Résumé
Recurrent aphthous stomatitis is an inflammatory disease of oral mucosa with unknown etiology. Many factors contribute in the pathogenesis of aphthae including stress, trauma, foods, allergy, hormonal and microbial factors. It has been observed by Hoover CI [1986] that microorganisms are the causative factor in the pathogenesis of aphthous ulcer. This study was conducted with the aim to observe presence or absence of gram positive and gram negative microorganism in the smears of the lesions compared with the scraping of controls. An Analytical cross-sectional study. It was carried out in Dental Out Patient Department of Shaikh Zayed Federal Postgraduate Medical Institute, Lahore. For a period of Six months First 60 subjects with active RAS during last six months were recruited for the study. Age and gender matched 60 subjects without ulcer during last six months were selected on the same day as control group. After taking informed consent, smears from RAS patients and scrapings from matched surfaces of the oralmucosa of controls was taken. Gram +ve and Gram -ve cocci and bacilli were the microorganisms frequently found in the smears of RAS subjects and Gram +ve cocci were observed in the scrapings of Controls. Presence of microorganisms in ulcers suggested that there is superimposed bacterial infection in these lesions