Occlusal line edema may be present with oral leukokeratosis or white edema, buccal white line. It may be related to prolonged mechanical and other external stimuli. 1.Oral leukokeratosis. Bite line edema may be caused by long-term mechanical and chemical stimuli causing a milky white borderless patch in the buccal mucosa area, or it may be related to long-term smoking. 2. White edema. When long-term smoking chewing betel nut and other stimuli may also cause in the buccal mucosa near the occlusal line, there is a milky white translucent plaque membrane, for benign damage, etiology is unknown. 3. Buccal white line. Occlusal line edema may also be caused by long-term constant stimulation during tooth chewing resulting in positive epithelial keratinization and grayish-white lines on the mucous membrane, which coincide with the shape of the teeth. Bite line edema is often associated with external stimuli, the specific need to go to the hospital combined with clinical symptoms and laboratory tests to determine.