Dens invaginatus (DI) (dens in dente) is a developmental anomaly resulting from an invagination in part of variable depth of the enamel organ into the dental papilla in the surface of the crown before calcification of the dental tissues. They are a target for caries leading to pulp necrosis and apical pathosis, so the diagnosis and early prevention measures are important. When treatment is necessary, conservative, endodontic, and periodontal possibilities are very effective. Surgical interventions are only rarely indicated. This article presents a unique case report of unilateral DI of Type III (Ohlers) involving the maxillary left central incisor as well as a comprehensive review of literature on history, aetiology and classification. Early detection and management are recommended before the development of pulpal and periodontal pathosis that further complicates the prognosis. Postoperative follow-up subsequent to treatment is essential for effective long-term clinical management.