Spectrophotometric Evaluation of Laser-Assisted Dental Bleaching Using Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) and Diode Lasers at Different Wavelengths: An In Vitro Study

Background Dental bleaching is the most common method for managing tooth discoloration, and several light sources have been investigated for accelerating the bleaching process. However, various wavelengths of lasers revealed high effectiveness in tooth color whitening compared to conventional bleaching. This in-vitro study aimed to investigate the effectiveness of erbium-doped yttrium aluminum garnet (Er:YAG) and diode lasers (450 nm, 940 nm, 980 nm) in assisting in-office dental bleaching with hydrogen peroxide (HP), by evaluating tooth whitening according to the Whiteness Index (∆WIᴅ). Materials and methods One hundred enamel samples were obtained from 50 extracted human premolars and divided into five groups (n = 20): control with 38% HP only (first group), 38% HP + Er:YAG laser (second group), 38% HP + 450 nm diode laser (third group), 38% HP + 940 nm diode laser (fourth group), and 38% HP + 980 nm diode laser (fifth group). Tooth shade was assessed pre- and post-bleaching using a spectrophotometer. The Commission Internationale de l'Éclairage L*a*b* (CIELAB) values were obtained, and the ∆WIᴅ values were calculated for each sample. One-way ANOVA test was used to detect significant differences in ∆WIᴅ values among groups, followed by Bonferroni's post-hoc for pairwise comparisons. Results All tested bleaching systems were effective, showing statistically significant differences between groups (p < 0.001). The 940 nm diode laser and Er:YAG laser groups demonstrated superior whitening efficacy (18.13 ± 4.57 and 14.76 ± 6.11, respectively), followed by the 450 nm diode laser group (8.56 ± 7.56), the 980 nm diode laser group (6.74 ± 6.48), and then the control group (4.25 ± 4.67). Conclusion We conclude that laser-assisted dental bleaching significantly enhanced the whitening effect of HP through accelerating the bleaching process with laser energy, with the 940 nm diode laser and Er:YAG laser showing particularly promising results. This can lead to whiter teeth in fewer sessions compared to conventional bleaching.