Elsevier

Journal of Dentistry

Volume 43, Issue 8, August 2015, Pages 965-972
Journal of Dentistry

Effectiveness of 6% hydrogen peroxide concentration for tooth bleaching—A double-blind, randomized clinical trial

https://doi.org/10.1016/j.jdent.2015.05.011Get rights and content

Abstract

Objective

The aim of this clinical randomized double-blind split-mouth study was to assess the effectiveness of a 6% hydrogen peroxide with nitrogen-doped titanium dioxide light activated bleaching agent.

Method

31 patients were treated with: one upper hemiarcade with a 35% hydrogen peroxide bleaching agent and the other hemiarcade with a 6% hydrogen peroxide. Two applications were completed each treatment session and three sessions were appointed, with one week interval between them. Tooth colour was registered each session and 1 week and 1 months after completing the treatment by spectrophotometer, registering parameters L*, a* and b*, and subjectively using VITA Classic guide. Tooth sensitivity was registered by VAS and patient satisfaction and self-perception result was determined using OHIP-14. Tooth colour variation and sensitivity were compared between both bleaching agents.

Results

Both treatment showed a change between baseline colour and all check-points with a ΔE = 5.57 for 6% and of ΔE = 7.98 for the 35% one month after completing the (p < 0.05). No statistical differences were seen when subjective evaluations were compared. Also, no differences were seen in tooth sensitivity between bleaching agents. OHIP-14 questionnaire demonstrated a significant change for all patients after bleaching.

Conclusions

A 6% hydrogen peroxide with nitrogen-doped titanium dioxide light activated agent is effective for tooth bleaching, reaching a ΔE of 5.57 one month after completing the treatment, with no clinical differences to a 35% agent neither in colour change or in tooth sensitivity.

Clinical significance

A low concentration hydrogen peroxide bleaching agent may reach good clinical results with less adverse effects.

Introduction

In treatments for most teeth colour alterations, bleaching is the procedure of choice, because (1) it is minimally invasive, (2) it is quick and effective, and (3) it does not wear down tissue, as is the case with fixed prostheses. Patients are becoming more demanding and want effective treatment. The effectiveness of bleaching is defined as a change of at least 5 units of ΔE, which represents an increase in luminosity, mainly with an increase of the value in the colour of the bleached tooth.1, 2

There are reports of cellular damage (to pulp cells) caused by typical concentrations of bleaching gel (38%), which has alarmed authorities, who have taken regulatory measures.3 For example, the European Community banned concentrations above 6% for teeth bleaching procedures. Despite the restrictions, patients will continue consulting for bleaching, and therefore, dentists will have to search for and provide solutions.2, 4

In general, in-office bleaching, with higher concentrations of hydrogen peroxide at 35%, are effective. Manufacturers recommend at least 2 sessions with applications of contact gel for 20 min or more to achieve the result.5 The at home bleaching or similar systems, i.e., over the counter, such as whitening strips, use much lower concentrations of peroxide (6–10%),5, 6 but the contact time is much greater, even up to 20 h for effective bleaching. The challenge is to achieve effectiveness with low concentrations of peroxide to reduce adverse effects and the time in contact with the bleaching gel.

There has been some research into bleaching gels catalyzed by agents such as titanium dioxide nanoparticles activated by hybrid light (laser/LED) with different concentrations (15%).7, 8, 9 These concentrations show similar effectiveness, and in some cases, much lower adverse post-procedure effects. However, only one report10 have used a concentration permitted by the European Community.4, 11 In this report by Vano et al. the patients do not achieve a change of at least 5 units ΔE, which was considered ineffective.10

Soares et al. recently reported on low-concentration (17.5%) and short-duration applications and found significantly reduced cellular damage under in vitro conditions.12, 13, 14 There is interest in RCTs to assess compounds with lower concentration that would comply with standards such as those of the European Community. The objective of this work is to show the effectiveness of a bleaching gel (6%) catalyzed by titanium dioxide nanoparticles and activated by hybrid light. The effectiveness of the concentration was compared with that of a control concentration of 35% in a split-mouth study model. The null hypothesis of this study is that the effectiveness as a main outcome along the different times will be the same between the two gel methods.

