In vitro investigation of the roughness, water absorption and water solubility of resin containing restorative materials

Objective: This study was aimed to evaluate on water sorption, solubility and surface roughness of resin based restorative Method: In this study, a Bulk-fill (Filtek Bulk Fill Posterior Restorative), microhybrid (Charisma® Smart), a nanohybrid indirect resin composites (GradiaTM Plus indirect composite) and a light cure resin modified glass ionomer cement (RIVA resin modified glass ionomer cement) were used and 80 samples of 4 mm diameter and 4 mm thickness were prepared. To determine the water sorption and solubility values, the initial weights of the samples were noted in micrograms (μg) (M1). The initial surface roughness (SR) of all samples was measured with a profilometer (Surftest SJ-201, Mitutoyo, Tokyo, Japan) and was expressed in μm as Ra1. The samples (n=10) were immersed into 2 different solutions (distilled water, citric acid) for 40 days, then the weights of the samples after standing in the solutions were noted in micrograms (μg) (M2). Repeated SR measurements were performed at 40 days storage time (Ra2). Thereafter, the specimens were stored in the desiccator and reweighed until a constant dry mass (M3) was attained. Water sorbtion and solubility (μg/mm3) were calculated based on ISO 4049:2009 standards. Statistical analysis was performed using the One-way ANOVA and Tukey HSD multiple comparisons (p=0.05). Results: CIS groups showed higher surface roughness and water absorption values than composite groups (p<0.05). It was found that there were significant differences between the groups in terms of water solubility (p<0.05). CIS-SA group showed the highest water solubility value and this solubility value was statistically different from all other groups. Conclusion: Among the tested groups in storage medium, only the glass ionomer cement group showed a significant increase in surface roughness, water absorption and solubility. The greatest change in water absorption, solubility and surface roughness was observed in the CIS-SA group. The waiting environment did not make any difference between the composite resin groups in terms of water absorption and surface roughness change. The storage medium did not cause a significant difference in the solubility of the composites between the composite groups. Key words: water solubility, sorption, surface roughness, citric acid.