Dens in dente is a developmental variation where the outer surface of the tooth folds into its interior, creating an invagination. It is most commonly seen in permanent maxillary lateral incisors and can extend from the crown to the root apex. Radiographically, it appears as an inverted umbrella shape within the tooth. Treatment focuses on prevention of caries, pulp infection, and premature tooth loss by addressing the invagination prophylactically.