The aim of this article is to review the development of glass ionomer cements (GICs) over the last 40 years and look critically at both their clinical advantages and disadvantages. Primarily, it will explore the future development of both GICs and related ion-releasing materials in relation to improved mechanical properties, capability to prevent secondary caries and promoting remineralisation of hard carious dentine left after minimal cavity preparation procedures, including atraumatic restorative treatment. This article will also introduce new materials with a focus on degradable fluorine-containing glass fillers, including alkasite glasses and fluorine-containing bioactive glasses, that have the capability to raise the pH and promote remineralisation with the potential for fluorapatite formation.