Vegetation reclamation in oil-sands requires a consistent and adequate supply of seeds of native shrubs. However, annual seed production is erratic and seeds are usually short lived and insufficient for the reclamation projects. Seeds of six native shrub species including: Prunus virginiana, Prunus pensylvanica, Arctostaphylos uva-ursi, Shepherdia canadensis, Cornus sericea, and Viburnum edule were used to analyze physiological changes during storage and artificial aging processes. The shrub seeds were studied for one year during storage under eight different combinations of temperature (-20, 4, 22.5 °C), atmosphere (Air / N2) and relative humidity (RH; 7-8 % / 3-4 %). No significant differences were detected among the storage parameters after one year; however, sub-zero and N2 environments showed a potential in maintaining a higher seed vigour during storage. In the artificial aging experiment, seeds were subjected to 45 oC, 60 % RH for 5-25 d. For most shrub species, the seed viability decreased significantly after 10-15 d artificial aging and was down to 0 % after 20 d. The germination percentage declined already after 5 d; therefore, there was a delay in detecting viability loss using the tetrazolium test. Non-aged seeds and aged seeds of most collections showed significantly different seedling lengths, which indicated a negative effect of accelerated aging process on the seedling growth. The electrolyte conductivity, as well as seed dehydrin protein expression, is strongly correlated with the seed vigour, which can be used as seed quality assessment methods in seed longevity predicting. A loss of membrane integrity occurred during the accelerated seed aging processes, as indicated by an increased electrolyte conductivity that was negatively correlated with the seed viability and germination. During artificial aging process, heat stress of Prunus virginiana induced expression of dehydrins with a molecular mass of 27 kDa, which reached a detectable level after 5 d. The storage protocol developed in this study would benefit the adequate supply of viable shrub seeds for reclamation. With species-specific parameters taken into consideration, the artificial aging technique to predict seed longevity can be further expanded to other non-crop species used in reclamation of lands after oil extraction.

Vibrations are very common phenomenon. It influences structures and generates acoustic noise which might be harmful to human beings. The vibration isolator was invented to reduce the effect from vibrations. However, the behavior of rubber material, which many vibration isolators are made of, is hard to predict. Consequently, vibration tests are needed to obtain the dynamic properties of rubber isolator.In this case, a six-year old LORD 2204-5 rubber isolator provided by Atlas Copco was tested. The aim of this paper is to obtain the FRF (Frequency Response Function) diagram which can describe the property of the rubber material. Moreover, the influence of aging of rubber material on the dynamic properties was studied.As the vibration test should simulate the working environment of the isolators that are both a static load from the structure and a dynamic force from the engine, a new excitation method was designed. The camshaft with the shape of an epitrochoid induced the sinusoidal signal of the isolator and the frame transferred the static load from the hydraulic machine. The artificial aging was performed in a hot air oven in 90°C for 42 hours, which according to Arrhenius equation should be equivalent to six years of natural aging. The vibration isolator was tested again after being aged.The obtained data showed that the aging process decreased the stiffness of the material. The results were corresponding with other studies regarding aging of rubber.

