Effect of Al2O3 on Microstructure, Thermal, and Physicomechanical Properties, and Biomineralization of Na2O/K2O-CaO-MgO-SiO2-P2O5-CaF2 Glasses for Dental Applications.

Glasses, based on the CaO-MgO-SiO₂ ternary system with Na₂O/K₂O, P₂O₅, CaF₂, and Al₂O₃ additives, were successfully prepared by melting. The effect of alumina addition, low (1.70 wt.% or 1 mol.%), and high (12.50 wt.% or 7-8 mol.%), on glass structure, thermal properties, and their potential use in biomedical applications (bioactivity, machinability), was investigated. The Raman spectra suggest that the Al ions insert into the glass network forming Si-O-Al chains. Hence, the Q³ silicate units decrease, but there is no increase in the Q² units. Liquid–liquid phase separation occurs in the glasses. Alumina doping favors the increase in T_g and T_s, except for the K-containing glasses. The glasses with low alumina content are bioactive in SBF tests, while the glasses with a high amount of alumina are bioinert. Both glasses have a positive value of the machinability parameter, suggesting that both glasses can be shaped by digital milling technology. [ABSTRACT FROM AUTHOR]