The first thing to know is what the cause of the pain is if the tooth becomes painful when it encounters something sweet. If the allergic pain is caused by the heavy wear on the tooth surface, desensitization treatment is needed, you can use anti-allergic toothpaste to brush your teeth, if there is no relief, you can consider going to the hospital for the desensitization treatment method of medicine plus laser. If the pain is caused by caries on the surface of the tooth, it is necessary to go to the hospital for filling treatment in time. Before treatment, it is necessary to take x-ray film to judge the depth of caries, because once the patient has hot and cold as well as sweet and sour stimulation pain, it is very likely that the caries is close to the nerve, and then take the way of padding and pulp protection through certain judgment, and then carry out resin-like material filling on top, which can better protect the pulp of the patient.