 Aphthous stomatitis has been classified as a type of non @-@ infectious stomatitis ( inflammation of the mouth ) . One classification distinguishes " common simple aphthae " , accounting for 95 % of cases , with 3 – 6 attacks per year , rapid healing , minimal pain and restriction of ulceration to the mouth ; and " complex aphthae " , accounting for 5 % of cases , where ulcers may be present on the genital mucosa in addition to mouth , healing is slower and pain is more severe . A more common method of classifying aphthous stomatitis is into three variants , distinguished by the size , number and location of the lesions , the healing time of individual ulcers and whether a scar is left after healing ( see below ) . 
