Reminder of important clinical lesson CASE REPORT Double tooth in mandibular incisor region: a case report Ravi Prakash Sasankoti Mohan,1 Sankalp Verma,2 Amit Kumar Singh,2 Udita Singh2 1 Department of OMDR, Kothiwal Dental College, Moradabad, Uttar Pradesh, India 2 Department of Oral Medicine & Radiology, Kothiwal Dental College & Research Center, Moradabad, Uttar Pradesh, India Correspondence to Dr Ravi Prakash Sasankoti Mohan, sasan_ravi@rediffmail.com SUMMARY Double tooth is a term used to describe connate tooth and includes both dental fusion and gemination. Fusion refers to the union of two tooth germs resulting in a single large tooth. Owing to its irregular morphology, this anomaly can cause unpleasant aesthetic appearance. The diagnosis is based on the clinical findings and radiographic examination. We hereby discuss a case of fusion in a 30-year-old woman. BACKGROUND Dental anomalies of alteration in number, size and shape are not an uncommon feature in permanent dentition. Although extensive researches have been performed on gemination and fusion there is still much controversy regarding its nomenclature. Various terms been used to describe dental twinning anomalies: gemination, fusion, concrescence, double teeth, cojoined teeth,twinned teeth, geminifusion and vicinifusion. Some authors have tried to differentiate them by counting the number of teeth or by observing the root morphology. While some use fusion and gemination as synonyms. Some authors call it as ‘Double teeth’ or ‘connated’ teeth to avoid the confusion. Figure 1 Clinical photograph showing fusion in mandibular right central and lateral incisor. procedures. If any occlusal interferences are encountered the teeth can be ground in two to three appointments, with an appropriate time period of around 6–8 weeks between the two visits. OUTCOME AND FOLLOW-UP The prognosis was good. CASE PRESENTATION A 30-year-old woman visited the out patient department for routine dental check-up. Clinical evaluation showed a healthy female with no physical abnormalities. Her medical, dental and family history was non-contributory. Intraoral examination revealed a large tooth in right mandibular incisor region whose mesiodistal width was comparatively larger than that of central and lateral incisor of left quadrant (figure 1). There was no percussion or palpation sensitivity on the fused teeth. INVESTIGATIONS Radiography: intraoral periapical radiograph of the right mandibular incisor region showed fused central and lateral incisor with one large pulp chamber and root canal (figure 2). DIFFERENTIAL DIAGNOSIS ▸ Gemination ▸ Twinning To cite: Mohan RPS, Verma S, Singh AK, et al. BMJ Case Rep Published online: [ please include Day Month Year] doi:10.1136/ bcr-2013-008647 TREATMENT A proper endodontic treatment with obturation of the involved teeth followed by their separation and shaping out in required forms. Sharp edges can also be smoothened easily after endodontic Mohan RPS, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-008647 Figure 2 Intraoral periapical radiograph showing fusion in mandibular right central and lateral incisor with one root and one pulp canal. 1 Reminder of important clinical lesson DISCUSSION In 1963, Tannenbaum and Alling defined fusion as a union of two separate tooth buds at some stage in their development.1 There can either be a complete fusion, that is, if the union occurs before calcification begins, the two teeth may be completely be united to form a large single tooth, or incomplete fusion, that is, when only the roots are fused after calcification, and the crown formation.2 The incidence of fusion is 0.1% in permanent and 0.5% in primary dentition with no sex predilection.2 3 Bilateral fusion in permanent dentition is found more frequently in the maxilla than in the mandible. Furthermore, 100% of the permanent bilateral fusion cases seen in the maxilla involve central incisors and 83% of them involve supernumerary teeth.4 The aetiology of fusion is not clearly understood. Some researchers believe that physical pressure and force generated during growth causes contact between two tooth germs. Viral infection and usage of thalidomide during pregnancy is also considered as possible aetiology.5 Dejonge proposed the term ‘synodontia’ to describe adjacent teeth that combine during development.6 Clinically the crowns of fused teeth usually appear to be large and single. A groove (buccolingual or incisocervical) gives a bifid appearance. Dentin7 is always confluent in cases of fusion. Both gemination and fusion appear similar clinically but in gemination there is usually a normal number of teeth in the arch and radiograph show one root and one pulp space with two partially or totally separated crowns. Kelly8 suggested that in gemination the two halves of the joined crowns are usually mirror images, in contrast to fusion, which manifests with a distinct difference in the two halves of the crown.8 The clinical problems associated with fused teeth are esthetics-arch symmetry, spacing, malocclusion. These problems require cosmetic and orthodontic consideration. Learning points ▸ Dental fusion has been defined as the partial or complete union, during development, of two or more adjacent teeth. Fusion can occur between two normal teeth or between a normal tooth and a supernumerary tooth. ▸ Fusion has also been reported with congenital anomalies like cleft lip and X-linked congenital conditions. ▸ Dental fusion results in one tooth less than normal. Competing interests None. Patient consent Obtained. Provenance and peer review Not commissioned; externally peer reviewed. REFERENCES 1 2 3 4 5 6 7 8 Rajeshwari MRC, Ananthalakshmi R. Fusion-case report & review. Indian J of Multidisciplinary Dentistry 2012;2:441–42. Shafer WG, Hine MK, Levy BM. A textbook of oral pathology. 4th edn, Pennsylvania: Saunders, 2002;38–9. Clara M. Spatafore: endodontic treatment of fused teeth. JOE 1992;18:628–63. Duncan WK, Helpin ML. Bilateral fusion and gemination: a literature analysis and case report. Oral Surg Oral Med Oral Pathol 1987;64:82–7. Kjaer I. Interrelation between fusions in the primary dentition and agenesis in the succedaneous permanent dentition seen from an embryological point of view. J Craniofac Genet Dev Biol 2000;20:193–7. Dejonge TE. Beschouwingen over DE syndontie. T Tandheelk 1955;62:828. Alpöz AR, Munanoğlu D, Oncag O. Mandibular bilateral fusion in primary dentition: case report. J Dent Child (Chic) 2003;70:74–6. Kelly JR. Gemination, fusion, or both? Oral Surg 1978;45:655–6. Copyright 2013 BMJ Publishing Group. All rights reserved. For permission to reuse any of this content visit http://group.bmj.com/group/rights-licensing/permissions. BMJ Case Report Fellows may re-use this article for personal use and teaching without any further permission. Become a Fellow of BMJ Case Reports today and you can: ▸ Submit as many cases as you like ▸ Enjoy fast sympathetic peer review and rapid publication of accepted articles ▸ Access all the published articles ▸ Re-use any of the published material for personal use and teaching without further permission For information on Institutional Fellowships contact consortiasales@bmjgroup.com Visit casereports.bmj.com for more articles like this and to become a Fellow 2 Mohan RPS, et al. BMJ Case Rep 2013. doi:10.1136/bcr-2013-008647 View publication stats