O presente trabalho teve como objetivo analisar “in vitro” a alteração de cor e a rugosidade superficial de uma resina composta (Charisma®) submetidas a tratamento clareador com agente clareador Lase Peroxide Sensy® (CC) e grupo controle sem tratamento clareador (SCL), após envelhecimento (EAA) em função do tempo, realizando-se avaliação superficial complementar por meio de Microscopia Eletrônica de Varredura (MEV) e EDX. Os corpos-de-prova (n=15) foram confeccionados com o auxílio de uma matriz de Teflon nas dimensões de 11x2,0mm, polidos com discos Soft Lex®, na seqüência de abrasividade decrescente e armazenados em saliva artificial a 37ºC (±1ºC), até os momentos de serem submetidos aos tratamentos propostos e à realização das leituras de alteração de cor e rugosidade superficial, nos tempos: 24 horas após a confecção (T0), após envelhecimento artificial acelerado (T1), 24 horas após clareamento (T2), 7dias (T3) e 1 mês após clareamento (T4). As leituras de alteração de cor foram obtidas com o auxílio do aparelho Espectrofotômetro (PCB6807BYK GARDNER) e para as leituras de rugosidade superfícial foi utilizado o Rugosímetro Mitutoyo SJ201P. Os dados foram submetidos à Análise de Variância ANOVA (p≤0,05). Os resultados obtidos foram: a) o fator Tempo teve efeito estatisticamente significante sobre as variáveis ΔE* (T1=T2=T3; T1=T4), L* (T0<T1=T2=T3=T4), a* (T0>T1=T2; T1=T3=T4; T4>T2), b* (T0>T1=T2=T3; T4=T3=T1; T2<T4) e rugosidade superficial (μm) (T0<T1,T2,T3,T4; T1=T2; T1<T3=T4; T2=T3=T4; b) para o fator tratamento com relação a ΔE* e fator L*(CC>SCL), para os fatores a* e b*(CC<SC), c) a interação Tratamento x Tempo não apresentou diferença estatisticamente significante para as variáveis ΔE*, L*, a*, b* e rugosidade superficial, d) as superfícies após EAA apresentaram alterações d) não houve mudanças no EDX antes e após os tratamentos. Conclui-se que a resina Charisma®, apresentou alteração de cor (ΔE*>3,3) e uma estabilidade na rugosidade superficial a partir de T2. / The current study in vitro evaluated the color change and surface roughness of the composite resin Charisma® cleared with Lase Peroxide Sensy® (CCL) and control without bleaching (SCL) after accelerated artificial aging (EAA) as a function of time, performing additional surface evaluation by scanning electron microscopy (MEV) and EDX. To obtain the color change and surface roughness a Spectrophotometer (PCB 6807 BYK GARDNER) and rugosimeter (Mitutoyo SJ- 201P) were employed respectively. Measurements were carried out at five times: 24 hours after preparation (T0), after artificial accelerated aging (T1), 24 hours after bleaching (T2), 7days (T3) and 1 month after bleaching (T4). The specimens (n=15) were prepared with aid of a Teflon (10-mmin diameter and 2mm thick). The specimens were polished with discs Soft Lex®, following abrasiveness decreased, being stored in artificial saliva at 37ºC (±1ºC) until the time of undergoing the proposed treatments and the measurements. The data obtained were submitted to ANOVA parametric test (p ≤ 0.05). The results were: a) time factor had a statistically significant effect on the variables ΔE* (T1 = T2 = T3, T1 = T4), L*(T0 <T1 = T2 = T3 = T4), a* (T0 > T1 = T2; T1=T3 =T4, T4>T2), b* (T0> T1=T2=T3, T4=T3=T1; T2<T4) and roughness(μm) (T0<T1,T2, T3,T4; T1 = T2; T1<T3=T4; T2=T3=T4), b) for treatment factor ΔE* and L* (CC> SCL) for the factors a*and b* (CC <SC), c) Treatment x Time interaction showed no statistically significant difference for the variables ΔE*, L*, a*, b* and surface roughness, d) after EAA the surfaces change d) before and after EAA dont have changes. It is concluded that the resin Charisma®, presented color change (ΔE *> 3.3) and surface roughness stability from T2.

O propósito deste estudo foi comparar a resistência ao cisalhamento (RC) e o índice de remanescente adesivo (IRA) após Envelhecimento Artificial Acelerado (EAA) de bráquetes ortodônticos metálicos fixados com compósitos autopolimerizável (Concise Ortodôntico - CS, 3M Unitek) e fotoativado (Transbond Plus Color Change - TPCC, 3M Unitek) com diferentes tratamentos de superfície do esmalte. Foram selecionados 60 pré-molares humanos recém extraídos, que tiveram suas raízes embutidas em resina acrílica ativada quimicamente de forma que a face vestibular ficasse perpendicular ao plano horizontal. Estas foram limpas com pedra pomes e água por 10 segundos, lavadas e secas. Os dentes foram separados aleatoriamente em 5 grupos (n=12), segundo o tipo de tratamento de superfície do esmalte, e do compósito utilizado para fixação dos bráquetes: Grupo I - ácido fosfórico a 37% (Dental Gel, Dentsply) e CS; Grupo II - ácido fosfórico a 37% + Primer e CS; Grupo III - ácido fosfórico a 37% e TPCC; Grupo IV - ácido fosfórico a 37% + XT Primer (3M Unitek) e TPCC; e Grupo V Transbond Plus Self Etching Primer - SEP (3M Unitek) e TPCC. Após 24h da colagem dos bráquetes, metade das amostras de cada grupo (n=6) foi submetida ao EAA por 960 horas. Todas as amostras foram submetidas ao ensaio de resistência ao cisalhamento com