A translucent opalescent crown is a hereditary papillary tooth, which can be light yellow or brownish yellow. A translucent milky colored crown is usually, hereditary dentin hypoplasia. It is a common oral disease with a high incidence in children. The main presenting symptoms are abnormal calcification and defects in dentin, normal enamel development, but easy separation and loss from the dentin surface, leaving the dentin exposed and causing crown wear. The disease is autosomal dominant and can involve both milk and permanent teeth. The coding gene for the disease is located at 4q13, and it is thought that the disease is associated with abnormal mesodermal development. The diagnosis of translucent opalescence of the crown: microscopically, the dentin tubules are disorganized, the lumen is enlarged, and the number of dentin tubules per unit of dentin is reduced. Some areas of dentin tubules disappear. Degeneration of adult dentin cells with abnormal synthesis and secretion of matrix proteins may be seen. The cells themselves may be encapsulated in the matrix or calcified dentin, with abnormal dentin calcification. As the tooth is further worn, restorative dentin continues to form in the pulp chamber and root canal, up to the point where the entire pulp chamber is filled with restorative dentin. The enamel thickness and morphology are normal, but the lack of serrated interlocking structures at the enamel-dentin boundary makes the dentin and enamel join in a near-linear fashion, with poor mechanical inlay. The development of dentin, periodontium and alveolar bone was normal. The crown of the tooth is translucent and milky in color, which can be light yellow or brownish yellow. The enamel is easily fractured, especially on the incisal edge of the incisors and the molars, and the dentin is exposed. The exposed dentin is highly susceptible to wear and tear, which is manifested by the appearance of dentin planes after heavy abrasion. Radiographs show a large pulp cavity in the early stage, with gradual calcified atresia in the pulp cavity and root canal after enamel abrasion. The periodontal supporting tissues are normal. Sometimes a shell tooth (sheltooth) is seen, showing a large pulp chamber, a thin dentin layer, and abnormally short roots, but no signs of root resorption.