Combined Bleaching Technique: Efficacy and Tooth Sensitivity - A Randomized, Double Blind Clinical Trial
Phase: PHASE4
Conditions: Tooth Bleaching, Tooth Sensitivity
Sponsor: Terezinha de Jesus Esteves Barata

Combined Bleaching Technique: Efficacy and Tooth Sensitivity - A Randomized, 
Double Blind Clinical Trial 
 
ClinicalTrials.gov ID: NCT03089216 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
May 1, 2018 

Objective 
 
This study evaluated the efficacy, color stabilization, and tooth sensitivity 
(TS) during and after the use of a combined bleaching technique, varying the 
application time of 35% hydrogen peroxide (HP) and the use of a desensitizing 
dentifrice containing arginine (ARG).  
 
Study design 
 
This is a randomized controlled clinical trial, parallel and double blinded, with 
a similar allocation rate between groups, registered at clinicaltrials.gov under the 
identification number NCT03089216. The study has being conducting at the School 
of Dentistry of the Federal University of Goias (UFG), following CONSORT 
statement, after the approval of the Ethics Committee of the Federal University of 
Goias, Brazil (CAAE: 52047115.2.0000.5083). 
One hundred and eight participants were randomly assigned to 4 groups (n = 
27): OFF40 (without ARG): two 20-minute HP applications (2x20); D-OFF40 (with 
ARG): two 20-minute applications (2x20); OFF20 (without ARG): one 20-minute HP 
application (1x20); and D-OFF20 (with ARG): one 20-minute HP application (1x20). 
In all groups, at-home bleaching was performed with 10% carbamide peroxide (CP) 
for two hours daily for 16 days. Color evaluations were performed before bleaching 
and at 5, 8, 12, and 16 days from the beginning of the procedure, and 7 and 30 days 
after the end of the treatment, with VITA Classical and VITA Bleachedguide 3D-
MASTER shade guides (SGU) and a digital spectrophotometer, VITA Easyshade 
(VITA Zahnfabrik). The TS evaluation was performed with a visual analogue scale 
(0-10) and numerical scale (0-4) in different periods.  
 
Statistical Analysis Plan 
 
Statistical analyses will be performed using SPSS 20.0 (SPSS Inc., Chicago, 
IL, USA) with  = 0.05. The means of the SGU at baseline and after different 
assessments will be calculated for each group. In order to evaluate whether the 
bleaching therapies were effective or not, the data from the SGUs will be analyzed 
using the Kruskal-Wallis and Mann-Whitney tests for between-group comparisons, 

and the Friedman and Wilcoxon tests with Bonferroni correction ( = 0.002) for 
within-group comparisons. The ΔE values will be submitted to two-way analysis of 
variance (ANOVA). 
The Tooth Sensitivity intensity will be analyzed using Kruskal- among-group 
comparisons within each evaluation time (baseline, immediately after the in-office 
bleaching, daily during the at-home bleaching, and up to 48 hours after the treatment). 
The comparisons among the assessment times within each group will be performed 
using the Friedman and Wilcoxon tests with Bonferroni correction ( = 0.008).