This randomized controlled clinical trial was designed to evaluate the efficacy of single-session, non-thermal,
carbon dioxide (CO(2))
laser irradiation in relieving the
pain of minor recurrent
aphthous stomatitis (
miRAS) as a prototype of painful
oral ulcers. Fifteen patients, each with two discrete
aphthous ulcers, were included. One of the
ulcers was randomly allocated to be treated with CO(2)
laser (1 W of power in de-focused continuous mode) and the other one served as a placebo. Before
laser irradiation, a layer of transparent, non-
anesthetic gel was placed on both the
laser lesions and the placebo lesions. The patients were requested to grade their
pain on a visual analog scale up to 96 h post-operatively. The reduction in
pain scores was significantly greater in the
laser group than in the placebo group. The procedure itself was not painful, so
anesthesia was not required. Powermetry revealed the CO(2)
laser power to be 2-5 mW after passing through the gel, which caused no significant temperature rise or any visual effect of damage to the oral mucosa. Our results showed that a low-intensity, non-thermal, single-session of CO(2)
laser irradiation reduced
pain in
miRAS immediately and dramatically, with no visible side effects.