Glass ionomers apparently play a useful part in restorative dentistry. In addition to its excellent properties it provides sufficient scope for modification and improvement. Glass ionomer cements are very aptly referred to as "Man made dentin" as well as "dentin substitute". It is more than fifty years since the introduction of the glass ionomer cement family to the dental profession. After a slow start on the way they can now be regarded as well understood and thoroughly researched materials with very wide applications.