Comparison of capsule-mixed versus hand-mixed glass ionomer cements Part 1: compressive strength and surface hardness

Dental restorative glass ionomer cements (GIC) are available as hand-mixed or capsulated products. Capsulation facilitates uniform ratios of powder to liquid, that should result in an optimal end-product. If this is evident, the degree to which capsulated GIC are mechanically stronger will aid in deciding when to use them instead of the handmixed variety. The compressive strength and surface hardness of handmixed GIC were compared to capsule-mixed equivalents. Eighty samples were manufactured from hand-mixed GIC: Riva Self Cure; Fuji IX GP; Ketac Universal, Ketac Molar Easymix, and equivalent capsule-mixed GIC: Riva Self Cure; Fuji IX GP; Ketac Universal Aplicap and Ketac Molar Aplicap. Compressive fracture strength was tested using a universal testing apparatus. Surface hardness was measured with a Vickers digital micro-hardness tester Significant differences were found between the compressive strength of RSCH and RSCC (P = 0.027), and, between KMH and KMC (P < 0.001). Significant differences in surface hardness were found between FIXH and FIXC (P = 0.031),KUH and KUC (P < 0.001), as well as KMH and KMC (P = 0.006). Three capsulated forms of GIC (RSCC, KUC, KMC) demonstrated superior mechanical properties. Capsulated GIC offer advantages which may translate to clinical application