Comparison of low-power and defocused high-power diode lasers for the treatment of recurrent aphthous stomatitis: a clinical trial

Abstract

Purpose: Recurrent aphthous stomatitis (RAS) is a common oral ulcer for which various treatments have been proposed. The present study aims to compare the effectiveness of low-power and high-power defocused diode lasers in treating RAS, which has not been evaluated previously. Methods: This single-blinded clinical trial included 26 patients suffering from minor RAS, who were randomly assigned to two equal groups. One group received photobiomodulation with a 660-nm diode laser, applied in close contact and perpendicular to the lesion, at a dose of 6 J/cm², while the other group was treated with a high-power 810-nm diode laser (2 W, CW, 0.5-cm distance, 300-µm fiber, 30 s). Data were recorded on pain intensity (at four time intervals), lesion size changes, pain-free time, complete healing time, and relapse frequency over six months. These data were then analyzed using SPSS version 22 with Friedman and Wilcoxon tests at a 0.05 significance level. Results: Significant differences were observed in pain intensity across time intervals for both low-power and high-power laser treatments, as well as in lesion size reduction within each treatment group (p < 0.001). However, no significant differences were found between the two groups in pain-free time (p = 0.979), clinical healing time (p = 0.548), or recurrence frequency (p = 0.455). Conclusions: The high-power 810-nm defocused diode laser demonstrated greater immediate pain reduction after irradiation than the low-power 660-nm diode laser. However, the differences between the two treatments were statistically insignificant for other parameters. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2026.