Abstract
In recent years, composite resins and the respective bonding systems play the main roles in aesthetic restorative material. However, we will not be able to disregard glass ionomer cement which has the longer history as an adhesive restorative material than composite resin. Unlike composite resin, glass ionomer cement has an ability to adhere to unconditioned tooth structure in its original meaning. However, glass ionomer cement has both advantages and disadvantages as its being a cement. And the knowledge of the history and improvement of glass ionomer cement is important for the better understanding of composite resin.
Glass ionomer cement was developed as an aesthetic restorative material which adheres to tooth structure in its original meaning. Multitudinous researches of glass ionomer cement disclosed its advantages and disadvantages, so that the application of glass ionomer cement shifted from restorative material (enamel substitute) to lining and base material (dentin substitute) and luting material. Although glass ionomer cement has a lot of advantages, still it involves several disadvantages. Resin-modified glass ionomer cement was introduced to solve those disadvantages. Further improvement of resin -modified glass ionomer cement will continue to be performed. However, compared to the resin-modified glass ionomer cement, the conventional glass ionomer cement has its own superiority such as low shrinkage rate during hardening, and further improvement of the conventional glass ionomer cement is also expected.
