Development of experimental resin modified glass ionomer cements (RMGICs) with reduced water uptake and dimensional change

Objective. To investigate water uptake, desorption, diffusion coefficient, solubility and dimensional changes of four experimental RMGICs in deionized water (DW) and artificial saliva (AS), and compare with two commercial RMGICs and control home liquids based on the two commercial materials used. Methods. Two commercial RMGICs, RelyX Luting (RX, 3M ESPE) and Fuji Plus (FP, GC), two control home liquids and four new liquid compositions (F1, F2, R1, R2) comprising different percentages of the monomer THFM (tetrahydrofurfuryl-methacrylate) with the original monomer HEMA (2-hydroxyethyl-methacrylate) were used in this study. Home and experimental liquids were mixed with the corresponding commercial powder. Disk-shaped specimens (16 mm diameter 1 mm thickness) were immersed in DW/AS at 37 degrees C (n = 6) and weighed at regular time intervals. Percentage weight change with time was recorded. At 24 weeks, disks were desorbed in an oven at 37 degrees C to minimum weight. Results. All new compositions showed lower water uptake and dimensional (volume) changes than the commercial products in both DW and AS. On desorption, FP showed higher weight loss compared to materials in the same group in both solutions (p < 0.0001), with the exception of F2 in DW (p = 0.283). RX had higher weight loss compared to R1 and R2 in DW and AS (p < 0.0001). Fickian diffusion was confirmed for all materials immersed in DW and AS. Significance. The experimental compositions in this study have shown promising results when tested in both DW and AS with lower water uptakes and volume changes than commercial materials. This may lead to wider applications than current commercial materials. (C) 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.