Effect Of Polymerization Cycles On Gloss, Roughness, Hardness And Impact Strength Of Acrylic Resins

The aim of this study was to evaluate the conventional and boiled polymerization cycles on gloss, roughness, hardness and impact strength of acrylic resins. Samples were made for each Classico and QC-20 materials (n=10) in dental stone molds obtained from rectangular metallic matrices embedded in metallic flasks. The powder-liquid ratio and manipulation of the acrylic resins' were accomplished according to manufacturers' instructions and the resins were conventionally packed in metallic flasks. After polymerization by (1) conventional: 74 °C for 9 h (Classico) and (2) boiled: 20 min (QC-20) cycles, the samples were deflasked after cooling at room temperature and conventionally finished and polished. The properties were evaluated after storage in water at 37 °C for 24 h. Gloss was verified with Multi Gloss 268 meter (Konica Minolta), surface roughness was measured with Surfcorder SE 1700 rugosimeter (Kosaka), Knoop hardness number was obtained with HMV-200 microdurometer, and impact strength was measured in an Otto Wolpert-Werke device by Charpy system (40 kpcm). Data were subjected to Student's t-test (at α=0.05). The results were: Gloss: 67.7 and 62.2 for Classico and QC-20 resins, respectively; Surface roughness: 0.874 and 1.469 Ra-µm for Classico and QC-20, respectively; Knoop hardness: 27.4 and 26.9 for Classico and QC-20, respectively; and Impact strength: 37.6 and 33.6 kgf/cm2 for Classico and QC-20, respectively. No statistically significant difference (p>0.05)were found between the resins for the evaluated properties. In conclusion, conventional and boiled polymerization cycles had similar effects on gloss, roughness, hardness and impact strength of both Classico and QC-20 resins.27217618

Effect of polymerization cycles on gloss, roughness, hardness and impact strength of acrylic resins

The aim of this study was to evaluate the conventional and boiled polymerization cycles on gloss, roughness, hardness and impact strength of acrylic resins. Samples were made for each Classico and QC-20 materials (n=10) in dental stone molds obtained from rectangular metallic matrices embedded in metallic flasks. The powder-liquid ratio and manipulation of the acrylic resins' were accomplished according to manufacturers' instructions and the resins were conventionally packed in metallic flasks. After polymerization by (1) conventional: 74 °C for 9 h (Classico) and (2) boiled: 20 min (QC-20) cycles, the samples were deflasked after cooling at room temperature and conventionally finished and polished. The properties were evaluated after storage in water at 37 °C for 24 h. Gloss was verified with Multi Gloss 268 meter (Konica Minolta), surface roughness was measured with Surfcorder SE 1700 rugosimeter (Kosaka), Knoop hardness number was obtained with HMV-200 microdurometer, and impact strength was measured in an Otto Wolpert-Werke device by Charpy system (40 kpcm). Data were subjected to Student's t-test (at α=0.05). The results were: Gloss: 67.7 and 62.2 for Classico and QC-20 resins, respectively; Surface roughness: 0.874 and 1.469 Ra-µm for Classico and QC-20, respectively; Knoop hardness: 27.4 and 26.9 for Classico and QC-20, respectively; and Impact strength: 37.6 and 33.6 kgf/cm2 for Classico and QC-20, respectively. No statistically significant difference (p>0.05)were found between the resins for the evaluated properties. In conclusion, conventional and boiled polymerization cycles had similar effects on gloss, roughness, hardness and impact strength of both Classico and QC-20 resins272176180CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQSem informaçãoO propósito neste estudo foi avaliar os ciclos de polimerização convencional e por fervura sobre o brilho, rugosidade, dureza e resistência ao impacto de resinas acrílicas. Amostras foram confeccionadas para cada resina Clássico ou QC-20 (n=20) em moldes de gesso obtidos de matrizes metálicas retangulares incluídas em muflas metálicas. A proporção monômero/polímero das resinas e manipulação foram de acordo com as recomendações dos fabricantes e a massa convencionalmente incluída em muflas metálicas. Após polimerização nos ciclos (1) convencional: 74 °C por 9 horas (Clássico) e (2) fervura: 20 min (QC-20), as amostras foram demufladas após esfriadas em temperatura ambiente e convencionalmente acabadas e polidas. As propriedades foram avaliadas após armazenagem das amostras em água a 37 °C por 24 h. O brilho foi verificado com medidor Multi Gloss 268 (Konica Minolta), a rugosidade avaliada com rugosímetro Surfcorder SE 1700 (Kosaka), a dureza Knoop foi obtida com microdurômetro HMV-200 (Shimadzu) e a resistência ao impacto determinada pelo sistema Charpy (Otto Wolpert Werke). Os dados submetidos ao teste t de Student (α=0.05) mostraram que Os resultados foram: brilho: 67,7 e 62,2 para Clássico e QC-20, respectivamente; rugosidade: 0,874 e 1,469 Ra-µm para Clássico e QC-20, respectivamente; dureza: 27,4 e 26,9 para Clássico e QC-20, respectivamente; e resistência ao impacto: 37,6 e 33,6 kgf/cm2 para Clássico e QC-20, respectivamente. Não houve diference estatisticamente significante entre as resinas para as propriedades avaliadas. Conclui-se que os ciclos de polimerização convencional e por fervura promoveram similares efeitos sobre o brilho, rugosidade, dureza e resistência ao impacto para ambas as resinas Clássico e QC-2

