“…The matrix was perforated with the aid of a 6 mm diameter circular scalpel (Biopsy Punch, Miltex, York, Pennsylvania, USA), similar to the active tip of the Vita Easyshade spectrophotometer, in the vestibular region, in the middle third, of the right and left maxillary. 2,8,17,24,30 The difference between the colors was recorded before the bleaching procedure, weekly for 2 weeks, 1 month, and 12 months after the end of the treatment. They were calculated using the following CIELab formula 31 :…”