Patient: three-year-old child sometimes eat sugar, every day before bedtime brushing, other teeth are very good, quite white, no cavities, only one incisor in the last two days suddenly turned gray, not partial, is the whole discoloration, the child did not have any pain discomfort, may I ask this situation is caries? Or other reasons? Wang Ruiyong, Department of Stomatology, Beijing Haidian Hospital: It may be pulp necrosis, which should be treated in time. Patient: Dr. Wang, thank you! I’ve taken my child to the hospital, and as you said, it’s pulp necrosis caused by the child’s previous fall. At that time, the doctor said that because it was a baby tooth, as long as it was well protected and there was no other sensation, there was no need for treatment for the time being, saying that it would be replaced directly when the tooth was replaced. Seeing that you said it has to be treated in time, I have questions again. I take my child’s teeth very seriously and they have always been fine, so I didn’t realize that a fall would break the pulp. Could you please explain the necessity and method of treatment again? Wang Ruiyong, Department of Stomatology, Beijing Haidian Hospital: Since the child is only 3 years old, this tooth will not be replaced until he is about 7 years old, and it is estimated that apical periapical inflammation will occur soon, so it is recommended to perform root canal therapy on the baby tooth in time to keep the tooth until the normal replacement time. Treatment can be done at the dentistry department of a regular hospital. If the child does not cooperate, then we will have to wait until there is a problem and then treat it in time. If the child is cooperative, you can go to a specialized pediatric dentistry. Patient: I see. For you said the periapical inflammation is bound to appear? Is there any measure that can be prevented or delayed? Wang Ruiyong, Department of Stomatology, Beijing Haidian Hospital: Not necessarily, if there are no symptoms, you can temporarily observe, and if there is a problem, timely treatment can also be. There is no good preventive measure. Patient: Uh, okay. Thank you again for your reply! Beijing Haidian Hospital stomatology Wang Ruiyong: there are problems can be contacted in a timely manner.