cinzel em máquina universal de ensaios (DL 200, EMIC) na velocidade de 0,5 mm/min. Após a descolagem dos bráquetes, causada pelo teste de resistência ao cisalhamento, o IRA foi avaliado em lupa (10X) e quantificado a partir de escore (0-3). Os dados foram analisados estatisticamente (2-way ANOVA, Bonferroni, p<0,05) e verificou-se que não houve diferença estatisticamente significante entre os Grupos em função do EAA (p>0,05). Quando comparados os sistemas adesivos utilizados, verificou-se que o Grupo II sem EAA, apresentou a maior média de RC, resultado estatisticamente significante (p<0,05) em relação aos grupos III e V, que apresentou a menor média de RC. Quanto ao IRA, todos os grupos sem EAA apresentaram maior frequência do índice 3. Com EAA, houve aumento de frequência dos índices 1 e 2. Concluiu-se que o EAA não influenciou a RC de bráquetes ao dente, mas diminuiu a área de remanescente adesivo sobre o dente. / The purpose of this study was to compare the shear bond strength (SBS) and the adhesive remnant index (ARI) after Accelerated Artificial Aging (AAA) of metal orthodontic brackets bonded with self-polymerizing (Concise Ortodôntico - CS, 3M Unitek) and light activated (Transbond Plus Color Change - TPCC, 3M Unitek) composites, to enamel with different surface treatments. Sixty recently-extracted human premolars were selected. Their roots were embedded in chemically activated acrylic resin so that the vestibular face was perpendicular to the horizontal plane. They were cleaned with pumice stone and water for 10 seconds, washed and dried. The teeth were randomly separated into 5 groups (n=12), according to the type of enamel surface treatment, and composite used for bracket bonding: Group I - 37% phosphoric acid (Dental Gel, Dentsply) and CS; Group II - 37% phosphoric acid + Primer and CS; Group III - 37% phosphoric acid and TPCC; Group IV - 37% phosphoric acid + XT Primer (3M Unitek) and TPCC; and Group V Transbond Plus Self Etching Primer - SEP (3M Unitek) and TPCC. Twenty-four hours after bracket bonding, half the samples from each group (n=6) were submitted to AAA for 960 hours. All the samples were submitted to shear bond strength testing with a chisel, in a Universal Test Machine (DL 200, EMIC) at a speed of 0.5 mm/min. After bracket debonding caused by the shear bond strength test, the ARI was evaluated under a loupe (10X) and quantified according to a score (0-3). Data were statistically analyzed (2-way ANOVA, Bonferroni, p<0.05) and it was verified that there was no statistically significant difference among Groups as a function of AAA (p>0.05). When comparing the adhesive systems used, it was verified that Group II without AAA showed the highest mean SBS, a statistically significant result (p<0.05) in comparison with Groups III and V, which showed the lowest mean SBS. As regards ARI, all the groups without AAA showed higher frequency of Index 3. With AAA, there was increased frequency of indexes 1 and 2. It was concluded that AAA did not influence SBS of brackets to the tooth, but diminished the area of adhesive remnant on the tooth.

While the oxidation of binders in hot mix asphalt (HMA) pavements and its subsequent detrimental effects on pavement life have been well recognized in the last few years, many important issues have not yet been investigated. Understanding how best to design mixtures taking this phenomenon into account and achieving maximum durability is an important and complex issue. This study was aimed at characterizing the effects of oxidative aging on durability in terms of mixture fatigue resistance of laboratory mixed-laboratory compacted (LMLC) samples. Direct tension tests were conducted on HMA samples to measure mixture stiffness and a Modified Calibrated Mechanistic with Surface Energy (CMSE*) analysis method was used to predict fatigue life. The effect of various mix design parameters was evaluated to understand their importance with respect to the aging phenomena and mixture fatigue resistance. Analysis of the results showed that aging has a significant negative effect on mixture fatigue resistance. Considerable increase in the stiffness modulus (Eve) of the mixtures was observed with age for all three mixtures analyzed. Air voids (AV) played a substantial role in affecting the fatigue resistance with aging, but a difference of 0.5% in binder content near the optimum level did not statistically change mixture durability in terms of fatigue resistance with aging. For the three mixtures in Texas included in this study, when comparing Eve, one month of artificial aging in the laboratory was equivalent to 10.5 months of natural aging in the field. A good correlation was also found between the Eve of the mixture and the Carbonyl Area (CA) and Dynamic Shear Rheometer (DSR) function of the extracted binder. Thus, a connection exists between the properties of the extracted binder, laboratory mixtures and field mixtures. This relationship will facilitate development of a more mechanistic aging component in pavement performance prediction models.

