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.
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
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
10
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.
University of Valencia
Valencia, Valencia, Spain
Change in Whiteness Index for Dentistry (WID)
Change in WID values calculated from CIELab parameters (L\*, a\*, b\*) between baseline and the end of treatment (up to 12 weeks).
Time frame: From baseline to end of treatment (up to 12 weeks).
Change in L* parameter
Difference in L\* values between baseline and the end of treatment (up to 12 weeks) measured using spectrophotometry.
Time frame: Baseline to end of treatment (up to 12 weeks).
Change in a* parameter
Difference in a\* values between baseline and the end of treatment (up to 12 weeks), including assessment of sign changes.
Time frame: Baseline to end of treatment (up to 12 weeks).
Change in b* parameter
Difference in b\* values between baseline and the end of treatment (up to 12 weeks), measured using spectrophotometry.
Time frame: Baseline to end of treatment (up to 12 weeks)
Correlation between WID and CIELab parameters
Assessment of the relationship between changes in WID and changes in L\*, a\*, and b\*.
Time frame: At end of treatment (up to 12 weeks).
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