Preparation by sol-gel method and evaluation of lanthanum-containing filling glass ionomer cement powder

• A novel filling glass ionomer cement powder containing lanthanum was prepared successfully via the Sol-gel method.
• The relations between mechanical strength and the different amount of lanthanum substitution for calcium of GIC powders were studied.
• Lanthanum-containing filling GIC could improve the GIC's mechanical strength effectively.

To improve the mechanical properties of filling glass ionomer cements (GICs), lanthanum substitution for calcium in glass composition was investigated based on formula 2.3SiO2−2.2Al2O3−0.5CaO-0.5CaF2−0.08P2O5 (BF). Compared with the commercial GIC, a series of lanthanum-containing glass powders were prepared via Sol-gel method. Compressive strength and Vickers hardness of experimental GICs were tested. XRD, SEM and EDAX were used to evaluate GIC powders and samples. In vitro biocompatibility was evaluated by methyl-tetrazolium (MTT) assay as well as the net setting time was tested. Incorporation of lanthanum in the glass powder could significantly improve GIC's mechanical properties. The all-lanthanum substitution (1La) GIC showed the highest Compressive strength (146.25 MPa), 47.7% and 41.98% higher than commercial and 0La (BF) group, and Vickers hardness (49.25 MPa), 39.2% and 28.02% higher (P<0.05), which was possibly due to the new stronger glass network forming, and leading to the improvement of curing reaction.1La and 0La GICs showed fine biocompatibility in initial cultivation stage. The net setting time of experimental GICs met the clinical requirements. The results demonstrated that lanthanum-containing filling GIC powder could be prepared successfully by Sol-gel method as well as could improve the GIC's mechanical strength effectively.