Journal of Interdisciplinary Dentistry

: 2011  |  Volume : 1  |  Issue : 2  |  Page : 111--114

Multidisciplinary approach for the treatment of bilateral fusion of maxillary central incisors with mesiodens

Gagan R Jaiswal1, Shradha G Jaiswal1, Kiran H Chaoji2, Sandhya C Dharshiyani3,  
1 Sri Aurobindo College of Dentistry, Nagpur, India
2 VSPM'S Dental College and Research Centre, Nagpur, India
3 Modern Dental College and Research Centre, Indore, India

Correspondence Address:
Shradha G Jaiswal
Sri Aurobindo College of Dentistry, Nagpur


Gemination and fusion are developmental anomalies which are quite similar to each other but can be distinguished from each other if properly assessed. Fusion and gemination have been described as a result of developmental anomalies of dental tissues. The exact etiology is still unknown, but a genetic predisposition is suggested. These anomalies are more prevalent among primary teeth (0.6-2.8%) than permanent ones (0.1-1%). The purpose of this case report is to describe a multidisciplinary approach in the treatment of bilateral fusion between permanent maxillary central incisors and two mesiodens. When the various specialities of dentistry come together the outcome is much better than that achieved by each speciality alone.

How to cite this article:
Jaiswal GR, Jaiswal SG, Chaoji KH, Dharshiyani SC. Multidisciplinary approach for the treatment of bilateral fusion of maxillary central incisors with mesiodens.J Interdiscip Dentistry 2011;1:111-114

How to cite this URL:
Jaiswal GR, Jaiswal SG, Chaoji KH, Dharshiyani SC. Multidisciplinary approach for the treatment of bilateral fusion of maxillary central incisors with mesiodens. J Interdiscip Dentistry [serial online] 2011 [cited 2020 Jul 14 ];1:111-114
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Developmental dental disorders may be due to abnormalities in the differentiation of the dental lamina and the tooth germs (anomalies in number, size and shape) or due to abnormalities in the formation of the dental hard tissues (anomalies in structure). [1] In some, both stages of differentiation are abnormal. Developmental dental disorders are not only congenital but they may also be inherited, acquired or idiopathic. [2] The terms "double tooth", "double formations", joined teeth" or "fused teeth" are often used to describe gemination and fusion, both of which are primary developmental abnormalities of the teeth. [3] In the primary dentition, the frequency of gemination or fusion is about 2.5%. Bilateral presentation is very rare. [4] A survey of the literature has revealed prevalence estimates for bilateral double teeth ranging from 0.01 to 0.04% in the primary, and 0.05% in the permanent dentition. [5]

Gemination is defined as an attempt to make two teeth from one enamel organ. This results in a structure with two completely or incompletely separated crowns with a single root and root canal. [6] Occasionally we see complete cleavage or twinning (two teeth from one enamel organ). The etiology is unknown, but trauma has been suggested as a possible cause, though a familial tendency has been suggested. [7] Gemination is observed in the deciduous as well as in the permanent dentition. [8]

Fusion is defined as the union of two separate tooth buds. These anomalies develop when the adjacent tooth bud come very close to each other by resorption of the interdental bone. [9]

If this occurs between the normal complement of teeth then it results in decrease in the number of teeth. But if the fusion occurs between a normal and a supernumerary tooth then the number of teeth remains the same. [10]

Aesthetic rehabilitation is a procedure in which the functional, anatomic and aesthetic restoration of tooth or teeth is achieved. This case report describes the aesthetic rehabilitation of a unique case of fusion between the permanent maxillary central incisors and bilateral mesiodens.

 Case Report

A 19-year-old male patient reported with the complaint of aesthetically poor teeth. Examination revealed two extra large maxillary central incisors. All other teeth were normal and also the normal complement of teeth was present.

Clinically 11 showed an extra large crown with no fissure or indentations while 21 showed slightly overlapping crowns, a groove extending on the labial surface which gave the appearance of two teeth overlapping each other [Figure 1].{Figure 1}

Intraoral periapical X-ray showed 11 to have a large crown, single root and a single wide root canal while 21 showed the presence of two roots, two root canals and overlapping crowns in which the dentine was confluent [Figure 2].{Figure 2}

Treatment plan included root canal therapy followed by crown lengthening procedure and metal fused to ceramic crowns.

Root canal therapy

Access cavities were prepared and distinct pulp chambers with canal orifices found. K-files size 10 (Dentsply Maillefer, Ballaigues, Switzerland) were inserted into the orifices and the working lengths established 0.5 mm from the radiographic apex. The canals were instrumented using the crown-down technique (Morgan and Montgomery 1984) to a size 25 master apical file. Copious irrigation with 2.5% sodium hypochlorite solution was used during the preparation. The canal system was dressed with a non-setting calcium hydroxide paste and sealed temporarily with Cavit-W (ESPE, Seefeld, Germany). No antibiotics were administered. The canals were obturated with gutta-percha points and a zinc-oxide eugenol sealer using cold lateral condensation.

Crown lengthening procedure

This technique is generally used to improve aesthetics and takes the form of a gingivectomy to excise the soft tissue. Adequate attached gingiva was available labially hence an inverse bevel incision was made using a number 11 blade, 2-3 mm from the gingival margin, following a scalloped pattern around the gingival margins. This was followed by a second incision into the intracrevicular sulcus. The incision was extended distally to blend into the gingival sulcus of the untreated teeth. A full-thickness flap was raised to allow bone exposure for the osseous recontouring. Palatally, a scalloped inverse bevel incision using a number 11 blade was made following a scalloped pattern. After the bone recontouring, the flap was then recontoured to follow the new position of the bone. Bone recontouring was carried out using fissure burs and coarse diamond stones with copious amounts of normal saline. The bone was thinned until there was a thin layer remaining over the surface. Then any bone ledges were smoothed to aid the repositioning of the flap. Enough bone was removed to create a 3-mm space between the crest of the bone and the new restoration's margin. Continuous sutures are used to close the flap.