O propósito deste estudo foi comparar a resistência ao cisalhamento (RC) e o índice de remanescente adesivo (IRA) após Envelhecimento Artificial Acelerado (EAA) de bráquetes ortodônticos metálicos fixados com compósitos autopolimerizável (Concise Ortodôntico - CS, 3M Unitek) e fotoativado (Transbond Plus Color Change - TPCC, 3M Unitek) com diferentes tratamentos de superfície do esmalte. Foram selecionados 60 pré-molares humanos recém extraídos, que tiveram suas raízes embutidas em resina acrílica ativada quimicamente de forma que a face vestibular ficasse perpendicular ao plano horizontal. Estas foram limpas com pedra pomes e água por 10 segundos, lavadas e secas. Os dentes foram separados aleatoriamente em 5 grupos (n=12), segundo o tipo de tratamento de superfície do esmalte, e do compósito utilizado para fixação dos bráquetes: Grupo I - ácido fosfórico a 37% (Dental Gel, Dentsply) e CS; Grupo II - ácido fosfórico a 37% + Primer e CS; Grupo III - ácido fosfórico a 37% e TPCC; Grupo IV - ácido fosfórico a 37% + XT Primer (3M Unitek) e TPCC; e Grupo V Transbond Plus Self Etching Primer - SEP (3M Unitek) e TPCC. Após 24h da colagem dos bráquetes, metade das amostras de cada grupo (n=6) foi submetida ao EAA por 960 horas. Todas as amostras foram submetidas ao ensaio de resistência ao cisalhamento com cinzel em máquina universal de ensaios (DL 200, EMIC) na velocidade de 0,5 mm/min. Após a descolagem dos bráquetes, causada pelo teste de resistência ao cisalhamento, o IRA foi avaliado em lupa (10X) e quantificado a partir de escore (0-3). Os dados foram analisados estatisticamente (2-way ANOVA, Bonferroni, p<0,05) e verificou-se que não houve diferença estatisticamente significante entre os Grupos em função do EAA (p>0,05). Quando comparados os sistemas adesivos utilizados, verificou-se que o Grupo II sem EAA, apresentou a maior média de RC, resultado estatisticamente significante (p<0,05) em relação aos grupos III e V, que apresentou a menor média de RC. Quanto ao IRA, todos os grupos sem EAA apresentaram maior frequência do índice 3. Com EAA, houve aumento de frequência dos índices 1 e 2. Concluiu-se que o EAA não influenciou a RC de bráquetes ao dente, mas diminuiu a área de remanescente adesivo sobre o dente. / The purpose of this study was to compare the shear bond strength (SBS) and the adhesive remnant index (ARI) after Accelerated Artificial Aging (AAA) of metal orthodontic brackets bonded with self-polymerizing (Concise Ortodôntico - CS, 3M Unitek) and light activated (Transbond Plus Color Change - TPCC, 3M Unitek) composites, to enamel with different surface treatments. Sixty recently-extracted human premolars were selected. Their roots were embedded in chemically activated acrylic resin so that the vestibular face was perpendicular to the horizontal plane. They were cleaned with pumice stone and water for 10 seconds, washed and dried. The teeth were randomly separated into 5 groups (n=12), according to the type of enamel surface treatment, and composite used for bracket bonding: Group I - 37% phosphoric acid (Dental Gel, Dentsply) and CS; Group II - 37% phosphoric acid + Primer and CS; Group III - 37% phosphoric acid and TPCC; Group IV - 37% phosphoric acid + XT Primer (3M Unitek) and TPCC; and Group V Transbond Plus Self Etching Primer - SEP (3M Unitek) and TPCC. Twenty-four hours after bracket bonding, half the samples from each group (n=6) were submitted to AAA for 960 hours. All the samples were submitted to shear bond strength testing with a chisel, in a Universal Test Machine (DL 200, EMIC) at a speed of 0.5 mm/min. After bracket debonding caused by the shear bond strength test, the ARI was evaluated under a loupe (10X) and quantified according to a score (0-3). Data were statistically analyzed (2-way ANOVA, Bonferroni, p<0.05) and it was verified that there was no statistically significant difference among Groups as a function of AAA (p>0.05). When comparing the adhesive systems used, it was verified that Group II without AAA showed the highest mean SBS, a statistically significant result (p<0.05) in comparison with Groups III and V, which showed the lowest mean SBS. As regards ARI, all the groups without AAA showed higher frequency of Index 3. With AAA, there was increased frequency of indexes 1 and 2. It was concluded that AAA did not influence SBS of brackets to the tooth, but diminished the area of adhesive remnant on the tooth.

