Hybrid composites were introduced in the 1980s and are more commonly known as resin-modified glass ionomer cements (RMGICs). The material consists of a powder containing a radio-opaque fluoroaluminosilicate glass and a photoactive liquid contained in a dark bottle or capsule. The material was introduced, as resin composites on their own were not suitable for Class II cavities. RMGICs can be used instead. This mixture or resin and glass ionomer allows the material to be set by light activation (resin), allowing a longer working time. It also has the benefit of the glass ionomer component releasing fluoride and has superior adhesive properties. RMGICs are now recommended over traditional GICs for basing cavities. There is a great difference between the early and new hybrid composites.