A topical probiotic gel formulation designed for direct oral mucosal application. Participants will apply a thin layer of the experimental probiotic gel directly onto their minor recurrent aphthous ulcer lesion(s) four times daily. The therapeutic regimen will be maintained continuously for a duration of 1 to 2 weeks. Clinical assessments (lesion size; pain intensity via Visual Analogue Scale; and Thongprasom scoring) and salivary microRNA-146a biomarker collections will be systematically performed at baseline, 1 week, and 2 weeks.

Active control topical corticosteroid paste/gel (Triamcinolone acetonide). Participants will apply a thin layer of the triamcinolone gel directly onto the active minor aphthous ulcer lesion four times daily. The treatment will be maintained for a duration of 1 to 2 weeks, matching the experimental arm timeline, with clinical and salivary biomarker assessments scheduled at baseline, 1 week, and 2 weeks.

Topical probiotic gel formulation designed for oral mucosal application. Participants applied a thin layer of the probiotic gel directly onto the active minor aphthous ulcer lesion four times daily. The treatment was maintained for a duration of 1 to 2 weeks depending on individual healing timelines, with clinical assessments scheduled at baseline, 1 week, and 2 weeks.

The size of the target minor recurrent aphthous ulcer will be measured clinically in millimeters using a calibrated periodontal probe. The maximum ulcer diameter will be recorded at baseline, 1 week, and 2 weeks after treatment initiation. Change in ulcer size from baseline will be calculated. A reduction in size indicates clinical improvement and healing.

Pain severity related to the target aphthous ulcer will be assessed using a 0-10 Visual Analogue Scale, where 0 indicates no pain and 10 indicates the worst imaginable pain. Pain scores will be recorded at baseline, 1 week, and 2 weeks after treatment initiation. Change from baseline will be compared between the probiotic gel group and the triamcinolone group. A lower score indicates improvement.

Salivary microRNA-146a expression will be assessed from saliva samples using RNA extraction, reverse transcription, and real-time quantitative PCR. Relative expression will be calculated using the ΔCt and 2-ΔΔCt methods. Expression levels will be compared between baseline and post-treatment values to assess molecular changes related to inflammation and healing.