CoForm, matrix system, is a unique set of pre-formed transparent matrices, made of celluloid plastic that are specifically designed to deal with composite Class IV restorations as well as various tooth fractures. The method and advantages of celluloid plastic matrices.The cavity is filled in layers in the usual manner. The only difference is that when the last layer is placed, instead of shaping and curing, the matrix is pressed onto the uncured composite giving the restoration the anatomy of a healthy tooth. The composite is then cured through the clear matrix.