Clinical evaluation of two dental bleaching techniques

To clinically evaluate the bleaching effect, tooth sensitivity and rebound effect (3-month follow-up) of combined bleaching technique and deep bleaching technique.

30 Patients were recruited according to inclusion and exclusion criteria. Both two dental bleaching techniques, included in-office bleaching followed by at-home bleaching, and at-home bleaching followed by in-office bleaching and at-home bleaching, which were called combined bleaching technique and deep bleaching technique, respectively, were performed in the same mouth in each subject. All subjects received at-home bleaching with 6% hydrogen peroxide (HP) for 1 h/d within 7 days on one side of the dental arch (15 on the left side and the other on the right side), and followed by three 8-minute in-office bleaching treatments in succession with 35% HP on the maxillary anterior teeth, and finally with identical at-home bleaching on the maxillary anterior teeth. Tooth color was objectively evaluated using Olympus Crystaleye Spectrophotometer at the baseline appointment, and 1^st, 7^th, 30^th and 90^th day after treatment. The soft tissues and sensitivity of gingival and hard tooth tissues were evaluated using Loe and Silness Gingival Index and Visual Analog Scale (VAS) at baseline, 1^st and 7^th day after treatment.

Significantly less prominent color change and tooth sensitivity were observed in teeth received combined bleaching technique, compared with those received deep bleaching technique (P < 0.05). There was no significant difference in color rebound effect between the two bleaching techniques (P > 0.05).

Both combined bleaching technique and deep bleaching technique show satisfactory effects and the same rebound effect during the same periods of follow-up. Deep bleaching technique is a more effective method of bleaching, however, with high frequency of tooth sensitivity.