Contribution of a* to Dental Bleaching After Combined Dental Bleaching

April 30, 2026 updated by: José Amengual Lorenzo, University of Valencia

Contribution of the a* Parameter to Dental Bleaching After Combined Bleaching: A Prospective Non-randomized Single-arm Interventional Clinical Study

A prospective, non-randomized, single-arm interventional clinical study with a before-after design will be conducted to assess changes in CIELab color parameters and the Whiteness Index for Dentistry (WID) following a standardized combined dental bleaching protocol. The study aims to evaluate the contribution of the a* parameter (green-red axis) to overall dental whiteness.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Tooth whitening is one of the most commonly requested aesthetic dental treatments, requiring objective and reproducible methods to quantify color changes. The CIELab color system (L*, a*, b*) and the Whiteness Index for Dentistry (WID) are widely used for this purpose.

While increases in L* and decreases in b* are recognized as the main contributors to dental whitening, the role of the a* parameter remains unclear. Variations in a*, including the presence of negative values or changes in sign during treatment, have been insufficiently studied.

A prospective, non-randomized, single-arm interventional clinical study with a before-after design will be conducted to evaluate changes in L*, a*, b*, and WID following a combined dental bleaching protocol consisting of an in-office phase with hydrogen peroxide and an at-home phase with carbamide peroxide.

Spectrophotometric measurements will be performed at baseline, after the in-office phase, and after completion of the at-home phase. The study will also analyze the relationship between changes in CIELab parameters and WID.

The study will be conducted in accordance with ethical standards and will be approved by the corresponding institutional review board. All participants will provide written informed consent prior to inclusion.

Study Type

Interventional

Enrollment (Estimated)

10

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Rubén Agustín Panadero, MSc; Phd
  • Phone Number: +34653098901
  • Email: ruben.agustin@uv.es

Study Locations

  • Spain
    • Valencia
      • Valencia, Valencia, Spain, 46010
        • University of Valencia
        • Contact:
        • Contact:
        • Principal Investigator:
          • José Amengual-Lorenzo, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria

  • Age 18 to 65 years
  • Good oral health
  • Presence of natural anterior teeth (incisors, canines, premolars)
  • Anterior teeth without restorations
  • Indication for tooth bleaching treatment
  • Ability to comply with study procedures and visits

Exclusion Criteria

  • Smoking
  • Previous tooth bleaching treatment
  • Pregnancy
  • Breastfeeding
  • Restorations in anterior teeth
  • Presence of diseases affecting tooth color
  • Conditions that may interfere with study outcomes

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Combined Dental Bleaching
Participants will undergo a combined dental bleaching treatment consisting of an in-office phase followed by an at-home phase using custom trays.
Procedure: Combined Dental Bleaching
The intervention consists of an in-office bleaching phase with two 20-minute applications of 40% hydrogen peroxide, followed by an at-home bleaching phase using 16% carbamide peroxide applied with custom trays for 90 minutes daily. Treatment will continue until color stabilization is achieved, defined as a change in WID of less than 2.6 units between two consecutive weekly measurements.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Whiteness Index for Dentistry (WID)
Time Frame: From baseline to end of treatment (up to 12 weeks).
Change in WID values calculated from CIELab parameters (L*, a*, b*) between baseline and the end of treatment (up to 12 weeks).
From baseline to end of treatment (up to 12 weeks).

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in L* parameter
Time Frame: Baseline to end of treatment (up to 12 weeks).
Difference in L* values between baseline and the end of treatment (up to 12 weeks) measured using spectrophotometry.
Baseline to end of treatment (up to 12 weeks).
Change in a* parameter
Time Frame: Baseline to end of treatment (up to 12 weeks).
Difference in a* values between baseline and the end of treatment (up to 12 weeks), including assessment of sign changes.
Baseline to end of treatment (up to 12 weeks).
Change in b* parameter
Time Frame: Baseline to end of treatment (up to 12 weeks)
Difference in b* values between baseline and the end of treatment (up to 12 weeks), measured using spectrophotometry.
Baseline to end of treatment (up to 12 weeks)
Correlation between WID and CIELab parameters
Time Frame: At end of treatment (up to 12 weeks).
Assessment of the relationship between changes in WID and changes in L*, a*, and b*.
At end of treatment (up to 12 weeks).

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Valencia

Investigators

  • Principal Investigator: José Amengual-Lorenzo, University of Valencia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

July 1, 2027

Study Completion (Estimated)

July 1, 2027

Study Registration Dates

First Submitted

March 25, 2026

First Submitted That Met QC Criteria

April 23, 2026

First Posted (Actual)

May 1, 2026

Study Record Updates

Last Update Posted (Actual)

May 6, 2026

Last Update Submitted That Met QC Criteria

April 30, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • Bleaching_aStar_WID_2026
  • Application Reference 2026-ODO (Other Identifier: Ethics Committee University of Valencia)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared, as this is not necessary to achieve the study's objectives or to interpret the results. All findings will be summarized statistically without revealing individual participant information, thereby ensuring privacy and confidentiality. Individual anonymized data will not be shared, as aggregated data is sufficient to ensure scientific transparency and the reproducibility of the results.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Healthy

Clinical Trials on Combined Dental Bleaching

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Gabon

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe