Natural teeth are made of various kinds of tissue, which strongly differ aesthetically and optically. Dentine, for instance, is duller when compared to enamel. It is therefore clearly difficult to restore the original optical properties of a tooth using only one material when the cavity preparation involves both dentine and enamel.
The shade selection should be done under natural daylight before placing the rubber dam, keeping in mind that not only the tooth to be restored but also the adjacent ones have to be observed. The dentine shade should be selected based on the mid and cervical thirds of the tooth of concern. At the end, the level of translucence should be defined.