The tooth rotten cavity will not be heeded to the following situations: 1.The food residue embedded in the cavity will cause the pressure to increase and lead to pain. 2.The food residue accumulated in the cavity will produce foul smell under the fermentation of bacteria, and the bacterial metabolites will destroy the tooth tissue continuously to further expand the cavity, and even cause the disintegration and fracture of the tooth tissue. 3.The bacteria in the cavity will infect the tooth pulp, and it will be sensitive to cold, hot, acid, sweet and other stimuli. 4.The repeatedly infected pulp will gradually necrosis, the inflammatory secretion will break through the apical hole and cause the swelling of jaw and face, and the whole body will appear fever and weakness etc.