Influence of bioactive particles and onium salt on the physicochemical properties of experimental infiltrants

Abstract This study evaluated physicochemical properties of experimental infiltrants after addition of hydroxyapatite nanoparticles (HAp) or 58S bioactive glass (BAG) and diphenyliodonium hexafluorophosphate (DPI). The resin matrix was composed of TEGDMA/Bis-EMA (3:1), 0.5 mol% CQ, and 1 mol% EDAB. The blends received or not 0.5 mol% DPI and 10% wt BAG or HAp. Icon was used as commercial control. The groups were characterized by XRD, FT-IR spectrometry, and SEM before and after simulated body fluid (SBF) immersion for up to 7 days. Polymerization kinetics (n =3 ), water sorption and solubility (n=10), and viscosity (n = 3) were surveyed. For polymerization kinetics, the samples were polymerized for 5 min and the data were obtained from 40 s and 5 min. Statistical analysis was made using ANOVA and Tukey's test (a = 0.05). After 7 days of SBF immersion, XRD and FT-IR showed that the HAp crystalline phase was present only in the HAp groups. A lower degree of conversion (DC) and polymerization rate were observed for the Icon and BAG groups, whereas HAp showed higher values. For the BAG group, DPI increased polymerization rate and DC in 40 s. After 5 min, all groups presented DC above 80%. In groups with particles, the HAp groups exhibited higher viscosity, whereas DPI groups showed a decrease in viscosity. Icon had the highest water sorption. To conclude, BAG neither improved the physicochemical properties studied, nor did it show bioactive properties. The addition of DPI reduced viscosity caused by particle addition and also attenuated the DC decrease caused by BAG addition. The addition of bioactive particles to infiltrants should be seen with caution because they increase viscosity and may not bring major clinical improvements that justify their use. DPI might be indicated only if any component is added to the infiltrant to act as a compensation mechanism

Influence of barium and zirconium oxide incorporation in the physicochemical properties of experimental and commercial infiltrants

Orientador: Giselle Maria Marchi BaronDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo deste estudo foi avaliar a influência da adição de diferentes concentrações de partículas de carga (óxido de bário 25/45% em peso ou de óxido de zircônia 25/45% em peso) em um infiltrante comercialmente disponível (Icon®, DMG, Alemanha) e de um infiltrante experimental nas propriedades de resistência coesiva (RC), grau de conversão (GC), sorção (So) e solubilidade (Sol), radiopacidade e profundidade de penetração. Para avaliar a RC (n=10) foi utilizado teste de microtração em máquina de ensaios universais. Para a avaliação do GC (n=5), mensurações antes e após fotoativação das amostras foram realizadas em espectrômetro infravermelho com transformador de Fourier (FTIR). Para os testes de So e Sol (n=10), após dissecação, as amostras polimerizadas foram pesadas, armazenadas em água destilada por 7 dias e pesadas novamente, após nova secagem, até obtenção da massa final. Para análise da radiopacidade (n=5) os corpos de prova foram fotoativados e armazenados em estufa e a análise da radiopacidade foi realizada utilizando o sistema de radiografia digital e foram comparadas pela escala de cinza e avaliadas pelo histograma no software Adobe Photoshop®. Para profundidade de penetração foram utilizados blocos de esmalte de molares humanos (n=50), submetidos à simulação de lesão inicial cariosa em solução desmineralizante (DES). Posteriormente, os blocos foram infiltrados pelos infiltrantes e submetidos à análise da profundidade de penetração (n=5) por meio da microscopia confocal de varredura a laser. As análises foram realizadas no programa R, com nível de significância de 5%, com exceção da análise de profundidade de penetração, que foi somente avaliada qualitativamente. Para RC, independentemente do infiltrante, os grupos com adição de 45% de zircônia tiveram valores maiores. Entre os grupos sem adição de partículas (controle), o infiltrante experimental apresentou maior GC que o Icon®. Já para os grupos com adição de bário e com adição de 25% de zircônia o Icon® apresentou maior GC. O infiltrante experimental apresentou menor So que o Icon®, independentemente da concentração das partículas. Radiopacidade maior que o esmalte foi observada somente nos grupos com Zircônia 45%. Todos os grupos obtiveram profundidade de penetração similares, porém os grupos contendo o infiltrante experimental parecem ter tido prolongamentos de tags mais longos. Concluiu-se que a adição de 45% de partículas de Zircônia aumentou a RC e promoveu radiopacidade maior do que a do esmalte. Aumento do GC foi observado no infiltrante experimental sem partículas quando comparado ao Icon®. Menor So foi encontrada para os grupos com infiltrante experimental. Todos os grupos tiveram Sol abaixo do recomendadoAbstract: The aim of this study was to evaluate the influence of the addition of different concentrations of particles (barium oxide 25/45% or zirconium oxide 25/45% by weight) in a commercially available infiltrant (Icon®, DMG, Germany) and experimental infiltrant on cohesive strength, degree of conversion, sorption and solubility, radiopacity and penetration depth. In order to evaluate the cohesive strength (n=10) microtensile was performed with an universal test machine. For the degree of conversion evaluation (n=5), measurements before and after photoactivation of the samples were performed in a Fourier transform infrared spectrometer (FTIR). For sorption and solubility tests (n=10), after dissecting, the polymerized samples were weighed, stored in distilled water for 7 days and weighed again, after re-drying, until the final mass was obtained. For radiopacity (n = 5) analysis, the specimens were photoactivated and stored in an oven and radiopacity analysis were performed using the digital radiography system. To evaluate and compare the level of radiopacity, samples were compared by the grayscale and evaluated by the histogram in AdobePhotoshop® software. For penetration depth, enamel blocks of human molars (n = 50) were used, which were submitted to simulation of carious initial lesion in demineralizing solution (DES). Subsequently, the blocks were infiltrated by the Infiltrants Icon® and experimental and submitted to depth penetration analysis (n = 5) by confocal laser scanning microscopy. Analyzes were performed in program R, with a significance level of 5%, except for penetration depth analyzes, which was only evaluated qualitatively. For cohesive strength, regardless of the infiltrating, the groups with 45% zirconia incorporation showed greater values. Among the groups without addition of particles (control), the experimental infiltrant presented higher degree of conversion than Icon®. For the groups with addition of barium and 25% of zirconia, Icon® presented higher degree of conversion. The experimental infiltrate presented lower sorption than Icon®, independently of the concentration of the particles. Greater radiopacity than enamel was observed only in the groups with 45% Zirconia. All groups obtained similar penetration depth, but the groups containing the experimental infiltrant appear to have had longer tag extensions. It was concluded that the addition of 45% of Zirconia particles increased cohesive strength and obtained radiopacity higher than that of enamel. An increase in degree of conversion was found in the experimental infiltrant free of particles when compared to Icon®. Minor sorption was found for groups with experimental infiltrating. All groups had solubility below recommendedMestradoDentísticaMestra em Clínica Odontológica2017/14378-6FAPES