Rare associations of dens invaginatus and mesiodens Eduardo Kazuo Sannomiya, MSc, PhD, a Jun-Ichi Asaumi, PhD, b Kanji Kishi, DDS, MD, c and Gisele da Silva Dalben, DDS, MSc, d São Paulo, Brazil, Okayama, Japan SÃO PAULO METODISTA DENTAL SCHOOL, UNIVERSITY OF SÃO PAULO, AND OKAYAMA UNIVERSITY Dens invaginatus is a developmental variation resulting from an alteration in the normal growth pattern of the dental papilla. Synonyms of this disturbance include dens in dente, invaginated odontome, tooth inclusion, and dentoid in dente. Radiographically, it is observed as infolding of a radiopaque ribbon-like structure, with equal density as enamel, extending from the cingulum into the root canal and sometimes reaching the root apex, assigning the appearance of a small tooth within the coronal pulp cavity. This article presents 2 case reports. The first describes an 8-year-old girl with dens invaginatus in a mesiodens; the second report describes a 16-year-old boy presenting with 2 mesiodens, both associated with dens invaginatus. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104: e41-e44) Dens invaginatus or dens in dente is a tooth abnormal- ity first described by a dentist called Socrates in 1856. 1 It is also called invaginated odontome, dilated gestant odontome, dilated composite odontome, and dentoid in dente. 2 This anomaly originates from invagination of the odontogenic epithelium on the lingual aspect of the tooth crown during odontogenesis. Several theories have been proposed for its etiology: (1) growth pressure of the dental arch causing buckling of the enamel organ 3 ; (2) invagination resulting from rapid and aggressive proliferation of part of the internal enamel epithelium invading the dental papilla 4 ; (3) infection 5 ; and (4) trauma. 6 Several classification sys- tems of dens invaginatus are available; however, the most widely known was proposed by Oehlers, 5,6 who classified 3 types of invagination, as follows: ● Type I: an enamel-lined minor form occurring within the limits of the crown not extending beyond the cementoenamel junction. ● Type II: an enamel-lined form that invades the root but remains confined as a blind sac. ● Type III: a form that penetrates through the root perforating the apical area, showing a second fora- men, or at the periodontal area. Type II was observed in both case reports described in the present paper. CASE REPORT 1 An 8-year-old girl presented to the emergency clinic of the Dental School at São Paulo Methodist University. According to the mother, the reasons for consultation were evaluation of the unerupted maxillary left central incisor and general dental treatment. During clinical examination, the professional ob- served absence of the maxillary left central incisor and also of the deciduous tooth at this region; the patient was in the mixed dentition stage and presented poor oral hygiene. The mother reported history of trauma to the deciduous tooth with consequent tooth loss. A panoramic radiograph was then obtained, which revealed the presence of a supernumerary tooth erupting at the midline; thus, a mesiodens, which con- tained an invagination lined by enamel with aspect of dens invaginatus (Fig. 1). This supernumerary tooth precluded eruption of the maxillary left central incisor in its normal position in the dental arch. Periapical orthoradial and distora- dial radiographs were taken by the Clark technique, which revealed palatal positioning of the mesiodens (Fig. 2, A and B). Treatment planning comprised extraction of the mesiodens followed by orthodontic traction of the maxillary left central incisor to its normal position. CASE REPORT 2 A male patient aged 16 years presented to the orthodontics department of the Dental School at São Paulo Methodist University with the chief complaint of lack of eruption of the maxillary left central incisor. Clinical examination revealed the presence of 2 supernumerary teeth (mesiodens) in the maxilla; the patient was in the permanent dentition stage. Radiographic examination of the region of the maxillary left central incisor revealed that both mesiodens further presented a Professor of Dentomaxillofacial Radiology, Department of Oral and Maxillofacial Radiology, Orthodontics Post Graduate Program, São Paulo Metodista Dental School. b Lecturer, Department of Oral and Maxillofacial Radiology, Okayama University. c Professor of Dentomaxillofacial Radiology, Department of Oral and Maxillofacial Radiology, Dental School, Okayama University. d PhD student in Oral Pathology, Department of Pediatric Dentistry, Hospital for Rehabilitation of Craniofacial Anomalies, University of São Paulo. Received for publication Dec17, 2006; returned for revision Dec 20, 2006; accepted for publication Jan 3, 2007. 1079-2104/$ - see front matter © 2007 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2007.01.005 e41