Solubility, Sorption and Degree of Conversion of Nanocomposite:Polymerization Mode Influence

Objectives:This study analyzed the relationship between the degree of conversion (DC), solubility, and salivary sorption,comparing a nanofilled resin-composite (Filtek Supreme) and a hybrid (P60) n=10, and evaluated the light-polymerization mode influence on these responses. The two materials which were chosen have the same polymeric matrix, and different types of filler particles. Method:Two light polymerization modes were used: Conventional (C) – 850 mW/cm2 for 20 s, and Gradual (G) - 100 up to 1000 mW/cm2 for 10 s + 1000 mW/cm2 for 10 s. The DC (%) was obtained by FT-Raman spectroscopy. The solubility and salivary sorption were measured after immersion the specimens in artificial saliva for 7 days. Results:The DC of P60 (54.22 ± 3.64) was higher than that obtained by Su. And the C mode presenting the highest DC (55.01 ± 3.15) (p < 0.05) and was influenced by the light polymerization mode: C > G. The solubility of P60 (0.40 ± 0.03 µg/mm3) was lower than that of Su (0.45 ± 0.05 µg/mm3) and the salivary sorption of P60 (6.87 ± 0.31 µg/mm3) < Su (8.04 ± 0.77 µg/mm3, and were influenced by the light polymerization mode: G > C. Conclusions:Correlation was found between DC and solubility (r = - 0.89), and between solubility and salivary sorption (r = 0.95).) The G light polymerization mode produced a lower degree of conversion,and The Nanofilled composite presented higher solubility and salivary sorption than hybrid composite.