2016-10-18 02:08:21 | BioPortfolio


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).


Methods & Materials: This clinical trial was approved by the Scientific Review Committee and by the Committee for the Protection of Human Subjects of the local university (CAAE 50511415.1.0000.5546).

Trial design: This study will be a randomized-controlled, single-blind clinical trial with a parallel design. The patients included will be submitted to two in-office bleaching sessions with a 7-day interval receiving 35% hydrogen peroxide (control) or 37% carbamide peroxide in a single application of 45 minutes; while the same treatments will be allocated for each session. The study will be conducted at the clinic of the School of Dentistry of the local university from May 2016 to December 2016.

Participants: Patients included in this clinical trial will be at least 18 years old with good oral health. Patients with any of the six upper anterior teeth with caries, restoration, severe discoloration (e.g., stains caused by tetracycline), enamel hypoplasia, gingival recession, dentin exposure, pulpitis, or endodontics will be excluded. Participants submitted to previous bleaching procedures, presenting prior tooth sensitivity, pregnant or breastfeeding will be also excluded. Only patients presenting all six upper anterior teeth with shade mismatching with 2.5 M2 (Vita Bleach guide 3D-Master scale, Vita-Zahnfabrik, Bad Sackingen, Germany) or darker will be included.

Sample Size Calculation:

The sample calculation will be based on the primary continuous outcome for superiority control. Power of the test will be set at 80%, considering a type I error of 0.05; for a minimum detectable difference between treatments 25%, based on a prior study using similar bleaching agent, while a coefficient of variation of 30% of control treatment will be expected. The calculation resulted in fifty patients, through the formula used n = f(α/2, β) × [p1 × (100 − p1) + p2 × (100 − p2)] / (p2 − p1)2. The calculation resulted in fifty patients.


A randomized list will be computer-generated by a person not involved in intervention or evaluation. The participants were defined as blocks in the randomization process, where the sequence of treatment (treatment or control) will be randomly set for each block by using computer-generated tables ( The sequence will be inserted into sealed envelopes numbered from 1 to 50 that were opened by the operator only at the moment of the intervention. The patients were numbered according to the sequence of enrollment. Neither the participant nor the operator knew the group allocation determining blinding to the protocol.

Baseline evaluation:

Prior to bleaching procedure, the teeth will be cleaned using rubber cups associated to pumice and water. The shades of canine upper teeth will be assessed on a baseline with a spectrophotometer Vita EasyShade (Vita-Zahnfabrik, Bad Säckinge, Germany) using the CIE L * a * b *. 3 measurements on each tooth will be conducted, with the end result the average of 3 values (L *, a * and b *).


Control treatment: A light-cured resin dam will be applied (Top Dam, FGM, Joinville, SC, Brazil) on the gingival tissue corresponding to the teeth to be bleached. A 35% hydrogen peroxide based bleaching agent (Whiteness HP Maxx, FGM, Joinville, SC, Brazil) will be mixed and applied on the vestibular surface of teeth, in the ratio of 1 drop every 3 to the thickener and peroxide, remaining for 45 minutes. After this time, the bleaching agent will be removed. A second session will be as carried out after 1 week following the same procedures.

Experimental Treatment: A 37% carbamide peroxide based bleaching agent (Power bleaching, BM4, Palhoça, SC, Brazil) will be applied on the vestibular surface of teeth with a relative isolation only using cotton roller, remaining for 45 minutes. After this time, the bleaching agent will be removed. A second session will be as carried out after 1 week following the same procedures.


The tooth sensitivity reported by patients will be assessed using a visual analog scale (VAS) and verbal rating scale (VRS). The VAS consisted of a scale 10 cm in length ranging from 0 (absence of pain) to 10 (unsupportable pain). The patient set his or her level of sensitivity by pointing on the scale corresponding to this level, while the distance from this point to the 0 border will be recorded. For VRS, the patient reported his or her level of sensitivity based on scores: 0 = none, 1 = light, 2 = moderate, 3 = considerable and 4 = severe. The tooth sensitivity will be assessed during the bleaching, immediately after bleaching agent removal and and up to 24 hours after each session. One week after each session and 30 days after the last session the tooth color will be evaluated again using the CIE L * a * b * as previously described.

Statistical Analysis:

For color analysis, the parameter delta data L *, a * and b *, 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. Based on presence of any tooth sensitivity (scores different from 0 for VRS), the absolute risk, odds ratio and relative risk will be calculated regarding the treatments for each moment of evaluation/session of bleaching, as well as its confidence intervals (95%). For each moment, differences on presence/absence ratios will be analyzed by Fisher's exact test. For the overall risk related to each treatment, the odds ratio will be adjusted to independent variable "session of bleaching" using the Mantel-Haenszel statistic. The homogeneity of odds ratios will be analyzed by the Breslow-Day and Tarone's tests. Following, the odds ratio estimated will be converted to relative risk and the overall presence/absence ratios will be analyzed by the McNemar's test, considering the study design (parallel).

