Glass ionomer cements are dental materials used for filling cavities and as a base or liner under other restorations. They are made from a mixture of glass particles and an organic acid, which allows them to bond chemically to both tooth structure and metal surfaces. This unique property makes them suitable for various dental applications. One of the key benefits of glass ionomer cements is their ability to release fluoride, which can help prevent further tooth decay. They are also biocompatible, meaning they are safe to use in the mouth, and can be used in both permanent and temporary restorations.