3-year-old baby toothache can be caused by pulpitis, caries (shallow caries and deep caries) and other causes, mostly physical and surgical treatment. 1. Shallow caries: It is mainly because the food residues are retained in the milk teeth, causing gum swelling and pain. Food can be removed by toothpicks and dental floss rinsers, and children should be allowed to eat less coarse-fiber food to reduce the retention of plaque. 2. Deep caries: mainly due to bacterial infection, chronic infection of the teeth, and then chronic destruction of a symptom, when encountered with cold, hot, sweet, sour, etc. will produce pain, you can take a sharp digging spoon to remove the large pieces of decay, and then the use of zinc oxide ointment to temporarily close the hole, to relieve the pain, and then the double matting, repair the damage. 3. Pulpitis: mainly due to trauma or caries and other causes of milk teeth defects but did not get timely treatment, so that the main bacteria through the dental defects infection. The main symptom is toothache. Timely go to the hospital for treatment, under local anesthesia to grind open the pulp cavity and remove the pulp, and then use iodine glycerin to fill it. Family members are usually advised to keep the baby’s oral hygiene habits, master the correct method of brushing teeth, and use dental floss reasonably. Regular oral examination should be conducted once a year for early detection and treatment.