Section snippets

Materials and methods

This clinical study was approved by the Ethics Committee of the Faculty of Dentistry at the University of Chile (PRI-ODO 15/01 and FIOUCH 13/18), where the study took place between July 2014 and December 2014. It is registered on the site of the Clinical Trials Registry (NCT02353611) and was conducted according to the Consolidated Standards of Reporting Trials Statement and Helsinsky Declaration of 1975 revised in 2000.

31 volunteers were selected and received a dental prophylaxis and oral

Baseline characteristics

Of a total of 131 patients examined, 31 patients were selected, of which one did not continue in the monitoring. The sample consisted of 11 women (36.67%) and 19 men (63.33%) with average ages of 24.1 ± 5.81 years for men and 25.2 ± 7.4 years for women. There were no differences between the two groups in terms of the characteristics of the baseline colour (p > 0.05), as shown in Table 2, Table 3.

Objectively measured changes

Colour changes measured by units of ΔE from the baseline are shown in Fig. 2 and Table 4. There was a

Discussion

In this randomized clinical study, a treatment was proposed that was thought to be a risky design (split-mouth).22, 23 This was done to demonstrate the effectiveness of a protocol that has not very explored with a very low concentration of hydrogen peroxide (6%). Since there was no certainty that the two compounds tested would have similar effectiveness, there was an explicit statement in the informed consent form indicating that if patients perceived a difference in the colour of their

Conclusions

Within the limitations and protocols of this study, there was a significant difference between the objective effectiveness in the two groups. The two compounds were considered to be effective, and there were no differences in the sensitivity generated between the groups. The intensity of post-operative sensitivity was mild. Patients were satisfied with the bleaching procedure, despite objective differences between both hemiarcades.

Acknowledgements

NUPEN and DMC support the equipment and materials, Carlos Salas, Emilio Rathgeb, Macarena Guajardo, Diego Rivera and Mariel Correa by the involvement in the project. U-Inicia (University of Chile GRANT) by partial support in this project.

References (33)

  • C.A. Costa et al.

    Human pulp responses to in-office tooth bleaching

    Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontics

    (2010)
  • Health ECP. 7

    What Should be Considered Before a Tooth Whitening Treatment?

    (2007)
  • R.A. Basson et al.

    Guidelines for the selection of tooth whitening products amongst those available on the market

    Journal of the South African Dental Association

    (2013)
  • G. Moncada et al.

    Effects of light activation agent concentration, and tooth thickness on dental sensitivity after bleaching

    Operatoria Dental

    (2013)
  • J. Martin et al.

    Dentin hypersensitivity after teeth bleaching with in-office systems randomized clinical trial

    American Journal of Dentistry

    (2013)
  • J.F. Bortolatto et al.

    Low concentration H2O2/TiO_N in office bleaching: a randomized clinical trial

    Journal of Dental Research

    (2014)
  • Cited by (72)

    • Physicochemical evaluation of hydrogen peroxide bleaching gels containing titanium dioxide catalytic agent, and their influence on dental color change associated with violet LED

      2023, Photodiagnosis and Photodynamic Therapy
      Citation Excerpt :

      Some 6%-15% of the hydrogen peroxide agents used at lower concentrations in the in-office technique [10–14] have reduced tooth color up to 5 shades when applying the Vita Classical scale [15]. In these studies, bleaching gels containing catalytic agents achieved the same color change with or without a light source [10,11,13,14,16] as that provided by a high-concentration hydrogen peroxide gel. Titanium dioxide (TiO2) acts as a catalyst and photocatalyst semiconductor, absorbing ultraviolet light (wavelength 388nm) [17,18] and visible light in the blue-violet range [19, 20].

    View all citing articles on Scopus
    View full text