EDAB proved to be more reactive than DMAEMA, being less influenced by DPI. Resins containing a 1:2 CQ/amine ratio had better properties than those with 1:1.
Objectives:The aim of this study was to evaluate the effects of different light sources and curing time on the degree of conversion and microhardness of two surfaces within a nanofilled composite resin.Methods:Four experimental groups (n=10) were formed in accordance with the light source (quartz-tungsten halogen (QTH – 600mW/cm2), or light-emitting-diode (LED - 800mW/cm2)) and the time of curing (20 s or 40 s). The specimens were prepared with a circular mould (5 mm ∅ and 2 mm thick), according to the respective protocol, and the Knoop microhardness and degree of conversion was measured at the top and the base of the specimens. The degree of conversion was evaluated by the Fourier transform infrared spectrometer (FTIR). The results were analyzed by ANOVA two-way repeated measures and Tukey’s test (α=,05).Results:Both the degree of conversion and microhardness were higher at the top than at the bottom of the specimens. The QTH light source presented better values on the degree of conversion evaluation, but this result was not observed in the microhardness evaluation. Although forty seconds of curing promotes an increased level of microhardness, it did not influence the degree of conversion.Conclusion:It could be concluded that increasing the time of curing to 40 s promotes an increase in microhardness, but it does not influence the degree of conversion of a nanofilled composite resin. QTH promote better monomeric conversion; however, the microhardness values are similar to LED curing. For all situations tested, the bottom of the specimens presented lower results than the top.
Aim: The yellowing effect is undesirable and can occur in the dental restoration margins when light-cured resin cements containing camphorquinone as photoinitiator is used. This study aimed to evaluate the effect of diphenyliodonium hexafluorphosphate (DPI) in photoinitiator systems that contained different concentrations of camphorquinone (CQ) and dimethylamino ethyl benzoate (EDAB) on resin cements. Methods: A base (1:1) of bisphenol A diglycidyl methacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) was obtained, and 60wt% of glass fillers was added. Eight formulations were obtained: RC1 (0.5mol% CQ / 1mol% EDAB), RC2 (0.5mol% CQ / 2mol% EDAB), RC3 (1mol% CQ / 1mol% EDAB), RC4 (1mol% CQ / 2mol% EDAB), and RC5 to RC8, which contained the same bases plus 0.5mol% DPI. Experimental resin cements were evaluated by the degree of conversion (DC), L*a*b* color analysis, water sorption (WS) and solubility (S), flexural strength, and Elastic Modulus. The data were analyzed by three-way ANOVA, Tukey’s and Mann-Whitney tests (α = 0.05). Results: The combination of DPI and 0.5mol% CQ increased DC in RC6 and L* in RC5 without increasing the WS and a* b* values. CQ at 1mol% showed higher values of b* and lower values of a*, except for RC3. Groups with 2mol% EDAB showed higher DC. Conclusion: The addition of DPI reduces CQ, generating a decreased yellowing effect, while maintaining adequate properties in the resin cements, especially with 2mol% EDAB.
The aim of this study was to evaluate the effect of the addition of the Diphenyliodonium Hexafluorophosphate (DPI) on the properties of experimental lightcured resin cements and its influence on the color analysis. To the monomers base composition (1:1 mass ratio) Bisphenol A Diglycidyl Methacrylate (BisGMA) and Triethylene Glycol Dimethacrylate (TEGDMA) 0.1mol% Butylated Hydroxytoluene (BHT) was added as an inhibior. Camphorquinone (CQ) and Dimethylamino Ethyl Benzoate (EDAB) were added at 2 different concentrations with or without the addition of 0.5mol% DPI, resulting in eight groups: RC1 (0.5mol% CQ / EDAB1mol% without salt) , RC2 (0.5mol% CQ / 2mol% EDAB without salt), RC3 (1mol% CQ / 1mol% EDAB without salt), RC4 (1mol% CQ / 2mol% EDAB without salt), RC5 (0.5mol% CQ / 1mol% EDAB with salt), RC6 (0.5mol% CQ / 2mol% EDAB with salt), RC7 (1mol% CQ / 1mol% EDAB with salt), RC8 (1mol% CQ / 2mol% EDAB with salt). After the manipulation of the resinous matrix, 60wt% of silanated bariumaluminum-silicate glass was added as a filler. The studied properties were the following: Degree of Conversion (DC) (n=5) by Fourier transformed infrared spectrometer; L*a*b* Color Analysis (Y) by reflectance spectrophotometer with CIELab system; Sorption (WS) and Solubility (S) in distilled water (n=5); Flexural Strength (FS) and Modulus of elasticity (E) (n=10). Statistical analysis (α=0.05) was performed for each test separately by ANOVA three way and Tukey's test. MannWhitney were used for color analysis (L* variable). The results showed that the addition of the DPI increased the degree of conversion and L* without increasing the sorption and the values of a*b* in cements containing 0.5mol% CQ. 1mol% CQ concentration showed higher values of b* and the lower sorption without salt. Groups with EDAB 2mol% showed a higher DC. S, FS and E showed no statistical differences. It can be concluded that the addition of the DPI allows the reduction of the CQ with a lower yellowing effect, maintaining adequate properties in the experimental cements tested.
