Resorption: within or without? The benefit of cone-beam computed tomography when diagnosing a case of an internal/external resorption defect.

Maxillary canines are the second most common teeth to become impacted, following third molars. Variable levels of incidence have been reported but roughly fall between 1-2.5%. The aetiology of impaction is unknown but both environmental and genetic factors have been suggested. The majority of impacted canines are palatally displaced and such ectopic teeth can be associated with various complications. Rarely this may include cystic or tumourous lesions of the dental follicle or, more commonly, resorption of adjacent teeth. This has a reported incidence of between 12% and 68% depending on the modality of diagnosis and the population sampled. With overlapping teeth causing superimposition on developed images, the diagnostic accuracy of intra-oral radiographs may be reduced. Conventional tomography also exhibits blurring of images and this again reduces its sensitivity. For this reason, Cone Beam Computed Tomography may be beneficial in selected cases of tooth resorption.