If the tooth is yellowed and decayed, if it does not reach the nerve, you can choose filling and whitening repair; if the tooth is decayed and reaches the nerve, you can choose root canal treatment and then crown repair. 1. Filling and whitening restoration: If the tooth decay does not reach the nerve, it is necessary to clean up the decayed tooth tissues, then choose the appropriate filling material to fill the tooth, and choose the cold light whitening or tooth bleaching measures for the symptoms of yellowing of the tooth, and use resin for restoration at the same time. 2. Crown repair after root canal treatment: tooth decay reaches the nerve of the tooth, you need to carry out root canal treatment on the tooth, two weeks after the tooth does not appear pain, crown repair on the tooth to prevent the tooth from splitting. Tooth yellowing and decay in time to the hospital, according to the degree of tooth decay to choose the best treatment program, so as to avoid aggravation of tooth inflammation.