Composite resin stratification

The colour of natural teeth is determined by the dentine. The enamel acts as a filter and modulates the dentine shade, thereby enhancing the aesthetics of the tooth in most cases. The colour of natural teeth is therefore developed from within the tooth. With composite restorations, however, the dentist normally uses coloured composite enamel materials. The colour effect of the tooth is determined to a very large extent by these coloured enamel materials, with the colour being developed from the outside to the inside of the tooth which is the exact opposite to how colour is developed naturally. The traditional layering technique used in composite restorations adopts this approach. The composite enamel materials may be divided into coloured, modulating and translucent material for incisal edges. The coloured enamel materials form the final layer which ultimately determines the shade of the restoration. Modulating enamel materials, which do not however change the shade, are then applied to the coloured enamel material to enhance the final depth and translucency of the restoration. In an alternative layering technique the colouring is developed outwards from within as with natural teeth. In this case, dentine composites with saturated shades can be used because they are covered and modified by an additional layer of modulating enamel material which enhances the aesthetic value of the restoration in the same way as with natural teeth. With both techniques it must be ensured that these modulating enamel materials are applied in thin layers. As a final procedure, which is mainly carried out on young patients, the translucent incisal edge materials are applied to reproduce the opalescent incisal edge.