Orientador: Marco Eustáquio de Sá / Banca: Kuniko Iwamoto Haga / Banca: Marcelo Andreotti / Banca: Valdemir Antonio Laura / Banca: Ceci Castilho Custódio / Resumo: O uso de sementes de Brachiaria brizantha tem aumentado, no entanto a qualidade fisiológica das sementes disponibilizadas ao produtor é ainda um fator limitante para um bom desempenho das culturas. O objetivo do trabalho foi verificar os efeitos do condicionamento fisiológico (CF), escarificação química e diferentes períodos de envelhecimento artificial na qualidade fisiológica, superação de dormência e lixiviação de íons no exsudato do teste de condutividade elétrica, em sementes de B. brizantha cv. MG-5 Vitória. O trabalho foi conduzido no Laboratório de Análises de Sementes da Unesp - Campus de Ilha Solteira. O delineamento experimental utilizado foi o inteiramente casualizados e o estudo foi constituído por três experimentos. Experimento 1 - verificou-se o efeito do condicionamento osmótico (CO) com soluções mistas constituídas por Polietileno glicol 8000 + solução com nutriente ou regulador de crescimento ou bioestimulante e associação entres eles. Experimento 2 - verificou-se os efeitos de diferentes períodos de envelhecimento artificial. Experimento 3 - verificou-se os efeitos da escarificação química, diferentes períodos de envelhecimento artificial e CF. Conclui-se que o aumento dos teores de potássio e cálcio nas sementes é proporcionado através do CO com KNO3 e Ca(NO3)2, respectivamente. A escarificação química é um método eficaz para superação de dormência, porém as sementes apresentam menor potencial de armazenamento. A utilização da escarificação com um período curto de exposição à alta temperatura e umidade é eficaz para o aumento da expressão do vigor e superação de dormência das sementes. O CF com KNO3 atua positivamente na qualidade fisiológica das sementes e proporciona menor perda de constituintes celulares. O lixiviado de potássio parece ser um parâmetro adequado para a identificação da qualidade ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The use of Brachiaria brizantha seeds has been increased, yet the physiological quality of seed available to farmer is still a limiting factor for good crop performance. The objective was to investigate the effects of priming, chemical scarification and different periods of artificial aging on physiological quality, dormancy and leaching of ions in the exudate of the electrical conductivity test seeds of B. brizantha cv. MG-5 Vitória. The work was carried out at the Laboratory of Seed Analysis - Unesp Ilha Solteira. The experimental design was completely randomized and the study consisted of three experiments. Experiment 1 - it has the effect of priming mixed solutions consisting of polyethylene glycol 8000 + with nutrient solution or growth regulator or plant growth regulator and association among them. Experiment 2 - it has the effect of different periods of artificial aging. Experiment 3 - it has the effect of chemical scarification, different periods of aging and priming. We conclude that increased levels of potassium and calcium in the seed provided by the priming with KNO3 and Ca(NO3) 2, respectively. Chemical scarification is an effective method for breaking dormancy, but the seeds have a lower storage potential. The use of scarification with a short period of exposure to high temperature and humidity is effective to increase the expression of vigor and dormancy of seeds. Priming with KNO3 acts positively on seed physiological quality and provides lower loss of cellular constituents. The leaching of potassium seems to be a suitable parameter for identifying the physiological quality of seeds scarified B. brizantha / Doutor

