Water sorption and solubility of core build-up materials

To investigate the variation in water sorption and solubility across a range of different core build-up materials.

Five materials were tested, four of which are resin-based materials (Grandio Core, Core.X Flow, Bright Flow Core, Speedee) and one resin-modified glass ionomer (Fuji II LC). All specimens (n=10) were immersed in 10ml distilled water in individual glass containers and weighed at one week, 14 and 28 days. After a total immersion time of 28 days, 7 specimens were dried to a constant mass, in a desiccator for 28 days. Three samples of each material were not dried, but were left in distilled water for 1 year, to determine the long-term water sorption properties. Specimens were weighed at monthly intervals until 6 months and then at the 9th and 12th months. Each specimen was measured using a digital electronic caliper (Mitutoyo Corporation, Japan).

After 28 days immersion, the change in water sorption and solubility of the materials ranged from 12.9 to 67.1μg/mm(3) (P<0.001) and 0.9-6.4μg/mm(3) respectively (P<0.001). Except for Fuji II LC, an independent T-test showed significantly higher water sorption and solubility for the other materials after 1-year total immersion in water compared to 1 month (P<0.05). Using repeated measures ANOVA, all materials showed mass changes over time (1 month) (P<0.001).

Grandio Core had the lowest water sorption and solubility among the tested materials. According to the ISO 4049 standards, all the tested materials showed acceptable water sorption and solubility, apart from the water sorption behavior of Fuji II LC.