Clinical comparison of diode laser- and LED-activated tooth bleaching: 9-month follow-up

This study aims to evaluate the effect of diode laser- or LED-activated tooth bleaching on color change, tooth sensitivity(TS), temperature variation, and gingival irritation (GI) for 9 months. Thirty-five subjects having anterior teeth with a color of A2 or darker were enrolled in the study. In a split-mouth design, one side of each arch was activated by a diode laser (Epic X, Biolase), and the other side was activated by an LED (Radii Plus, SDI) in conjunction with a bleaching agent (35%, Whiteness HP). The color change was evaluated by subjective (VitaClassic/Vita3D Master Bleachguide) and objective (spectrophotometer, Vita Easyshade) methods for up to 9 months. TS and GI were assessed by visual analogue scale (VAS) and gingival index, respectively, at the same recall periods. During the bleaching, the temperature variation was also recorded using a thermocouple. Statistical analyses were performed (p < 0.05). In the color evaluation, no statistically significant difference was found between diode laser and LED (p > 0.05), except for the 6-month spectrophotometric assessment (ΔE₀₀, ΔE_ab), where higher values were obtained with the laser (p < 0.05). The temperature difference and maximum temperature with diode were found to be significantly higher than LED (p < 0.05). Higher values were obtained with LED when the mean temperatures were compared (p < 0.05). There was no difference between the two activation methods in terms of TS and GI at any of the recalls (p > 0.05). The bleaching activated either with diode laser or LED performed similar clinical performance in terms of effective color change, tooth sensitivity, and gingival irritation with minimum temperature variations.