Related Experiment Video
Updated: Jul 11, 2025
Detection and Removal of Tooth-Colored Composite Resin Using the Fluorescence-Aided Identification Technique
Published on: July 27, 2022
The effect of tooth bleaching using violet LED (405-410 nm) on the properties of resin-based composites
Amanda Cavalcante Pereira Pinheiro1, Olívia Vieira Aires1, Mariana Rossi Carneiro Gasperini1
1Department of Restorative Dentistry, University of São Paulo, School of Dentistry, Av. Prof. Lineu Prestes 2227, São Paulo, SP, 05508-000, Brazil.
Background:
The objective of this study was to evaluate the effect of bleaching techniques, including or not the use of violet light (405-410 nm), on resin-based composites' color, surface roughness, nanohardness, and elastic modulus.
Methods:
Ninety-six disk-shaped specimens (12 mm x 2 mm; n = 12) were prepared using Filtek Z350 XT (Z350) and IPS Empress Direct (ED) resin-based composites. After 24 h, specimens were stained in red wine for 28 days. After staining, specimens were divided into four experimental groups: 40 % Hydrogen Peroxide (HP); Violet Light (VL); 40 % Hydrogen Peroxide associated with Violet Light (HP+VL), and a control group - no treatment (NT). Specimens were evaluated at six experimental times: initial (24 h after light curing); after staining and after the 1st, 2nd, 3rd, and 4th bleaching sessions regarding the color change (ΔE00, L*, a*, b*, and WID); roughness (Ra), nanohardness and elastic modulus (GPa). Two-way analysis of variance for repeated measures was performed (α=0.05 %).
Results:
There was a statistically significant difference between staining and the 1st bleaching session for all ED groups (p<0.05). After the last bleaching session, there were no differences between the experimental and the control groups of both resin-based composites. Bleaching using violet light did not change the roughness, nanohardness and elastic modulus of the tested resin-based composites (p>0.05).
Conclusions:
Although hydrogen peroxide and violet light remove pigments from resin-based composites without affecting their surface roughness, nanohardness, and elastic modulus, the color change was similar to the one obtained by immersion in distilled water.
