RESUMO
OBJECTIVE: To evaluate the effect of a Nisin-based dentin pretreatment solution on microtensile bond strength, antibacterial activity, and matrix metalloproteinase (MMP) activity of the adhesive interface. MATERIALS AND METHODS: 100 human molars were sectioned to expose dentin. The teeth were assigned to five groups (n = 20), according to the dentin pretreatment: 0.5%, 1.0%, or 1.5% Nisin; 0.12% chlorhexidine (positive control), and no solution (negative control), and divided into 2 subgroups: no aging, and thermomechanical aging. Specimens were etched with 37% H3PO4 for 15 s and submitted to the dentin pretreatment. Then, they were bonded with an adhesive (Adper Single Bond 2) and a resin composite for microtensile bond strength (µTBS) evaluation. Antibacterial activity against Streptococcus mutans was qualitatively examined using an agar diffusion test. Anti-MMP activity within hybrid layers was examined using in-situ zymography. Data were analyzed with two-factor ANOVA and post-hoc Tukey's test (α = 0.050). RESULTS: For µTBS, significant differences were identified for the factors "solutions" (p = 0.002), "aging" (p = 0.017), and interaction of the two factors (p = 0.002). In the absence of aging, higher µTBS was observed for the group 0.5% Nisin. In the presence of aging, all groups showed similar µTBS values. All Nisin concentrations were effective in inhibiting the growth of S. mutans. Endogenous MMP activity was more significantly inhibited using 0.5% and 1.0% Nisin (p < 0.050). CONCLUSION: 0.5% and 1.0% Nisin solutions do not adversely affect resin-dentin bond strength and exhibit a potential bactericidal effect against S. mutans. Both concentrations effectively reduce endogenous gelatinolytic activity within the hybrid layer. CLINICAL RELEVANCE: The use of 0.5% and 1.0% Nisin solutions for dentin pretreatment potentially contributes to preserving the adhesive interface, increasing the longevity of composite restorations.
Assuntos
Colagem Dentária , Nisina , Humanos , Nisina/farmacologia , Nisina/análise , Adesivos/análise , Dentina/química , Antibacterianos/farmacologia , Resinas Compostas/química , Resistência à Tração , Adesivos Dentinários/química , Cimentos de Resina/análise , Teste de MateriaisRESUMO
This research aimed to obtain the depth dependence of polymerization contraction and microporosity from irradiated dental resin cements by X-ray computed microtomography (µCT). Samples (n = 5) of commercial Relyx U200 (RU) and AllCem Core (AC) dual-cure resin cements were injected in a cylindrical Teflon sampler (25 mm3 ) and separated according to polymerization mechanism: self-cured (not irradiated) and dual-cured (irradiated from the top surface with a LED device). The cement's volume was scanned with the µCT scanning conditions kept constant. To assess the depth dependence of polymerization contraction, it was measured the displacement of the cement mass from the sample holder at 30 vertical cuts (0.1 mm distant). To probe the microporosity, the percentage of area with presence of porosity by slice was obtained. All data were statistically treated. It was observed a positive linear correlation between depth and polymerization contraction in the irradiated groups. In the other hand, the concentration of micropores decreased with increasing depth. Furthermore, the composition of the resin cement was determinant for the correlation's coefficients of these physical properties with depth. The µCT technique showed to be useful to probe physical properties of dental restorative materials that influence in the clinical outcomes, revealing that, for thin specimens, when light cured the RU cement presented mechanical behavior more favorable for clinical applications.
Assuntos
Polimerização , Cimentos de Resina/análise , Microtomografia por Raio-X , Dureza , Teste de Materiais , Porosidade , Cimentos de Resina/química , Cimentos de Resina/classificaçãoRESUMO
This research aims to probe the porosity profile and polymerization shrinkage of two different dual cure resin cements with different dentin bonding systems. The self-adhesive resin cement RelyX U200 (named RU) and the conventional Allcem Core (named AC) were analyzed by x-ray microtomography (µCT) and Scanning Electron Microscopy (SEM). Each cement was divided into two groups (n = 5): dual-cured (RUD and ACD) and self-cured (RUC and ACC). µCT demonstrated that the method of polymerization does not influence the porosity profile but the polymerization shrinkage. Fewer concentration of pores was observed for the conventional resin cement (AC), independently the method used for curing the sample. In addition, SEM showed that AC has more uniform surface and smaller particle size. The method of polymerization influenced the polymerization shrinkage, since no contraction for both RUC and ACC was observed, in contrast with results from dual-cured samples. For RUD and ACD the polymerization shrinkage was greater in the lower third of the sample and minor in the upper third. This mechanical behavior is attributed to the polymerization toward the light. µCT showed to be a reliable technique to probe porosity and contraction due to polymerization of dental cements.
