Compressive strength of different conventional glass ionomer cements: an in vitro analysis

Abstract

Objective: To evaluate, through an in vitro study, the compressive strength of different brands of conventional glass ionomer cements (GICs) at different time intervals. Methodology: Six commercial brands of conventional GICs were assessed according to a 6 × 3 factorial design (material × time). Eight cylindrical specimens were fabricated for each experimental group. The specimens were evaluated at T1 (immediate setting), T2 (24 hours), and T3 (6 months), and stored in distilled water at 37 °C for the corresponding periods. The diametral compressive strength test was performed using a universal testing machine (Instron®, Norwood, MA, USA) at a crosshead speed of 0.5 mm/min until fracture. Data were analyzed using ANOVA followed by Tukey’s post hoc test (α = 0.05). Results: At T1 (immediate setting), the six GIC groups exhibited statistically similar performance. At T2 (24 hours), a significant difference among materials was observed, with Riva Self Cure (SDI®) showing higher strength values. At T3 (6 months), Bioglass (Biodinâmica®) demonstrated superior results. Conclusion: The findings demonstrate variations in the mechanical behavior of GICs over time, reinforcing the importance of further studies evaluating different surface protection methods and their influence on the mechanical properties of the material.