Surface debris white lesions are associated with necrosis of the overlying epithelium. The necrotic epithelium can be removed with a gauze leaving an erythematous or ulcerated base. Surface debris lesions are usually painful.
A burn of oral mucosa can be caused by heat or chemicals. It presents as a painful ulcer covered by a white to yellow surface. Often the patient can provide a history of burn to confirm the diagnosis. A burn will resolve spontaneously.
Fibrin clot
Candidosis (candidiasis)