Assuntos
Polimerização , Cimentos de Resina/análise , Cimentos de Resina/química , Colagem Dentária , Análise do Estresse Dentário , Adesivos Dentinários/análise , Adesivos Dentinários/química , Humanos , Teste de Materiais/métodos , Microscopia Eletrônica de Varredura/métodos , Porosidade , Resistência à Tração , Microtomografia por Raio-X/métodosRESUMO
The aim of this double-blind randomized study was to evaluate the biocompatibility of resin-modified glass ionomer cements (RMGIC) by means of morphological and immunohistochemical analyses. RMGICs were selected and divided into four groups: Group CK (Crosslink Orthodontic Band Cement); Group RS (Resilience Light Cure Band Cement) Group RMO (RMO Band Cement), Group TP (Transbond Plus Light Cure Band), and Group C (Control-polyethylene). The materials were implanted in rat subcutaneous tissues, randomly selected for this study. After time intervals of 7, 15, and 30 days the tissues were submitted to morphological analysis. In immunohistochemical analysis, the immuno-marking of antibody CD68 was evaluated. The results obtained were statistically analyzed by the Kruskal-Wallis and Dunn tests (p < .05). In the morphological analysis after 7 days, Groups RS, RMO and TP showed more intense inflammatory infiltrate (p = .004) and only Group RMO presented greater intensity of multinucleated giant cells (p = .027). In the immunohistochemical analysis, Groups RMO and RS were observed to present a larger quantity of CD68+ (p = .004) in the time interval of 7 days and only Group RMO presented statistically significant difference for this parameter after 15 days (p = .026). In the time interval of 30 days, Group RMO presented the largest quantity of multinucleated giant cells (p < .004). The RMGICS Crosslink and Transbond Plus provided significantly better tissue biocompatibility than the Resilience and RMO Cements.
Assuntos
Materiais Biocompatíveis/química , Bis-Fenol A-Glicidil Metacrilato/análise , Cimentos Dentários/análise , Cimentos de Resina/química , Animais , Antígenos CD , Antígenos de Diferenciação Mielomonocítica , Materiais Biocompatíveis/análise , Bis-Fenol A-Glicidil Metacrilato/química , Colagem Dentária , Cimentos Dentários/química , Método Duplo-Cego , Células Gigantes/imunologia , Células Gigantes/ultraestrutura , Humanos , Imuno-Histoquímica , Inflamação , Macrófagos/imunologia , Macrófagos/fisiologia , Masculino , Teste de Materiais/métodos , Distribuição Aleatória , Ratos , Ratos Wistar , Cimentos de Resina/análise , Tela Subcutânea/anatomia & histologia , Tela Subcutânea/imunologia , Tela Subcutânea/fisiologiaRESUMO
Objetivo: O objetivo desse estudo foi avaliar e comparar as propriedades mecânicas dos cimentos resinosos duais convencionais e autoadesivos em macro e nanoescala. Métodos: Foram confeccionados 15 espécimes de cada marca de cimentos resinosos, AllCem (FGM), RelyX ARC (3M/ESPE) e RelyX U200 (3M/ESPE), para cada teste realizado (flexão de três pontos, compressão e nanoindentação) de acordo com as instruções dos fabricantes. Os espécimes foram fotoativados com aparelho Optilux Demetron (Kerr) por 40 segundos e armazenados em frascos escuros a 37ºC por 24 horas. Foram obtidos os resultados de resistência flexural, resistência à compressão, dureza e de módulo de Young para os diferentes testes mecânicos. Os dados foram avaliados pelos testes ANOVA, múltiplas comparações de Tukey HSD para análise dos valores de resistência, dureza e módulo de elasticidade entre os diferentes cimentos resinosos e ANOVA dois critérios e múltiplas comparações de Games Howell para análise dos módulos de Young entre os diferentes experimentos. Resultados: Os resultados revelaram que o AllCem obteve os maiores valores de resistência flexural e compressão axial (129±22,01 MPa; 243,71±29,75, respectivamente) e o RelyX U200 os menores valores (82,35±19,83 MPa; 134,57±48,93 MPa, respectivamente). Os valores de dureza não diferiram entre os cimentos estudados. No teste de flexão os valores de módulo de Young não diferiram entre os cimentos resinosos. No teste de compressão axial o AllCem apresentou módulo de Young estatisticamente maiores que dos demais cimentos. Para nanoindentação AllCem e RelyX U200 apresentaram maiores valores de módulo de Young que RelyX ARC. Os valores de módulo de Young diferiram significativamente entre todos os experimentos (p<0.05). Conclusão: Os valores das propriedades dos cimentos resinosos podem ser influenciados pelo tipo de experimento (macro- ou nanoescala) realizado.(AU)