DEDICATÓRIAA Deus, pela vida, pela família, pelos amigos. Obrigada senhor por tudo o que me destes. Sempre sinto Tua presença em tudo o que faço, por todos os lugares que ando. Somente em Ti posso ter total confiança, descansar minhas preocupações, recarregar a minha alma, fortalecer minha mente. Somente Tu conheces os mais profundos desejos do meu coração e confio plenamente que Teus planos são feitos especialmente para a minha felicidade. Obrigada pelos dias em que até mesmo o Teu silêncio me fez ver o quanto eu sou feliz, o quanto eu sou abençoada e o quanto eu venci. Ao meu pai Wellington, por tudo. Pela vida, pelo amor, pela educação e disciplina. Obrigada por ter sido um paizão, por ter brincado comigo e por ter feito questão de que eu tivesse uma infância muito feliz. Nunca vou me esquecer de como o senhor me ensinava as tarefas da escola, sempre com muita preocupação com meus estudos. Obrigada por ter me levado ao consultório quando eu era pequena, de ter tido paciência de me explicar tudo o que eu perguntava sobre a odontologia e sobre a vida. Fico feliz em poder ter seguido a sua profissão e principalmente de ser feliz exercendo a odontologia assim como o senhor é. Obrigada por me ensinar a vencer, dando seus exemplos diários de trabalho, esforço e dedicação. À minha mãe Ângela, por tudo. Pela vida, pelo amor, pelos ensinamentos e pelos cuidados que teve comigo. Obrigada pelo incentivo desde a iniciação científica e pela torcida por esse trabalho, mesmo sem compreender muito bem o significado dele. Aos meus irmãos Cristiane, Paulo e Davi pelos muitos momentos de alegria e brincadeiras, sempre me fazendo rir. Apesar da distância, sempre tenho vocês nos meus pensamentos e orações diárias. Obrigada por terem entendido a minha ausência e pela torcida. Amo vocês! v AGRADECIMENTOS ESPECIAIS Ao Professor Doutor Fabio Hiroyuki Ogata Mitsui da Universidade do Estado do Amazonas. Agradeço muito a confiança que o senhor sempre depositou em mim, acreditando no meu trabalho clínico e científico. Se quando criança eu quis ser dentista quando crescesse pelos exemplos do meu pai, o motivo de eu ter feito este mestrado foi porque eu quis um dia ser igual ao senhor também. O senhor sempre será um exemplo de professor, orientador e educador. Espero um dia fazer por meus alunos o que o senhor teve a grandeza de fazer por mim: dar oportunidade e acreditar. Meus sinceros agradecimentos! À minha orientadora Professora Doutora Giselle Maria Marchi Baron. Quando eu decidi fazer mestrado, senti o medo de ter que sair de casa e sabia das responsabilidades que viriam pela frente. Eu só não sabia que seria tão agradável passar por tudo isso sendo orientada pela senhora. Além dos exemplos do meu pai e do Professor Fabio, tenha certeza de que muitas das suas atitudes serão copiadas por mim. A senhora é um exemplo não só de uma ótima profissional, mas também de uma pessoa humana, que respeita o próximo e zela pelos valores que nós realmente levamos dessa vida. Obrigada por sempre ter dado apoio quando necessário, por ter acreditado ne...
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