The type of the RAS, number of lesions for each subject including the wound surface area progression at T3, T4, T5 and T6 compared to T0, as well a complete resolution and any evidence of lesion recurrence. Abbreviations: CC: complete closure; NR: no lesion recurrence; RAS: recurrent aphthous stomatitis; MiRAS: minor recurrent aphthous stomatitis; MaRAS: major recurrent aphthous stomatitis; T0: pre-treatment; T3: second PBM session (three days post first PBM session); T4: three-day follow-up (after complete PBM treatments); T5: two-week follow-up; T6: three-month follow-up.