Evaluation of the relationship between the cost and properties of glass ionomer cements indicated for atraumatic restorative treatment.

The aim of this study was to evaluate microshear bond strength (muSBS), water sorption and solubility of glass ionomer cements (GIC) indicated for atraumatic restorative treatment (ART). Cylindrical specimens (6 x 2.4 mm) were used to test the sorption and solubility of each GIC (n = 5). The specimens were weighed before and after immersion in water and desiccation. For the muSBS test, 60 primary molars were ground to obtain flat surfaces from both enamel and dentin. The teeth were then assigned to the tested GIC (n = 10) groups, namely Fuji IX - FIX, Ketac Molar - KM and Maxxion R - MX. The exposed surfaces were pre-treated with GIC liquid. Polyethylene tubes were placed on the pre-treated surface and filled with one of the GIC. After 24 h, the specimens were submitted to the muSBS test. The failure mode was assessed using a stereomicroscope (400 x magnification). The powder to liquid ratio and cost of material were also determined (n = 3). The data were analyzed by ANOVA and Tukey's post hoc test. Linear regression was used to determine the relation between cost and the other variables. Overall, MX showed lower muSBS values (enamel: 3.93 +/- 0.38; dentin: 5.04 +/- 0.70) than FIX (enamel: 5.95 +/- 0.85; dentin: 7.01 +/- 1.06) and KM (enamel: 5.91 +/- 0.78; dentin: 6.88 +/- 1.35), as well as higher sorption and solubility. The regression analyses showed a significant and positive correlation between cost and muSBS in enamel (R2 = 0.62; p < 0.001) and dentin (R2 = 0.43; p < 0.001); and a negative correlation between cost and water sorption (R2 = 0.93; p < 0.001) and solubility (R2 = 0.79; p < 0.001). In conclusion, the materials indicated for ART exhibit distinct physical and mechanical properties; in addition, low-priced materials may interfere with GIC properties.