Aim: The aim of this study was to evaluate and compare the mechanical properties of conventional and self-adhesive dual resin cements in macroscale and nanoscale. Methods: Fifteen specimens of each brand of resin cement AllCem (FGM), RelyX ARC (3M/ ESPE), and RelyX U200 (3M/ESPE) were made for each test performed in this study (three point bending, compression, and nanoindentation) according to the manufacturer's instructions. The specimens were photoactivated with Optilux Demetron (Kerr) for 40 seconds and stored in the dark at 37°C for 24 hours. Subsequently, they were submitted to flexural strength and axial compression tests at a speed of 1 mm/min, as well as to the Berkovich nanoindentation test. The results of flexural strength, compressive strength, hardness, and Young's modulus were obtained for the different mechanical tests. Data were evaluated by ANOVA tests; multiple comparisons of Tukey HSD to analyze the values of strength, hardness, and Young's modulus among the different resin cements; and ANOVA two criteria and multiple comparisons of Games Howell to analyze the Young's modulus within the different experiments. Results: The results showed that AllCem obtained the highest values of flexural strength and axial compression (129±22.01, 243.71±29.75 MPa, respectively), while RelyX U200 presented the lowest values (82.35 ± 19.83, 134.57 ± 48.93 MPa, respectively). The hardness values did not differ among the studied cements. In the flexural test, the Young's modulus values did not differ between the resin cements. In the axial compression test, AllCem presented a Young's modulus that was statistically higher than the other cements. In the nanoindentation test, AllCem and RelyX U200 presented higher values for Young's modulus than RelyX ARC. Young's modulus values differed significantly among all experiments (p <0.05). Conclusion: The values of resin cement properties can be influenced by the type of experiment (macroscale and nanoscale) performed.(AU)
Assuntos
Força Compressiva , Materiais Dentários , Testes de Dureza , Ciência dos Materiais , Cimentos de Resina/análise , Torção Mecânica , Resinas SintéticasRESUMO
Aim: To evaluate the effect of different activation protocols on the polymerization of a self-adhesive dual cured resin-based cement. Methods: Thirty disc-shaped specimens were prepared with the resin cement RelyX U200 (3M ESPE) and divided according to three protocols: immediate light-activation for 40 s, delayed light-activation (10 min after manipulation, for 40 s) or self-curing without light-activation. The specimens were desiccated, kept in water at 37 °C for 7 days and desiccated again to calculate water sorption, solubility and mass variation. Data were analyzed by Shapiro-Wilk Test and Wilcoxon tests (α=0.05). Images after the specimens' final desiccation were also made. Results: The Wilcoxon test revealed a significant difference for sorption and mass variation (p<0.05) and the highest value was observed in self-curing or chemical activation group (CA), followed by delayed light-activation (DL) and immediate light-activation (IL). Besides the water sorption parameters, there were also microvoids on the discs from the delayed and no light-activation groups. Conclusions: The light-activation immediately after manipulation is recommended for the evaluated resin cement (Au)
Assuntos
Cura Luminosa de Adesivos Dentários , Polimerização , Guias como Assunto/métodos , Cimentos de Resina/análise , Autocura de Resinas Dentárias , SolubilidadeRESUMO
There are few studies that fully characterize the effect of the filler size on the surface, optical and mechanical properties of resin composites. AIM: To determine the influence of the filler size content on surface, optical and mechanical properties before and after accelerated aging. METHODS: Seven resin composites were investigated: Filtek Supreme® (3M/ESPE), Estelite Σ Quick® (Tokuyama), Evolu-X® (Dentsply), Esthet-X HD® (Dentsply), Opallis® (FGM), Herculite XRV Ultra® (Kerr) and Filtek Z250® (3M/ESPE). Elastic modulus (EM) and flexural strength (FS) were determined by three-point bending of specimens immersed or not in absolute ethanol for seven days. Roughness (Ra) and gloss (G.U.) analyses were determined before and after ethanol storage for seven days and CIELAB color change (ΔE*) was obtained with a spectrophotometer. Results were analyzed by two-way ANOVA (general linear model) for EM and FS, with repeated measures for roughness and gloss, and one-way ANOVA for ΔE*. All comparisons were performed by Tukey's test (5%). Pearsons' correlation test was performed to determine the correlation between EM, FS, roughness, gloss, and ΔE* with the mean filler sizes. RESULTS: Mechanical properties decreased for all materials when submitted to immersion in ethanol. Increasing filler size gradually increased EM, FS and roughness values; gloss values decreased and didn't significantly affects ΔE*. Nanofiller composites presented higher gloss values than the others. CONCLUSIONS: It was possible to determine that the average filler size is a good predictor just for FS and gloss retention.