For VRS, the data from scores observed in each time of evaluation/session of bleaching will be submitted to the Mann-Whitney rank sum test. Despite the measurement of tooth sensitivity using VAS giving a continuous outcome, data assessed with this scale did not show a normal distribution (Shapiro-Wilk's test). Thus, data from VAS will be also analyzed by the Mann-Whitney rank sum test, while one test per time of evaluation will be carried out. All statistical analyses will be performed considering a 95% significance level (α = 0.05).

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Single Blind (Investigator), Primary Purpose: Treatment


Tooth Bleaching


37% Carbamide Peroxide, 35% hydrogen Peroxide


Active, not recruiting


Universidade Federal de Sergipe

Results (where available)

View Results


Published on BioPortfolio: 2016-10-18T02:08:21-0400

Clinical Trials [260 Associated Clinical Trials listed on BioPortfolio]

Combination of Dental Bleaching Techniques, Randomized Clinical Trial

To determine the effectiveness of combining different concentrations of hydrogen peroxide and carbamide used during tooth bleaching.

Bleaching Tooth of Low Concentration Domestic and Office

To evaluate the efficacy, safety and impact on quality of life related to oral health of home and office tooth whitening techniques in young individuals.

In-office Bleaching Using a Violet Light

The objective of this clinical study is to evaluate the effect of the whitening treatment performed with the violet LED light (405-410 nm), with or without a bleaching gel, on the tooth co...

Efectiveness of a Brief Protocol by a Low (6%) Concentration Gel Peroxide Hydrogen of Teeth Bleaching

The purpose of this clinical study was to evaluate, the effectiveness and sensitivity post-treatment of a 6% hydrogen peroxide with nitrogen-doped titanium dioxide light activated bleachin...

Efficacy of a 6% Hydrogen Peroxide Tooth Bleaching Agent

The present study investigates whether it is possible to achieve equally satisfactory results between 37.5% hydrogen peroxide gel and 6% gel for teeth bleaching. A prospective, double-blin...

PubMed Articles [2614 Associated PubMed Articles listed on BioPortfolio]

Effect of a New Bleaching Gel on Tooth Whitening.

The purpose of this study was to compare the whitening efficacy of a novel bleaching agent containing a unique tribarrel hydremide-peroxide gel (KöR) with a traditional bleaching system of hydrogen p...

Tooth bleaching with low temperature plasma lowers surface roughness and Streptococcus mutans adhesion.

To evaluate the structural-morphological changes in enamel surface roughness and Streptococcus mutans adhesion after tooth bleaching using plasma in combination with a low concentration of 15% carbami...

Hydrogen peroxide induces cell proliferation and apoptosis in pulp of rats after dental bleaching in vivo: Effects of the dental bleaching in pulp.

This study provides an in vivo evaluation of the inflammatory response, levels of cell proliferation and apoptosis, and the presence of necrosis after dental bleaching with two concentrations of hydro...

Method for detection of hydrogen peroxide in HT22 cells.

We have proposed a new method which can be applied in assessing the intracellular production of hydrogen peroxide. Using this assay we have examined the hydrogen peroxide generation during the L-gluta...

Teeth bleaching with low concentrations of hydrogen peroxide (6%) and catalyzed by LED blue (450 ± 10 nm) and laser infrared (808 ± 10 nm) light for in-office treatment: Randomized clinical trial 1-year follow-up.

The aim of this study was to evaluate color longevity after a year of in-office bleaching with gel (6% hydrogen peroxide HP, LED blue/laser infrared activation system) compared to a 35% control concen...

Medical and Biotech [MESH] Definitions

A peroxide derivative that has been used topically for BURNS and as a dermatologic agent in the treatment of ACNE and POISON IVY DERMATITIS. It is used also as a bleach in the food industry.

An enzyme of the oxidoreductase class that catalyzes the conversion of beta-D-glucose and oxygen to D-glucono-1,5-lactone and peroxide. It is a flavoprotein, highly specific for beta-D-glucose. The enzyme is produced by Penicillium notatum and other fungi and has antibacterial activity in the presence of glucose and oxygen. It is used to estimate glucose concentration in blood or urine samples through the formation of colored dyes by the hydrogen peroxide produced in the reaction. (From Enzyme Nomenclature, 1992) EC

A pharmaceutical preparation of adapalene and benzoyl peroxide that is used as a DERMATOLOGIC AGENT for the topical treatment of ACNE.

An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC

Peroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.


Quick Search

Relevant Topics

Dentistry is the study, management and treatment of diseases and conditions affecting the mouth, jaw, teeth and their supporting tissues (Oxford Medical Dictionary) The work of a dentist ranges from regular patient check-up to orthodontics and surgery....

Drug Discovery
Clinical Approvals Clinical Trials Drug Approvals Drug Delivery Drug Discovery Generics Drugs Prescription Drugs In the fields of medicine, biotechnology and pharmacology, drug discovery is the process by which drugs are dis...

Clincial Trials
In a clinical trial or interventional study, participants receive specific interventions according to the research plan or protocol created by the investigators. These interventions may be medical products, such as drugs or devices; procedures; or change...

Searches Linking to this Trial