O presente trabalho teve como objetivo analisar &ldquo;in vitro&rdquo; a alteração de cor e a rugosidade superficial de uma resina composta (Charisma®) submetidas a tratamento clareador com agente clareador Lase Peroxide Sensy® (CC) e grupo controle sem tratamento clareador (SCL), após envelhecimento (EAA) em função do tempo, realizando-se avaliação superficial complementar por meio de Microscopia Eletrônica de Varredura (MEV) e EDX. Os corpos-de-prova (n=15) foram confeccionados com o auxílio de uma matriz de Teflon nas dimensões de 11x2,0mm, polidos com discos Soft Lex®, na seqüência de abrasividade decrescente e armazenados em saliva artificial a 37ºC (±1ºC), até os momentos de serem submetidos aos tratamentos propostos e à realização das leituras de alteração de cor e rugosidade superficial, nos tempos: 24 horas após a confecção (T0), após envelhecimento artificial acelerado (T1), 24 horas após clareamento (T2), 7dias (T3) e 1 mês após clareamento (T4). As leituras de alteração de cor foram obtidas com o auxílio do aparelho Espectrofotômetro (PCB6807BYK GARDNER) e para as leituras de rugosidade superfícial foi utilizado o Rugosímetro Mitutoyo SJ201P. Os dados foram submetidos à Análise de Variância ANOVA (p&le;0,05). Os resultados obtidos foram: a) o fator Tempo teve efeito estatisticamente significante sobre as variáveis &Delta;E* (T1=T2=T3; T1=T4), L* (T0&lt;T1=T2=T3=T4), a* (T0&gt;T1=T2; T1=T3=T4; T4&gt;T2), b* (T0&gt;T1=T2=T3; T4=T3=T1; T2&lt;T4) e rugosidade superficial (&mu;m) (T0&lt;T1,T2,T3,T4; T1=T2; T1&lt;T3=T4; T2=T3=T4; b) para o fator tratamento com relação a &Delta;E* e fator L*(CC&gt;SCL), para os fatores a* e b*(CC&lt;SC), c) a interação Tratamento x Tempo não apresentou diferença estatisticamente significante para as variáveis &Delta;E*, L*, a*, b* e rugosidade superficial, d) as superfícies após EAA apresentaram alterações d) não houve mudanças no EDX antes e após os tratamentos. Conclui-se que a resina Charisma®, apresentou alteração de cor (&Delta;E*&gt;3,3) e uma estabilidade na rugosidade superficial a partir de T2. / The current study in vitro evaluated the color change and surface roughness of the composite resin Charisma® cleared with Lase Peroxide Sensy® (CCL) and control without bleaching (SCL) after accelerated artificial aging (EAA) as a function of time, performing additional surface evaluation by scanning electron microscopy (MEV) and EDX. To obtain the color change and surface roughness a Spectrophotometer (PCB 6807 BYK GARDNER) and rugosimeter (Mitutoyo SJ- 201P) were employed respectively. Measurements were carried out at five times: 24 hours after preparation (T0), after artificial accelerated aging (T1), 24 hours after bleaching (T2), 7days (T3) and 1 month after bleaching (T4). The specimens (n=15) were prepared with aid of a Teflon (10-mmin diameter and 2mm thick). The specimens were polished with discs Soft Lex®, following abrasiveness decreased, being stored in artificial saliva at 37ºC (±1ºC) until the time of undergoing the proposed treatments and the measurements. The data obtained were submitted to ANOVA parametric test (p &le; 0.05). The results were: a) time factor had a statistically significant effect on the variables &Delta;E* (T1 = T2 = T3, T1 = T4), L*(T0 &lt;T1 = T2 = T3 = T4), a* (T0 &gt; T1 = T2; T1=T3 =T4, T4&gt;T2), b* (T0&gt; T1=T2=T3, T4=T3=T1; T2&lt;T4) and roughness(&mu;m) (T0&lt;T1,T2, T3,T4; T1 = T2; T1&lt;T3=T4; T2=T3=T4), b) for treatment factor &Delta;E* and L* (CC&gt; SCL) for the factors a*and b* (CC &lt;SC), c) Treatment x Time interaction showed no statistically significant difference for the variables &Delta;E*, L*, a*, b* and surface roughness, d) after EAA the surfaces change d) before and after EAA dont have changes. It is concluded that the resin Charisma®, presented color change (&Delta;E *> 3.3) and surface roughness stability from T2.