Influence of the cavity size, photoactivation method and restorative system on marginal adaptation, knoop hardness and bond strength to root dentin

Orientadores: Mario Alexandre Coelho Sinhoreti, Simonides ConsaniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo deste estudo foi verificar a influência do volume de compósito, técnica de fotoativação e sistema restaurador sobre a adaptação marginal, dureza Knoop e resistência de união de compósitos à dentina humana radicular. Este estudo foi dividido em 2 Capítulos. O Capítulo I verificou o efeito do volume de compósito (mantendo-se o mesmo fator C) e sistema restaurador sobre a adaptação marginal, dureza Knoop e resistência de união "push-out" a dentina radicular. Foram utilizados 90 pré-molares hígidos divididos em 9 grupos (n=10), de acordo com o volume de compósito (pequena, média e grande) e sistema restaurador (Filtek Z350, Filtek Z350 Flow e Filtek LS). Os compósitos foram fotoativados por LED Ultralume 5 (Ultradent) por 20 s para Filtek Z350, Filtek Z350 Flow e 40 s para Filtek LS. A adaptação marginal foi avaliada após 24h utilizando o método do corante superficial, medindo-se a porcentagem corada em relação ao perímetro da cavidade (Caries Detector). Após a análise da adaptação marginal, as amostras foram submetidas ao ensaio de resistência de união "push-out" e de dureza Knoop na superfície do compósito. Os dados foram submetidos à análise de variância dois fatores e teste de Tukey (p=0,05). O volume de compósito não influenciou a adaptação marginal dos compósitos. Filtek LS apresentou os melhores resultados de adaptação marginal e resistência de união. Os menores valores de resistência foram apresentados pelo Filtek Z350. O volume de compósito influenciou nos valores de resistência de união e de dureza Knoop, dependendo do compósito utilizado. Os maiores valores de dureza foram apresentados pelos volumes de compósito médios. A maior dureza foi do compósito Filtek Z350, seguido por Filtek LS e Filtek Z350 flow. No Capítulo II o objetivo foi verificar a influência da modulação da intensidade da luz durante a fotoativação e volume de compósito sobre a dureza Knoop e resistência de união do compósito Filtek Z350 à dentina radicular. Foram utilizados 90 pré-molares hígidos divididos em 9 grupos (n=10), segundo o volume de compósito (pequena, média e grande) e método de fototivação (luz contínua, "pulse delay" e "soft-start"). O compósito foi fotoativado por LED Ultralume 5 (Ultradent) pelos métodos citados anteriormente. Após 24h foi realizado o ensaio de resistência de união "push-out" e de dureza Knoop na superfície do compósito. Os dados foram submetidos à análise de variância dois fatores e teste de Tukey (p=0,05). Os resultados de resistência de união mostraram que os métodos de modulação da intensidade da luz foram superiores ao contínuo, sem diferença entre eles. Cavidade média foi significativamente superior que cavidade pequena e grande para o método contínuo. O ensaio de dureza Knoop mostrou que o melhor comportamento foi apresentado pelo método pulse delay e para cavidades médias. O volume de compósito influenciou os valores de resistência de união, dureza Knoop e adaptação marginal a dentina radicular. Os maiores valores de resistência de união e adaptação marginal foram apresentados pelo compósito Filtek LS e os maiores valores de dureza pelo compósito Filtek Z350. Os métodos de modulação da intensidade de luz mostraram os melhores resultados de resistência de união, sem detrimento dos valores de dureza Knoop.Abstract: The polymerization shrinkage