Tooth splitting is a dental hard tissue disease caused by various external forces on the tooth, which further develops in the molar teeth of middle-aged and elderly patients and can cause complications such as alveolar abscess. To determine whether the tooth splitting reaches the root of the tooth, the diagnosis can be clearly made by clinical symptoms and auxiliary examination. Clinical symptoms: 1. The crown is split in two, the maxillary root is separated in a buccal and palatal pattern, the filling can be dislodged, bloody or purulent secretion is occasionally seen, the degree of looseness is about second degree, accompanied by percussion pain; 2. The palatal crown is split obliquely and dislodged, the splitting surface does not reach the subgingival area, the remaining crown is not loose, no percussion pain; 3. The crown is split obliquely from the palatal cusp to the subgingival area, the degree of looseness of the palatal crown is about third degree, accompanied by percussion pain. Second, auxiliary examination To determine whether the depth of tooth splitting reaches the root of the tooth, the intraoral apical radiographs can be taken to clarify, but there may be a certain chance of missing the diagnosis due to the different angles of the apical radiographs. Depending on the degree of tooth splitting, different restorative methods can be adopted: 1, for dead pulp tooth splitting, most of the metal crowns or braces are used to restore the tooth, which is conducive to protecting the tooth and restoring the chewing function; 2, for the symptoms of tooth splitting with a gap, all-ceramic crowns can be adopted to restore the tooth, which can completely wrap the damaged tooth and protect the dental nerve; in the case of a smaller gap, resin or nano material can be chosen to fill it; 3. For splitting to the root of the tooth, usually need to extract the tooth.