Surgical and orthodontic treatment after incidental radiographic discovery of a severely infraoccluded primary molar.

: Dentoalveolar ankylosis, the fusion of a tooth with the alveolar bone, is often associated with primary molars and is the main cause of infraocclusion. This report describes an uncommon case of a severely infraoccluded primary first molar associated with loss of space in the maxilla. After anamnesis and a clinical examination, absence of the primary maxillary left first molar was observed. Periapical radiographs revealed a primary molar completely submerged under the gingiva. Cone beam computed tomography was performed to determine the proximity of the ankylosed tooth to the germ of the permanent successor. Treatment planning included the surgical removal of the ankylosed tooth and placement of a removable space regainer. After 18 months, the maxillary first premolar erupted normally. The careful surgical and interceptive orthodontic planning and cooperation of the patient regarding the use of a removable appliance were essential to the treatment success.