Mechanical properties and water sorption of two experimental glass ionomer cements with hydroxyapatite or calcium fluorapatite formulation.

In this study the mechanical behavior and water sorption (Ws) of experimental glass-ionomer-cements (GICs) with hydroxyapatite (HA) or calcium fluorapatite (CFA) prototype formulations were examined. Specimens from two experimental and one commercially available GIC were prepared in three protocols; (1) according to the manufacturer's instructions, (2) with coating and (3) with heat application. The specimens were stored in distilled water or artificial saliva at 37°C for 7- and 30-days. Flexural strength (FS), Vickers hardness (VHN) and Ws of GICs were evaluated. Experimental GICs showed higher FS values than commercial GIC (p<0.001). Higher FS and VHN values were observed when GICs were prepared according to manufacturer's recommendation. FS was affected only by GIC-type (η=0.027), whereas VHN was affected by GIC-type (η=0.331), treatment-protocols (η=0.067), storage-medium (η=0.100) and increased storage-duration (η=0.317). The tested parameters did not significantly influence the Ws of all tested GICs (p>0.05). The GICs with HA or CFA formulations might represent a promising approach due to their FS, VHN and Ws characteristics.