Fig. 1.

Initial appearance of the non-carious cervical lesions to be evaluated (A). Two impressions of the tooth to be restored (B and F). Window created, using a circular metallic device, in the cervical third (C and G). Window created, in the middle third (D and H). The spectrophotometer tip inserted into the holes of the silicone guide, in the cervical third (E). The spectrophotometer tip inserted into the holes of the silicone guide, in the middle third (I)