Comparative evaluation of LED- and diode laser-assisted in-office tooth whitening: a pilot randomized clinical study

Light-assisted in-office whitening procedures are widely used in clinical practice; however, comparative clinical data remain limited, particularly when evaluated using objective outcome measures. This exploratory pilot randomized clinical trial aimed to generate preliminary comparative data on two commercially available light-assisted in-office tooth whitening protocols used under their respective manufacturers' clinical recommendations. The study also explored immediate color change, tooth sensitivity, and patient-reported satisfaction to inform the design of future adequately powered randomized clinical trials.

Twelve healthy adult participants (18-45 years) presenting extrinsic or mixed-type tooth discoloration (baseline shade VITA A3 or darker) were randomly allocated into two parallel groups (n = 6 each). One group received whitening with a 35% hydrogen peroxide gel activated by a diode laser device, while the other group underwent whitening with a 25% hydrogen peroxide gel activated by an LED-based device. Tooth color was measured before and immediately after treatment using a digital spectrophotometer (VITA Easyshade V), and color differences (ΔE) were calculated based on CIE L*a*b* coordinates. Post-treatment tooth sensitivity was recorded using a Visual Analog Scale (VAS), and patient satisfaction was evaluated through a structured questionnaire. Statistical analysis was performed using the Mann-Whitney U test.

Both light-assisted interventions resulted in clinically perceptible whitening outcomes (ΔE > 3.3). The LED-assisted group showed a slightly higher median ΔE value (9.71 [IQR 7.64-13.47]) compared with the laser-assisted group (10.87 [IQR 8.91-13.46]; however, the difference was not statistically significant ( Mann-Whitney U test, p = 0.818). Tooth sensitivity scores were higher in the LED-assisted group ( median 3.5 [IQR 3-4]) compared to the diode laser-assisted group (median 2.5 [IQR 2-3]), but the difference did not reach statistical significance (p = 0.065). Patient-reported satisfaction was high in both groups.

Within the limitations of this exploratory pilot randomized clinical trial, both light-assisted in-office whitening protocols were associated with clinically perceptible immediate color changes. No statistically significant differences were detected between the investigated protocols; however, the limited sample size precludes definitive comparative conclusions. These findings should be considered preliminary and require confirmation in larger, adequately powered randomized clinical trials with longer follow-up periods.

This study was registered in the ISRCTN clinical trial registry (ISRCTN62124700) on 24.01.2026.