is one of the major drawbacks of the resin composites. The polymerization stress depends on the viscosity of the composite, rate of reaction, geometric configuration of the cavity and irradiance used during photoactivation. However, the volume of composite and low shrink monomers has been investigated. The aim of this study was to evaluate the influence of the cavity size, photoactivation technique and composite composition on marginal adaptation, Knoop hardness and push-out bond strength of composites to root dentin. This study was divided into 2 Chapters. In the Chapter 1 was to evaluate the effect of the cavity size (with similar C-factor) and restorative system on marginal adaptation, Knoop hardness and push-out bond strength to root dentin. Ninety premolars were divided into 9 groups, according to cavity size (small, middle and large) and resin composite (Filtek Z350, Filtek Z350 Flow e Filtek P90). The resin composites Filtek Z350, Filtek Z350 Flow were photoactivated with LED Ultralume 5 (Ultradent) for 20 s and Filtek P90 for 40 s. The marginal adaptation was analyzed after 24 h using Caries Detector. After that, the specimens were submitted to push-out Bond strength. The Knoop hardness examination was performed at the top surface. The data were submitted to ANOVA two-way and post hoc Tukey-s test at 95% significance level. The cavity size had no influence on marginal adaptation of the resin composites. Filtek P90 presented the best marginal adaptation, significantly better than other composites for large cavity. Filtek P90 showed the highest bond strength, significantly higher than other composites. Filtek Z350 showed the lowest bond strength results. Middle cavity presented Bond strength significantly higher than large cavity with the composite Filtek Z350. The highest Knoop hardness was showed by Filtek Z350, followed by Filtek P90 and Filtek Z350 flow. The aim of the Chapter 2 was to evaluate the influence of modulated photoacivation methods and cavity size on Knoop hardness and push-out bond strength of the composite Filtek Z350 to root dentin. Ninety premolars were divided into 9 groups, according to cavity size (small, middle and large) and photoactivation method (continuous light, pulse delay and soft-start). The composite was inserted and photoactivated with LED Ultralume 5 (Ultradent) by the methods aforementioned. The specimens were submitted to push-out Bond strength and Knoop hardness test. The data were submitted to ANOVA two-way and post hoc Tukey-s test at 95% significance level. Pulse delay showed the highest Bond strength results, significantly higher continuous light for small and large cavities. Middle cavity showed Bond strength significantly higher than small and large cavities for continuous light. Continuous light presented Knoop hardness significantly higher than soft-start for small cavity. For middle cavity, pulse delay showed Knoop hardness significantly higher than continuous light and soft-start. Pulse delay and soft-start showed Knoop hardness significantly higher than continuous light. The cavity size had influence on marginal adaptation, Knoop hardness and bond strength to root dentin. Filtek LS showed the highest bond strength and marginal adaptation results and Filtek Z350 presented the highest Knoop hardness results. The light intensity modulation methods showed the best bond strength results without decrease the Knoop hardness values.DoutoradoMateriais DentariosDoutor em Materiais Dentário

Correlation Between Bond Strength And Nanomechanical Properties Of Adhesive Interface

