Biological and mechanical properties of an experimental glass-ionomer cement modified by partial replacement of CaO with MgO or ZnO

AbstractSome weaknesses of conventional glass ionomer cement (GIC) as dental materials, for instance the lack of bioactive potential and poor mechanical properties, remain unsolved.Objective The purpose of this study was to investigate the effects of the partial replacement of CaO with MgO or ZnO on the mechanical and biological properties of the experimental glass ionomer cements.Material and Methods Calcium fluoro-alumino-silicate glass was prepared for an experimental glass ionomer cement by melt quenching technique. The glass composition was modified by partial replacement (10 mol%) of CaO with MgO or ZnO. Net setting time, compressive and flexural properties, and in vitrorat dental pulp stem cells (rDPSCs) viability were examined for the prepared GICs and compared to a commercial GIC.Results The experimental GICs set more slowly than the commercial product, but their extended setting times are still within the maximum limit (8 min) specified in ISO 9917-1. Compressive strength of the experimental GIC was not increased by the partial substitution of CaO with either MgO or ZnO, but was comparable to the commercial control. For flexural properties, although there was no significance between the base and the modified glass, all prepared GICs marked a statistically higher flexural strength (p<0.05) and comparable modulus to control. The modified cements showed increased cell viability for rDPSCs.Conclusions The experimental GICs modified with MgO or ZnO can be considered bioactive dental materials.

Study of cell migration by releasing sdf-1 factor from gelatin-siloxane hybrid scaffold / Шинэ санаа Шинэ нээлт

BACKGROUNDScaffolds with the capacity to deliver signaling molecules are attractive for bone regeneration. Here, we developed bioactive siloxane–gelatin hybrid scaffolds via a sol gel process containing stromal derived factor-1 (SDF-1) to recruit osteoprogenitor/stem cells. METHODSThe process was undertaken under room temperature aqueous conditions, which enabled therapeutic molecules to be effectively incorporated. After the sol-gel reaction and lyophilization process, well crosslinked hybrid scaffolds were obtained with porosities of 80–90%.RESULTSDynamic mechanical analysis of the hybrid scaffolds showed significant improvement in storage modulus values (from 10 to 110 kPa) with increasing siloxane content. Target molecule SDF-1 was loaded and released from the scaffolds, and the effects on the homing of mesenchymal stem cell were studied.CONCLUSIONSResults demonstrated significant enhancement in the migration of cells to the SDF-1 loaded scaffolds. Taken together, the developed hybrid scaffolds areconsidered to be useful in loading and delivering signaling molecules such as SDF-1 to recruit osteoprogenitor /mesenchymal stem cells in the bone regeneration process.