos dos fármacos , Corantes/metabolismo , Resinas Compostas/efeitos da radiação , Humanos , Luz , Mitocôndrias/efeitos dos fármacos , Dióxido de Silício/efeitos da radiação , Estatísticas não Paramétricas , Sais de Tetrazólio/metabolismo , Tiazóis/metabolismo , Fatores de Tempo , Zircônio/efeitos da radiaçãoRESUMO
Materials and devices intended for end-use applications as implants and medical devices must be evaluated to determine their biocompatibility potential in contact with physiological systems. The use of standard practices of biological testing provides a reasonable level of confidence concerning the response of a living organism to a given material or device, as well as guidance in selecting the proper procedures to be carried out for the screening of new or modified materials. This article presents results from cytotoxicity assays of cell culture, skin irritation, and acute toxicity by systemic and intracutaneous injections for powders, ceramic bodies, and extract liquids of hydroxyapatite (HA), calcia partially stabilized zirconia (ZO), and two types of zirconia-hydroxyapatite composites (Z4H6 and Z6H4) with potential for future use as orthopedic and dental implants. They indicate that these materials present potential for this type of application because they meet the requirements of the standard practices recommended for evaluating the biological reactivity of ATCC cell cultures (CCL1 NCTC clone 929 of mouse connective tissue and CCL 81 of monkey connective tissue) and animals (rabbit and mouse) with direct or indirect patient contact, or by the injection of specific extracts prepared from the material under test. In addition, studies involving short-term intramuscular and long-term implantation assays to estimate the reaction of living tissue to the composites studied, and investigations on long-term effects that these materials can cause on the cellular metabolism, are already in progress.