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The aims of this study were to evaluate the nanohardness and Young's modulus of the adhesive-dentin interface and to correlate them with the microtensile bond strength (mu TBS) after storage in water for 24 h and 6 months. Eighty human third molar teeth were bonded to composite resin with the Adper Scotchbond Multipurpose (SBMP), Adper Single Bond 2 (SB2), Clearfil SE Bond (CSE) or Clearfil S3 Bond (CS3) adhesive systems and stored in water for 24 h and 6 months. Three bonded teeth were selected for each group for nanoindentation methodology to obtain the nanohardness and modulus values (n = 3), while seven bonded teeth each group were used for mu TBS (n = 7). Data were analyzed by two-way ANOVA and Tukey's test (alpha = 0.05). Spearman correlation between nanohardness and modulus and mu TBS values was also calculated. Nanohardness and Young's modulus values for the dentin and hybrid layer were not significantly different regardless of the adhesive system or water storage periods (p > 0.05). Nanohardness and Young's modulus values for the adhesive layer were significantly higher for SB2 than for SBMP, CSE, and CS3 systems in both water storage periods. The mu TBS values for SBMP and CSE were significantly higher than for SB2 and CS3 in both storage periods. An inverse correlation between Young's modulus and mu TBS was observed for the adhesive layer. The water storage periods did not alter nanohardness, Young's modulus, and mu TBS of adhesives. The adhesive layer of SB2 showed the highest nanohardness and Young's modulus, but the highest dentin bond strength was obtained with SBMP and CSE. Thus, a lower Young's modulus yielded high bond strength. The inverse correlation between the Young's modulus of adhesive systems and dentin bond strength suggests adequate resistance of the adhesive to elastic deformation under stress, which are important properties to predict the success of the dental restoration.21410551062Coordination for the Improvement of Higher Education Personnel (CAPES) [1777-2014]Department of Restorative Dentistry, Division of Dental Materials, Piracicaba Dental School, State University of Campinas, UNICAMP, Piracicaba, SP, BrazilCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Bonding Performance Of Experimental Bioactive/biomimetic Self-etch Adhesives Doped With Calcium-phosphate Fillers And Biomimetic Analogs Of Phosphoproteins

This study examined the bonding performance and dentin remineralization potential of an experimental adhesive containing calcium-phosphate (Ca/P) micro-fillers, and self-etching primers doped with phosphoprotein biomimetic analogs (polyacrylic acid-(PAA) and/or sodium trimetaphosphate-(TMP)). Methods: Experimental self-etching primers doped with biomimetic analogs (PAA and/or TMP), and an adhesive containing Ca2+, PO4-3-releasing micro-fillers (Ca/P) were formulated. Sound human dentin specimens were bonded and cut into sticks after aging (24 h or 6 months) under simulated pulpal pressure (20 cm H2O), and tested for microtensile bond strength (mu TBS). Results were analyzed using two-way ANOVA and Tukey's test (p < 0.05). Interfacial silver nanoleakage was assessed using SEM. Remineralization of EDTA-demineralized dentin was assessed through FTIR and TEM ultrastructural analysis. Results: Application of the Ca/P-doped adhesive with or without dentin pre-treatments with the primer containing both biomimetic analogs (PAA and TMP) promoted stable mTBS over 6 months. Conversely, mTBS of the control primer and filler-free adhesive significantly decreased after 6 months. Nanoleakage decreased within the resin-dentin interfaces created using the Ca/P-doped adhesives. EDTA-demineralized dentin specimens treated the Ca/P-doped adhesive and the primer containing PAA and TMP showed phosphate uptake (FTIR analysis), as well as deposition of needle-like crystallites at intrafibrillar level (TEM analysis). Significance: The use of Ca/P-doped self-etching adhesives applied in combination with analogs of phosphoproteins provides durable resin-dentin bonds. This approach may represent a suitable bonding strategy for remineralization of intrafibrillar dentin collagen within the resin-dentin interface. (C) 2016 Elsevier Ltd. All rights reserved.527986Programa de Consolidacion de Indicadores: Fomento Plan Estatal CEU-UCH [PEST-1408, INDI1527

Effect Of Different Photoinitiators And Reducing Agents On Cure Efficiency And Color Stability Of Resin-based Composites Using Different Led Wavelengths

