Is the at-home bleaching treatment applied only on the lingual surface as effective as that on the buccal surface? A randomized clinical trial

This double-blind randomized clinical trial compared the effectiveness and bleaching sensitivity (BS) of at-home dental bleaching performed on the buccal surface and on the lingual surface. Using a split-mouth design, 25 patients were assigned to two bleaching groups: 10% hydrogen peroxide (White Class 10%, FGM) applied once daily for 60 min to the buccal surface (BSB) and 10% hydrogen peroxide (White Class 10%, FGM) applied once daily for 60 min to the lingual surface (LSB), both for 14 days. The color was evaluated before bleaching, after the first and second weeks, and 1 month after the bleaching using Vita Classical and Vita Bleachedguide scales and a Vita Easyshade spectrophotometer. BS was recorded daily using a 0–4 numerical rating scale and a 0–10 visual analogue scale. The following statistical tests were used: color changes (Mann–Whitney), absolute risk of BS (McNemar’s exact), and the intensity of BS (Mann–Whitney). In all statistical tests, the significance level was 5%. Significant bleaching was observed after the end of bleaching in both groups, with higher bleaching effectiveness for BSB when compared to LSB (p