O objetivo deste estudo foi avaliar a estabilidade de cor de cimentos resinosos para fixação de restaurações cerâmicas em diferentes espessuras submetidas ao envelhecimento artificial acelerado (EAA). Foram utilizados 60 molares humanos hígidos, cujas porções radiculares foram incluídas em matriz de PVC (15 mm de diâmetro) com resina acrílica e as faces oclusais foram planificadas, 30 em esmalte e 30 até dentina, sendo que 10 dentes de cada substrato foram considerados gruposcontrole para os dentes restaurados. Foram obtidos 40 corpos de prova em cerâmica (IPS e-max Ceram, Ivoclar Vivadent), com 0,5 mm e 1,0 mm, que foram separados aleatoriamente em dois grupos (n=10) segundo o tipo de cimento resinoso dual utilizado para fixação: convencional (Variolink II, Ivoclar/Vivadent) ou auto-adesivo (Rely-X Unicem, 3M ESPE). Além desses, foram obtidos 10 corpos de prova de cada cimento resinoso (0,5mm), considerado grupo-controle para os materiais. Todas as amostras foram mantidas em estufa a 37ºC por 24h, após o qual foram realizadas as leituras de cor iniciais (Vita EasyShade, VITA). Em seguida, foram submetidas ao EAA por 580 horas, após o qual novas leituras de cor foram realizadas. Foi avaliada estabilidade de cor e a luminosidade. Os dados de estabilidade de cor (&Delta;E) e luminosidade (&Delta;L) obtidos foram submetidos a análise estatística (2-way ANOVA, Bonferroni, p<0,05) e a comparação dos materiais com os grupos controles foi realizada utilizando 1-way ANOVA e teste de Tukey (p<0,05). O cimento dual convencional apresentou maior alteração de cor e luminosidade quando sob a restauração de 0,5mm, diferente estatisticamente (p<0,05) de restaurações de 1,0mm. Não houve diferença estatisticamente significante (p>0,05) quando comparados os materiais. Quando analisadas a estabilidade de cor e luminosidade dos grupos com restaurações em relação aos grupos-controle, verificou-se que ambos os cimentos apresentaram maiores alterações, diferente estatisticamente (p<0,05) dos demais grupos, com exceção ao grupo de 0,5mm em relação ao Grupo esmalte quando analisado o cimento dual convencional (p>0,05). Concluiu-se que quanto menor a espessura da restauração, maior a alteração de cor e de luminosidade do cimento dual convencional. As alterações do cimento autoadesivo não dependem da espessura da restauração. / The aim of this study was to evaluate the color stability of resin cements for luting ceramic restorations with different thicknesses submitted to accelerated artificial aging (AAA). Sixty sound human molars had their root portions embedded in PVC rings (15-mm diameter) with acrylic resin. Their occlusal surfaces were flattened according two substrates: 30 surfaces until enamel and 30 until dentin. Then, 10 teeth of each substrate were considered as control groups for restored teeth. Forty specimens of ceramic (IPS e-max Ceram, Ivoclar Vivadent) were obtained with two different thicknesses (0.5 mm and 1.0 mm) and were randomly separated into two groups (n = 10) according to the type of the Dual resin cement used for luting: conventional (Variolink II, Ivoclar / Vivadent) or self-adhesive (Rely-X Unicem, 3M ESPE). Also, 10 specimens (0.5 mm) of each cement were obtained to be considered as control groups for materials. All specimens were stored at 37º C for 24 hours, and initial color readings (Vita Easyshade, VITA) were performed. Then, they were submitted to AAA for 580 hours, and final color readings were taken. Color stability and brightness were evaluated. Data of color stability (&Delta;E) and brightness (&Delta;L) were statistically analyzed (2- way ANOVA, Bonferroni, p<0.05) and the comparison of materials with control groups was performed using one-way ANOVA and Tukeys test (p<0.05). The conventional dual cement showed the greatest change in color and brightness when under restorations of 0.5 mm, statistically different (p<0.05) to restorations of 1.0 mm. There was no statistically significant difference (p>0.05) when comparing materials. When analyzing the color stability and brightness of restorations groups compared to control groups, both cements showed greater changes, statistically different (p<0.05), than other groups, except for the group of 0.5 mm in relation to enamel group when the dual conventional cement was analyzed (p>0.05). It was concluded that the smaller the thickness of the restoration, the greater the color and brightness changes of the dual conventional cement. Changes of the self-adhesive cement do not depend on the thickness of the restoration.