Assuntos
Cimentos de Resina/análise , Nanopartículas/análise , Resinas Compostas/análise , Propriedades de SuperfícieRESUMO
Este estudo visou avaliar a influência do tipo de ativação do agente cimentante resinoso, da espessura do material restuarador e do envelhecimento da restuaração na resistência adesiva da porcelana feldspática ao esmalte por meio de teste de microcisalhamento. Sessenta blocos cerâmicos de porcelana feldspática (VITA VM7) foram obtidos na cor A1, com as dimensões de 5x5x10mm. Eles receberam tratamento de superfície com ácido fluorídrico a 10%, silano e sistema adesivo. Paralelamente ao tratamento das porcelanas, sessenta dentes molares humanos recém-extraídos, foram aplainados na sua superfície vestibular e receberam tratamento com ácido fosfórico 37% e sistema adesivo...
Assuntos
Humanos , Masculino , Feminino , Cerâmica/análise , Cimentação/efeitos adversos , Cimentos de Resina/análise , Esmalte Dentário , Dente Molar , Porcelana Dentária/análise , Facetas Dentárias/efeitos adversos , Resistência ao CisalhamentoRESUMO
PURPOSE: The aim of this study was to evaluate the nanoleakage patterns between dental enamel and reinforced leucite ceramic, bonded with resin luting systems and a flowable composite resin. MATERIALS AND METHODS: Twelve crowns of bovine incisors were randomly divided into four groups (n = 3) according to the luting procedure: Excite/Variolink II, Clearfil SE Bond/Panavia F, Scotchbond Multi-PURPOSE Plus/RelyX ARC, and Single Bond 2/Filtek Z350 Flow. To evaluate the nanoleakage patterns, IPS Empress Esthetic disks (5 mm Ø and 1.2-mm thick) were bonded to enamel, and, after 24 h, the specimens were immersed in a 50% (w/v) solution of silver nitrate (24 h), fixed, dehydrated, and processed scanning electron microscopy (SEM). RESULTS: None nanoleakage on interface of the groups that Single Bond 2 followed by the flowable composite were used. The highest percentage of nanoleakage was shown by the Excite/Variolink II protocol. Also, in all conditions tested, none silver nitrate uptake was observed between the leucite-reinforced ceramic and the resin luting cement. CONCLUSIONS: The use of a two-step etch-and-rinse adhesive with flowable composite was able to promote an adequate seal of the bond interface at the enamel. Moreover, the conventional dual-cured resin cements associated with simplified and dual-cured adhesives tested are also indicated to bond thin ceramics to enamel, since all presented low silver nitrate uptake.
Assuntos
Silicatos de Alumínio/análise , Cerâmica/análise , Colagem Dentária/métodos , Esmalte Dentário/química , Incisivo/química , Cimentos de Resina/análise , Animais , BovinosRESUMO
O objetivo deste estudo foi correlacionar a quantidade (Artigo 1) e influência da transmissão de luz através de pinos de fibra na microdureza Knoop (KHN) e na resistência adesiva (RA) (Artigo 2) em um cimento resinoso autoadesivo de dupla polimerização. Quatro pinos de fibra de diferentes tipos e fabricantes foram utilizados para a análise quantitativa da transmissão de luz. Para KHN e RA cinco pinos também de diferentes tipos e fabricantes representaram um grupo teste...