Orthodontic extrusion: diagnosis and treatment with CBCT in a pediatric patient.

Traumatic injury to a primary tooth can affect the underlying permanent tooth germ, and may result in a malformed, hypoplastic crown or root. The degree and nature of malformation depends on the injury. Most trauma cases can be diagnosed using conventional 2-dimensional radiographs, but some cases may benefit from more advanced 3-dimensional imaging such as cone-beam computed tomography (CBCT). This report describes the use of CBCT in the diagnosis and treatment planning of a case in which a 10-year-old girl reported with an impacted, recessed central incisor. The tooth was deformed due to trauma at an early age. Conventional 2-dimensional occlusal and periapical radiographs seemed to indicate that the root had almost completely resorbed. This implied that the optimal treatment plan would be the extraction of the central incisor and, later, the placement of an implant with a crown or bridge. However, a 3-dimensional CBCT radiographic examination showed that the tooth root was long and had enough of a crown-to-root ratio to anchor the tooth. The CBCT examination compelled the treating dentists to maintain the central incisor by orthodontically extruding the tooth and then rebuilding it with a bonded composite restoration.