An Immature Type II Dens Invaginatus in a Mandibular Lateral Incisor with Talon’s Cusp: A Clinical Dilemma to Confront

Dens invaginatus (DI) is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. DI is classified as type I, II, and III by Oehlers depending on the severity of malformation. The maxillary lateral incisor is the most commonly affected tooth. Structural defects do exist in the depth of the invagination pits, and as a consequence, the early development of caries and the subsequent necrosis of the dental pulp, as well as abscess and cyst formation are clinical implications associated with DI. Occasionally, we can see more than one developmental anomaly occurring in a single tooth. In such cases it becomes important to identify the anomalies and initiate a proper treatment plan for good prognosis. In this paper, an unusual case of DI which clinically presented as a huge talons cusp affecting a mandibular lateral incisor tooth is described. This case report illustrates grinding of the talons cusp followed by nonsurgical endodontic management of dens invaginatus type II with an immature apex and periapical lesions, in which Mineral Trioxide Aggregate (MTA) shows a complete periapical healing with bone formation at the site of the lesions. 1. Introduction Dens invaginatus (DI), commonly known as dens in dente, is a developmental anomaly resulting from invagination in the surface of a tooth crown before calcification has occurred. Coronal invaginations usually originate from an anomalous infolding of the enamel organ into the dental papilla. The most extreme form of this anomaly is referred to as “dilated odontome.” This kind of malformation was first described by “Ploquet” in 1794 in whale’s tooth [1]. DI was first described as “a tooth within a tooth” by Salter in 1855 [2]. Hallet introduced the term dens invaginatus in order to clarify the point that enamel is located centrally and the dentine peripherally due to the invagination. Since then it has been a preferred term, though dens in dente is a more commonly used term [3]. DI in human tooth was first described by a dentist named Socrates in 1856 [1]. The frequency of its occurrence is 0.04 to 10% of all dental malformations [4]. The permanent dentition is involved three times more commonly than the deciduous dentition. The teeth most affected are the maxillary lateral incisors with a prevalence of 0.25–5.1%, frequently bilateral (43%), followed by central, canines, premolars, and molars. Langlais et al. noted that the mandibular occurrence of this anomaly is rare. The literature review showed only 10 cases involving 13 mandibular teeth with a majority in