 This is the most common type of aphthous stomatitis , accounting for about 80 – 85 % of all cases . This subtype is termed minor aphthous ulceration ( <unk> ) , or minor recurrent aphthous stomatitis ( <unk> ) . The lesions themselves may be referred to as minor aphthae or minor aphthous ulcers . These lesions are generally less than 10 mm in diameter ( usually about 2 – 3 mm ) , and affect non @-@ keratinized mucosal surfaces ( i.e. the labial and buccal mucosa , lateral borders of the tongue and the floor of the mouth ) . Usually several ulcers appear at the same time , but single ulcers are possible . Healing usually takes seven to ten days and leaves no scar . Between episodes of ulceration , there is usually an ulcer @-@ free period of variable length . 
