Which oral condition is NOT caused by local irritation or trauma?

Leukoedema is a developmental/physiological variant of normal buccal mucosa with no relationship to local irritation. Its etiology is unknown (though smoking may exacerbate it). It is NOT caused by trauma, friction, or irritation. In contrast: morsicatio buccarum is caused by chronic self-inflicted cheek biting; traumatic fibroma (irritation fibroma) is the most common oral soft tissue lesion and results from chronic low-grade trauma; oral lichen planus has an immunological pathogenesis (T-cell mediated) though local factors may trigger flares. Leukoplakia can be irritation-related (tobacco) or idiopathic.