O objetivo deste estudo foi avaliar a estabilidade de cor de cimentos resinosos para fixação de restaurações cerâmicas em diferentes espessuras submetidas ao envelhecimento artificial acelerado (EAA). Foram utilizados 60 molares humanos hígidos, cujas porções radiculares foram incluídas em matriz de PVC (15 mm de diâmetro) com resina acrílica e as faces oclusais foram planificadas, 30 em esmalte e 30 até dentina, sendo que 10 dentes de cada substrato foram considerados gruposcontrole para os dentes restaurados. Foram obtidos 40 corpos de prova em cerâmica (IPS e-max Ceram, Ivoclar Vivadent), com 0,5 mm e 1,0 mm, que foram separados aleatoriamente em dois grupos (n=10) segundo o tipo de cimento resinoso dual utilizado para fixação: convencional (Variolink II, Ivoclar/Vivadent) ou auto-adesivo (Rely-X Unicem, 3M ESPE). Além desses, foram obtidos 10 corpos de prova de cada cimento resinoso (0,5mm), considerado grupo-controle para os materiais. Todas as amostras foram mantidas em estufa a 37ºC por 24h, após o qual foram realizadas as leituras de cor iniciais (Vita EasyShade, VITA). Em seguida, foram submetidas ao EAA por 580 horas, após o qual novas leituras de cor foram realizadas. Foi avaliada estabilidade de cor e a luminosidade. Os dados de estabilidade de cor (&Delta;E) e luminosidade (&Delta;L) obtidos foram submetidos a análise estatística (2-way ANOVA, Bonferroni, p<0,05) e a comparação dos materiais com os grupos controles foi realizada utilizando 1-way ANOVA e teste de Tukey (p<0,05). O cimento dual convencional apresentou maior alteração de cor e luminosidade quando sob a restauração de 0,5mm, diferente estatisticamente (p<0,05) de restaurações de 1,0mm. Não houve diferença estatisticamente significante (p>0,05) quando comparados os materiais. Quando analisadas a estabilidade de cor e luminosidade dos grupos com restaurações em relação aos grupos-controle, verificou-se que ambos os cimentos apresentaram maiores alterações, diferente estatisticamente (p<0,05) dos demais grupos, com exceção ao grupo de 0,5mm em relação ao Grupo esmalte quando analisado o cimento dual convencional (p>0,05). Concluiu-se que quanto menor a espessura da restauração, maior a alteração de cor e de luminosidade do cimento dual convencional. As alterações do cimento autoadesivo não dependem da espessura da restauração. / The aim of this study was to evaluate the color stability of resin cements for luting ceramic restorations with different thicknesses submitted to accelerated artificial aging (AAA). Sixty sound human molars had their root portions embedded in PVC rings (15-mm diameter) with acrylic resin. Their occlusal surfaces were flattened according two substrates: 30 surfaces until enamel and 30 until dentin. Then, 10 teeth of each substrate were considered as control groups for restored teeth. Forty specimens of ceramic (IPS e-max Ceram, Ivoclar Vivadent) were obtained with two different thicknesses (0.5 mm and 1.0 mm) and were randomly separated into two groups (n = 10) according to the type of the Dual resin cement used for luting: conventional (Variolink II, Ivoclar / Vivadent) or self-adhesive (Rely-X Unicem, 3M ESPE). Also, 10 specimens (0.5 mm) of each cement were obtained to be considered as control groups for materials. All specimens were stored at 37º C for 24 hours, and initial color readings (Vita Easyshade, VITA) were performed. Then, they were submitted to AAA for 580 hours, and final color readings were taken. Color stability and brightness were evaluated. Data of color stability (&Delta;E) and brightness (&Delta;L) were statistically analyzed (2- way ANOVA, Bonferroni, p<0.05) and the comparison of materials with control groups was performed using one-way ANOVA and Tukeys test (p<0.05). The conventional dual cement showed the greatest change in color and brightness when under restorations of 0.5 mm, statistically different (p<0.05) to restorations of 1.0 mm. There was no statistically significant difference (p>0.05) when comparing materials. When analyzing the color stability and brightness of restorations groups compared to control groups, both cements showed greater changes, statistically different (p<0.05), than other groups, except for the group of 0.5 mm in relation to enamel group when the dual conventional cement was analyzed (p>0.05). It was concluded that the smaller the thickness of the restoration, the greater the color and brightness changes of the dual conventional cement. Changes of the self-adhesive cement do not depend on the thickness of the restoration.