Dental caries is the most common disease in the clinic, then what are the specific clinical symptoms of dental caries, clinically it is often divided into three stages of superficial caries, medium caries and deep caries according to the degree of caries, and the respective performance is as follows. First, shallow caries, also known as enamel caries, the caries is limited to the enamel, the initial stage and the smooth surface is white plaque caused by demineralization, later because of coloring and yellow-brown, the sulcus is golden end-like dispersion, generally there is no obvious cavity, only rough feeling when the probe examination, the late stage can appear shallow cavity limited to the enamel, no conscious symptom, the probe also has no reflection; Second, medium caries, the caries has reached the superficial layer of dentin, the clinical examination has Obvious cavity, can have probing pain, to external stimulation, such as cold, hot, acid, etc. can appear pain response. When the stimulus source is removed, the pain disappears immediately and there is no spontaneous pain; Third, deep caries, the caries has reached the deep layer of dentin, generally manifested as large and deep cavity, or the entrance is small, but the deep layer has more extensive destruction, and the reaction to external stimulus is heavier than medium caries. However, the pain can still be stopped immediately after the stimulus source is removed, and there is no spontaneous pain.