Dens invaginatus type II associated with an impacted mesiodens: a 3-year follow-up.

Dens invaginatus is a developmental anomaly resulting in a deepening or invagination of the enamel organ into the dental papilla prior to calcification of the dental tissues. The prevalence has been reported to vary from 0.04% to 10%. Dens invaginatus commonly affects lateral incisors and very rarely affects the mesiodens. This article presents a rare case of type II dens invaginatus affecting an impacted mesiodens in a 13-year-old boy and describes its gross and histological features. The associated tooth was dilated and showed invaginated enamel and dentin extending beyond the cement enamel junction. In this case, the clinical diagnosis was confirmed by histological evaluation of the internal morphology using a hard tissue microtome to section the tooth.