The majority of swollen face open mouth is caused by inflammatory infections, as follows: 1, wisdom tooth pericoronitis: wisdom tooth pericoronitis is in the wisdom tooth does not grow out of the soft tissue around the crown will form a blind pocket, food and bacteria tend to accumulate in the blind pocket caused by inflammation, gum swelling, pain symptoms; if the inflammation spread to the deep gap, affecting the muscle function, there will be open mouth symptoms; this situation through If the inflammation spreads to the deep interstitial space and affects the muscle function, there will be the symptom of inability to open the mouth; in this case, the symptoms of inability to open the mouth can be slowly relieved through local flushing and medication to flush out the dirty things from the blind pocket, and oral anti-inflammatory drugs, after the inflammation is reduced; 2. The tumor of the buccal area, the tumor behind the molar, and the tumor of the temporomandibular joint will affect the opening of the mouth and cause the symptom of inability to open the mouth.