Objective: To evaluate water sorption, solubility and hygroscopic expansion and the effect of desiccation for a calcium silicate-based material, a conventional glass ionomer, and a resin-modified glass ionomer.
Methods: Water sorption, solubility and hygroscopic expansion of Biodentine™ (BD), GC Fuji IX GP® FAST (FJ), and Ionolux (IO) were tested under two pre-storage conditions: with desiccation and without desiccation. Disc-shaped samples (n=5) were immersed in water and weighed at different time intervals (1h, 24h, 3d, 7d and 30d) and hygroscopic expansion was recorded at 7d and 30d. Data were analysed using Factorial repeated measures ANOVA, one-way/two-way ANOVA, Independent samples t-test and Tukey's post hoc test (α=0.05).
Results: With desiccation, sorption of IO and FJ was 124.33μg/mm3 and 79.97μg/mm3 respectively. Solubility was -12.36μg/mm3 for IO and -20.19μg/mm3 for FJ. Hygroscopic expansion was 3.01% for IO and -2.35% for FJ. Without desiccation, sorption was in the order: IO˃BD˃FJ (130.35μg/mm3, 122.07μg/mm3, and 107.21μg/mm3 respectively), while solubility order was: BD˃FJ˃IO (154.83μg/mm3, 88.82μg/mm3, and 25.67μg/mm3 respectively). IO and FJ showed significant difference in sorption and solubility between the two pre-storage treatment groups (p˂0.005). Hygroscopic expansion was in the order: IO˃BD˃FJ.
Significance: BD had the highest solubility while IO had the least. The relatively stable polymeric resin in IO may contribute to its low solubility but high hygroscopic expansion. Desiccation had significant effect on sorption, solubility and volumetric expansion of water-based materials.
Keywords: Dentine replacement; Desiccation; Hygroscopic expansion; Solubility; Sorption.
Copyright © 2018. Published by Elsevier Inc.