Drinking cold water pain mainly has the following reasons: 1, deep caries, that is, tooth decay is particularly deep, manifested in drinking cold water after a period of time slowly appeared pain, and the pain may sometimes last for a period of time, this time to see if there is a cavity on the tooth that hurts. You may always feel that this position didn’t hurt before, but why it hurts now is because the depth of decay was not deep enough before, but now the decay is very close to the nerve, so the pain of tooth decay starts to appear, and you have to go to the hospital as soon as possible to deal with it. If you go early, it is possible to save the nerve and fill the tooth up, if you go late, it is likely to need to pump the nerve to do root canal treatment.2, dentin sensitivity, some people like to eat hard things, wear out the hard tissue on the surface of the teeth, wear off the enamel, dentin exposed to the outside world is very sensitive to external stimuli, which is characterized by a very fast, a drink of cold immediately pain is very obvious, the time is very rapid.3, pain is another situation, such as brushing the tooth, the tooth decay is not deep enough, now the decay has been very close to the nerve, so it is necessary to go to the hospital as soon as possible to deal with the pain of tooth decay. Pain there is another situation, such as brushing the teeth has been horizontal brush the root of the teeth, many people will brush a groove in the root of the teeth, this groove is very close to the dental neural tube, so it is very sensitive. In the face of this situation must pay attention to, dentin allergy to be treated with desensitization methods, and brush out of a groove can find a way to fill it, to the hospital to fill it up. 4, periodontitis, periodontitis is not under control is likely to cause the entire periodontal atrophy, gum atrophy, atrophy after the exposure of the tooth root, the original long in the bone of the tooth roots exposed after the exposure of the tooth root is very sensitive. 5, tooth decay has been to the stage of chronic pulpitis, but also to the stage of chronic pulpitis. Chronic pulpitis stage, which is also known as the inflammation of the dental nerve, very sensitive to cold and hot stimuli. Therefore, the above series of factors can lead to drinking cold water toothache.