IN-OFFICE TOOTH BLEACHING WITH 37% CARBAMIDE PEROXIDE

Color evaluation

Objectives: This study will determine the clinical efficacy of bleaching agent 37% carbamide
 peroxide compared to 35% hydrogen peroxide on the change of color scores in anterior superior
 teeth, in-office bleaching technique after 7, 14 and 37 days; and the Risk to the tooth
 sensitivity before, during and 24 hours after the procedure.
 
 Materials and Methods: Fifty patients will be selected for this single-blind, parallel,
 randomized-controlled clinical trial. The whitening treatment with 37% carbamide peroxide or
 35% hydrogen peroxide (control) will be carried out in a single application of 45 minutes for
 two sessions with a 7-day interval. The sensitivity level will be assessed before, during and
 24 hours after the procedure using verbal and analogic visual analogue (VAS) scales. Color
 alteration will be assessed by a bleach guide scale 7 days after each session and 30 days
 after the last session. Relative risk to sensitivity will be calculated and adjusted by
 session; while comparison of overall risk will performed by McNemar's test. Data on the
 sensitivity level for both scales will be subjected to the Mann-Whitney tests (α = 0.05). The
 color change will be measured with a spectrophotometer using the CIE L * a * b * and the L*,
 a * and b * parameter delta data, and ΔE and Δ00, will be individually subjected to two-way
 repeated measures ANOVA test to compare the two bleaching techniques at each evaluation time
 (α = 0.05).