Soreness of the tooth when drinking water may be caused by chronic periapical periodontitis, resulting in exposed tooth roots. For such patients, desensitizing toothpaste can be used at home. After cleaning the teeth, desensitizing toothpaste can be applied to the exposed root surface for about 20 minutes and then rinsed off to seal the dentin tubules, thus reducing the symptoms of dentin hypersensitivity. Drinking cold water may also cause wedge-shaped defect in the neck of the tooth, which is caused by the incorrect brushing force and brushing method, resulting in a wedge-shaped depressed groove in the neck of the tooth, thus causing tooth soreness. For this kind of patients, resin filling treatment of wedge-shaped defect should be carried out. After the wedge-shaped defect is filled with composite resin material, the tooth soreness after drinking water will be relieved to a great extent.