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Objectives: To evaluate the effect of photoinitiators and reducing agents on cure efficiency and color stability of resin-based composites using different LED wavelengths. Methods: Model resin-based composites were associated with diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO), phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO) or camphorquinone (CQ) associated with 2-(dimethylamino) ethyl methacrylate (DMAEMA), ethyl 4-(dimethyamino) benzoate (EDMAB) or 4-(N,N-dimethylamino) phenethyl alcohol (DMPOH). A narrow (Smartlite, Dentisply) and a broad spectrum (Bluephase G2, Ivoclar Vivadent) LEDs were used for photo-activation (20 J/cm(2)). Fourier transform infrared spectroscopy (FT-IR) was used to evaluate the cure efficiency for each composite, and CIELab parameters to evaluated color stability (Delta E-00) after aging. The UV-vis absorption spectrophotometric analysis of each photoinitiator and reducing agent was determined. Data were analyzed using two-way ANOVA and Tukey's test for multiple comparisons (alpha = 0.05). Results: Higher cure efficiency was found for type-I photoinitiators photo-activated with a broad spectrum light, and for CQ-systems with a narrow band spectrum light, except when combined with an aliphatic amine (DMAEMA). Also, when combined with aromatic amines (EDMAB and DMPOH), similar cure efficiency with both wavelength LEDs was found. TPO had no cure efficiency when light-cured exclusively with a blue narrowband spectrum. CQ-systems presented higher color stability than type-I photoinitiators, especially when combined with DMPOH. Conclusions: After aging, CQ-based composites became more yellow and BAPO and TPO lighter and less yellow. However, CQ-systems presented higher color stability than type-I photoinitiators, as BAPO-and TPO-, despite their higher cure efficiency when photo-activated with corresponding wavelength range. Clinical Significance: Color matching is initially important, but color change over time will be one of the major reasons for replacing esthetic restorations; despite the less yellowing of these alternative photoinitiators, camphorquinone presented higher color stability. (C) 2015 Elsevier Ltd. All rights reserved.431215651572Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2013/04241-2

In-vivo Evaluation Of The Surface Roughness And Morphology Of Enamel After Bracket Removal And Polishing By Different Techniques

Introduction: The aim of this study was to evaluate the surface roughness and morphology of enamel with a surface roughness tester and scanning electron microscopy after the removal of metal brackets and polishing. Methods: Ten orthodontic patients were selected for the study. At the conclusion of orthodontic treatment, their metal brackets were removed. For each patient, teeth on one side of the mouth were randomly chosen for finishing and polishing with aluminum oxide discs (n = 10). Teeth on the other side were finished with multilaminated carbide burs (n = 10). Dental replicas (before and after tooth polishing) were obtained with epoxy resin. Three surface roughness measurements were made in different directions with an angle of 120 degrees among them, and a mean for each dental replica was calculated. The roughness data were statistically evaluated by repeated-measurements analysis of variance. Three specimens from each group were also used for scanning electron microscopy analysis. Results: After resin removal, the average roughness in the carbide bur group (0.31 mu m) was significantly greater than that in the aluminum oxide disc group (0.25 mm). Conclusions: The aluminum oxide disc polishing system resulted in less enamel roughness than did the multilaminated carbide bur system

The Effect Of Combining Photoinitiator Systems On The Color And Curing Profile Of Resin-based Composites

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)To evaluate the effect of combining camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) on the color and curing profile of resin-based composites. Methods. Experimental composites were produced with different CQ and TPO molar concentrations: CQ-only, 3CQ:1TPO, 1CQ:1TPO, 1CQ:3TPO, and TPO-only. Polywave LED was characterized using a beam profiler. Block-shaped samples (5 mm x 5 mm x 3 mm depth) were cured in a custom-designed mold with a polywave LED positioned to compare the regions exposed to the 420-495 nm and 380-420 nm LED emittances. To map the cure profile, degree of conversion (DC) of longitudinal cross-sections from each block were evaluated by FT-NIR. Color, light-transmittance and light-absorption during curing were evaluated on specimens 1-3 mm thick. Data were analyzed using ANOVA/Tukey's test (alpha = 0.05; beta = 0.2). Results. Though the polywave LED beam profile was non-uniform, up to a depth of 2 mm no differences in DC were found among the composites containing CQ with TPO added up to 50%, regardless of the position under the curing tip. Composites with higher TPO concentration showed a decrease in DC beginning with a depth of 1 mm, while composites with higher or similar CQ concentrations did not show decreased DC until a depth of 3 mm. Higher TPO concentration reduced initial yellowness and color change after curing; and lower CQ concentration decreased light-absorption at greater depths. Significance. The combination of CQ with TPO added up to 50% reduced the yellowness and color change of composites after curing without affecting cure efficiency up to a depth of 2 mm. (C) 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.321012091217FAPESP [2013/04241-2, 2016/06019-3]BEPE [03028-6]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP