Effect of low concentration calcium silicate-based additive (MTA) on the compressive strength of glass ionomer cement at various time intervals: An <i>in vitro</i> pilot study

Objectives: To evaluate the effect of incorporating a low concentration of mineral trioxide aggregate (MTA) into conventional glass ionomer cement (GIC) on its compressive strength after immersion in artificial saliva at different time intervals. Material and Methods: Twenty cylindrical specimens, each about 5 mm in diameter and 8 mm in height, were created with standardized molds. These were split into two groups: Group I (control), GIC, and Group II (experimental), GIC reinforced with 5% mineral trioxide aggregate by weight. The specimens were submerged in artificial saliva and kept under controlled lab conditions. Compressive strength was tested after 1 and 7 days using a universal testing machine at a crosshead speed of 1 mm/min. Data were then statistically analyzed. The Mann–Whitney U test compared groups, while the Wilcoxon Signed Ranks test compared within-group differences. A p- value below 0.05 indicated statistical significance. Results: The GIC + MTA group showed a higher mean compressive strength than the conventional GIC group at both points. A highly significant difference was found at 1 day ( p &lt; 0.01). By 7 days, the difference was no longer statistically significant ( p &gt; 0.05). Within the GIC + MTA group, compressive strength increased significantly from 1 day to 7 days ( p &lt; 0.05), with peak strength observed at 1 day. However, at 7 days, the difference between the groups was not statistically significant ( p= 0.117). GIC + MTA showed the highest early strength at 1 day, but decreased at day 7. Conclusion: Within the limitations of this in vitro study, the incorporation of 5% MTA into conventional GIC improved the material's early compressive strength. However, the difference in compressive strength between the modified and conventional materials was not significant at 7 days. Further studies are recommended to evaluate the long-term mechanical properties and clinical performance of GIC modified with MTA.