Premature tooth eruption, also known as premature tooth eruption, refers to the time when the tooth erupts ahead of the normal eruption time, and the root development of the erupted tooth is less than 1/3 of the root length. 1, premature eruption of milk teeth There are two phenomena: birth teeth and newborn teeth. Birth teeth refer to the teeth that are already in the baby’s mouth at birth, while newborn teeth are the teeth that erupt soon after birth. The causes of these two phenomena are still unclear. Birth and neoplastic teeth occur mostly in the mandibular incisors. Treatment principles:Early eruption of extremely loose milk teeth should be extracted in time; but sucking, due to the friction of the lower incisors on the lingual ligament, resulting in traumatic ulcers at the lingual ligament (i.e. Lee-Fever disease), need to change the feeding method, and local rubbing gentian violet or wait for its natural healing. 2. Early eruption of permanent teeth is mainly related to periapical lesions or premature loss of molar teeth, because periapical lesions of molar teeth destroy the bone around the permanent tooth germ to be replaced below, and then the permanent teeth grow out without resistance. Usually this early eruption is extremely loose and is often accompanied by poor mineralization of the enamel (i.e., the outermost part of the tooth visible to our naked eye) or enamel hypoplasia. Treatment principles: first, control of periapical inflammation of the papillary molars is the top priority; second, depending on the looseness of the prematurely erupted tooth and the presence or absence of the opposing teeth, eruption blocking treatment is given.