Crown preparation

Tooth modification for receiving a crown was done by reduction on incisal, buccal, mesial, distal and palatal surface of each of the clinical crowns in left and right maxillary central and lateral incisors. Full chamfer margin was made on each tooth. Tooth reduction done was more extensive on the distal margin of the central incisors in order to correct the amorphous shape of the maxillary central incisors [Figure 3] and [Figure 4].{Figure 3}{Figure 4}

The impressions of the prepared teeth were obtained utilizing polyether based elastomeric impression material (Impregum Penta H, Duosoft Grant L, Duosoft, 3M Espe) After casting the model, all ceramic cores were manufactured utilizing heat-press ceramic technique (IPS Empress 2, Ivoclar, Schaan, Liechtenstein) with # 100 lithium disilicate ceramic ingots. After the heat-press procedure, completed ceramic cores were ready for try in procedures. Final restoration was conducted by layering technique (Empress 2 Dentine Ivoclar, Schaan). Crowns were bonded to the prepared abutments using dual cure composite resin luting cement (Rely-X ARC, 3M-ESPE). These fixed restoration treatment resulted in marked improvement in the aesthetics of the anterior region and also enhanced periodontal health [Figure 5].{Figure 5}


The terminology dental fusion and gemination are used to define two different morphological dental anomalies, characterized by the formation of a clinically wide tooth. Despite the considerable number of cases reported in the literature, the differential diagnosis between these abnormalities is difficult. [11] Case history and clinical and radiographic examinations can provide the information required for the diagnosis of such abnormalities.

The differential diagnosis between fusion and gemination, based on the number of teeth present on the dental arch, is not, however, always possible. [9] This is because nothing impairs the fusion between a "normal" and a supernumerary element while the contiguous "normal" tooth is congenitally absent, resembling clinical cases of gemination. [12]

The phenomenon of gemination arises when two teeth develop from one tooth bud and, as a result, the patient has a larger tooth but a normal number, in contrast to fusion where the patient would appear to be missing one tooth. [13] Fused teeth arise through union of two normally separated tooth germs, and depending upon the stage of development of the teeth at the time of union, it may be either complete or incomplete. On some occasions, two independent pulp chambers and root canals can be seen.

Cases of bilateral fusion are less frequent than unilateral fusion. The anomaly can cause unpleasant aesthetic appearance due to irregular morphology. This case can be said to be that of fusion because the complete complement of teeth was present. Also the teeth were larger in their overall dimensions as compared to the other teeth. 11 showed complete fusion resulting in confluent enamel, dentin and pulp while that of 21 was incomplete with only confluent dentin and pulp.

After a judicious evaluation of all information we can report that this case represents bilateral fusion of permanent maxillary central incisors with bilateral mesiodens.

In this case, restoration of all the four maxillary anterior teeth was preferred due to the wide and amorphous shape of maxillary central incisors. As the restorative procedure was extensive hence root canal therapy was performed on all the four teeth. For aesthetic satisfaction, wideness of these teeth was divided and distributed and was shared among the lateral incisors and the canines and a crown lengthening procedure was carried out.

Different cases require a variety of knowledge about alternative operative techniques procedures and abilities. Hence a multidisciplinary approach contributes to the success of the treatment.

Clinical relevance

Dental fusion is a developmental disturbance which can be encountered by the dentist in the clinics. A complete knowledge of the aetiology, pathogenesis and various treatment modalities available will contribute to the success of aesthetic rehabilitation of the patient.


1Aguilo L, Gandia JL, Cibrian R, Catala M. Primary double teeth. A retrospective clinical study of their morphological characteristics and associated anomalies. Int J Paediatr Dent 1999;9:175-83.
2O Carroll MK. Fusion and gemination in alternate dentitions. Oral Surg Oral Med Oral Pathol 1990;69:655.
3Duncan WK, Helpin ML. Bilateral fusion and gemination: A literature analysis and case report. Oral Surg Oral Med Oral Pathol 1987;64:82-7.
4Neves AA, Neves ML, Farinhas JA. Bilateral connation of permanent mandibular incisors: A case report. Int J Paediatr Dent 2002;12:61-5.
5Terezhalmy GT, Riley CK. Gemination/fusion. Quintessence Int 1999;30:437.
6Blank BS, Ogg RR, Levy AR. A fused central incisor. Periodontal considerations in comprehensive treatment. J Periodontol 1985;56:21-4.
7Nunes E, de Moraes IG, de Novaes PM, de Sousa SM. Bilateral fusion of mandibular second molars with supernumerary teeth: Case report. Braz Dent J 2002;13:137-41.
8Jarvinen S, Lehtinen L, Milen A. Epidemiologic study of joined primary teeth in Finnish children. Community Dent Oral Epidemiol 1980;8:201-2.
9Maibaum WW. Fusion of confusion? Oral Surg Oral Med Oral Pathol 1990;69:656-7.
10Milano M, Seybold SV, McCandless G, Cammarata R. Bilateral fusion of the mandibular primary incisors: Report of case. ASDC J Dent Child 1999;66:280-2.
11O'Reilly PM. Structural and radiographic evaluation of four cases of tooth fusion. Aust Dent J 1990;35:226-9.
12Peretz B, Brezniak N. Fusion of primary mandibular teeth. Report of case. ASDC J Dent Child 1992;59:366-8.
13Velasco LF, de Araujo FB, Ferreira ES, Velasco LE. Esthetic and functional treatment of a fused permanent tooth: A case report. Quintessence Int 1997;28:677-80.