A 2-year-old child who has lost a piece of tooth can be treated with grinding and composite resin filling according to the location of the tooth. 1. Sharpening: If the knocked out piece of tooth is limited to the enamel and there is no pain, the sharp tip of the tooth can be sharpened to avoid causing traumatic ulcers. 2. Composite resin filling: If a tooth is knocked out in a deeper position and reaches dentin or there is pain from hot, cold, sour or sweet stimulation, it is necessary to fill the tooth with composite resin, but try not to use the affected tooth to eat hard food in order to prevent the filling material from falling off. 2-year-old child teeth knocked out a piece, there may be other treatment measures, it is recommended to go to the hospital in a timely manner, according to the examination to choose the best treatment program.