Dental filling” is a common name for dental treatment, which refers to the process of restoring the hard tissue structure and chewing function of teeth with dental materials such as silver amalgam and resin when there are carious cavities (worm teeth), hard tissue diseases such as wedge-shaped defects, or when there are defects in dental tissues caused by trauma, etc. Usually, when there are carious cavities, the decayed dental tissues have to be removed in order to be repaired, otherwise the lesions will continue to develop, resulting in the loss of fillings and even causing pulpitis and apical inflammation. Usually, when there is a cavity in a tooth, the decayed tooth tissue has to be removed before it can be repaired, otherwise the lesion will continue to develop, causing the filling to fall off and even causing pulpitis, apical inflammation and other dental diseases that “kill you when you have a toothache”. In the treatment of dental caries, sometimes found that some just found the caries hole is very large, this is mostly caused by the following reasons: 1, fossa caries: patients found small black spots on the surface of the teeth, drilling hole is very large, this is due to the direction of the arrangement of the enamel column at the fossa due to the direction of the fossa. 2, neighboring surface caries: caries occurs in the neighboring surface, shallow and medium caries patients can be asymptomatic, the edge of the ridge is not destroyed, the patient is not easy to find caries hole. With the progress of caries, once the marginal ridge collapses, a large carious cavity appears. When caries occurs under the fossa of the occlusal surface, there is only a very small black spot on the surface, but the cavity under the surface enamel (the other end of the enamel column) may be very large, and it is very difficult to find out if no attention is paid to it, and even some patients go for treatment when the cavity has already penetrated deeper into the pulp of the tooth and caused severe pain. In addition, when enamel caries is present, the patient has no symptoms and the patient is unaware of them. Once conscious symptoms occur, it is at least a medium-deep caries. In most cases, there is already pulpitis and periapical inflammation. Therefore, you should go to the hospital for regular checkups (half a year and a year), early diagnosis, early treatment, good results, less pain and less cost. Caries damage to the teeth, most of the gradual development from the surface to the inside, clinically divided into shallow caries, caries, deep caries. Generally in shallow caries teeth only enamel is destroyed, the patient subjective no pain symptoms, then if not timely to the hospital treatment, the lesions will be to the deeper layers of the teeth, and then formed in caries, deep caries, and will even develop into pulpitis. Once it develops into pulpitis or apical inflammation, endodontic treatment is required, which will cause great pain to the patient. Therefore, if caries is found, even if it does not hurt, it should be filled in time.