Journal of Conservative Dentistry
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Year : 2014  |  Volume : 17  |  Issue : 3  |  Page : 293-296
Management of geminated maxillary lateral incisor using cone beam computed tomography as a diagnostic tool

1 Department of Conservative Dentistry and Endodontics, Government Dental College, Calicut, India
2 Department of Oral Medicine, MES Dental College, Perinthalmana, Malappuram, Kerala, India

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Date of Submission08-Sep-2013
Date of Decision06-Dec-2013
Date of Acceptance10-Dec-2013
Date of Web Publication2-May-2014


Geminated teeth are consequences of developmental anomalies leading to joined elements, due to incomplete attempt of one tooth germ to divide into two. This case report describes successful endodontic treatment of an unaesthetic geminated permanent maxillary lateral incisor tooth and its esthetic rehabilitation using all ceramic crowns. Newer imaging technique like cone beam computed tomography was taken for the better understanding of the complicated root canal morphology.

Keywords: Cone beam computed tomography; germination; lateral incisor

How to cite this article:
James EP, Johns DA, Johnson K I, Maroli RK. Management of geminated maxillary lateral incisor using cone beam computed tomography as a diagnostic tool. J Conserv Dent 2014;17:293-6

How to cite this URL:
James EP, Johns DA, Johnson K I, Maroli RK. Management of geminated maxillary lateral incisor using cone beam computed tomography as a diagnostic tool. J Conserv Dent [serial online] 2014 [cited 2020 Sep 29];17:293-6. Available from:

   Introduction Top

Developmental dental disorders may be due to abnormalities in the differentiation of dental lamina and the hard tissues. The presence of two roots, [1] two root canals and two crowns [2] in maxillary anterior dentition have been documented in the literature. 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. The term double tooth, joined teeth are synonyms of gemination. [2] The etiology is unknown, but trauma has been suggested as a possible cause, though a familial tendency has also been suggested. [3] Gemination is observed in deciduous as well as permanent dentition. [4] In the primary dentition, the frequency of gemination is about 2.5%. Bilateral presentation is rare. 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] In the anterior region this anomaly can cause unpleasant esthetic appearance due to irregular morphology. Maxillary central incisors were found to be the most commonly affected by gemination. [6] Several treatment methods have been described in the literature with respect to different types and morphological variations of geminated teeth, including endodontic restoration, surgical, periodontal and orthodontic treatment.

In the clinical situation, cases of fusion have the appearance of congenitally missing tooth while in gemination, the number of teeth in the dentition is normal, provided the double teeth is counted as one unit. [7] Isolated large or double teeth may be the result of union of two adjacent tooth buds or partial splitting of one into two. Gemination has a bifid crown and usually a common root and root canal, on the other hand fusion is a union of two teeth, normally with separated tooth buds leading to the formation of a joined tooth with the confluence of dentine. [8] It has been stated by few authors that fusion results when two tooth germ develops so close together that, as they grow, they come into contact and fuse before calcification. Other researchers believe that physical pressure of force generated during growth causes contact between adjacent tooth germs. [9]

This paper reports a case of gemination of lateral incisor which was endodontically treated and esthetically rehabilitated with all ceramic crowns. Cone beam computed tomography (CBCT) was used to enhance the radiographic details of the root canal.

   Case report Top

The present case report is about a 15-year-old male patient who reported to the post graduate clinic of the Department of Conservative Dentistry and Endodontics with the chief complaint of esthetic problem in the upper front teeth. The patient's medical history was unremarkable. Clinically, there were two crowns in the right lateral incisor with one crown in buccal relation to the other. There was a buccal groove separating the two crowns. Periodontal probing around the tooth and mobility were within physiological limits. Thermal testing (heated Gutta-percha and dry ice) and electric pulp testing (Parkel Electronics Division, Farmingdale, NY) showed a vital response. Pre-operative radiographs revealed two separate roots and root canals with joining of the canals in the apical level [Figure 1]. Counting the number of teeth a diagnosis of gemination was made, however differential diagnosis of fusion could not be ruled out. Root canal treatment followed by all ceramic crown was planned for the patient.
Figure 1: Intra oral periapical showing two root and root canals with joining of the canals in the apical level

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Local anesthesia was induced using 1.8 mL 2% lidocaine with 1:200,000 epinephrines (Xylocaine; AstraZeneca Pharma. Ind. Ltd. Bangalore, India). A rubber dam was placed and a conventional endodontic access opening was established with an Endo Access bur and an Endo Z bur (Dentsply Tulsa, Tulsa, OK). Coronal enlargement was performed with a nickel-titanium ProTaper SX rotary file (Dentsply Maillefer, Ballaigues, Switzerland) to improve the straight-line access. Root canals were explored with International Organization for Standardization #15 K-files into both the canal orifices. Interestingly both the files met at the same orifice [Figure 2]. This seemed contradictory to our initial intra oral periapical findings. Hence we planned for a CBCT after temporizing the tooth with calcium hydroxide and temporary endodontic restorative material. Informed consent was obtained from the patient and a CBCT scan was performed with a CBCT scanner (Kodak 9500 Cone Beam 3D system, Carestream Health Inc., Rochester, NY, USA) at a tube voltage of 60 kVp, tube current of 5 mA, 0.076 mm voxel resolution and the field of view of diameter 50 (limited CBCT). All protective measures were taken to protect the patient from radiation according to As Low As Reasonably Achievable guidelines. [10] Axial images were transmitted to a commercially available dental program (Kodak Dental Imaging Software 3D module v 2.4) to reformat panoramic and cross-sectional images in all three planes. Axial slices of the maxilla of 200-mm thickness were obtained at different levels to determine the root canal morphology. A 3D reconstructed image was also obtained [Figure 3] and [Figure 4]. The cross sectional CBCT images showed two canals fusing into one at the apical region [Figure 3]. This was further confirmed with axial view images [Figure 4] and [Figure 5]. At the next appointment after 1 week, after administering 1.8 mL 2% lidocaine with 1:200,000 epinephrine, the working lengths were determined with the help of an apex locator (Root ZX; Morita, Tokyo, Japan) under rubber dam isolation. Cleaning and shaping were performed using ProTaper nickel-titanium rotary instruments (Dentsply Maillefer) with a crown-down technique. During root canal preparation, irrigation was performed using normal saline, 2.5% sodium hypochlorite solution and 17% ethylenediaminetetraacetic acid. Final rinsing of the canals was performed using 2% chlorhexidine digluconate. The canals were dried with absorbent points (Dentsply Maillefer) and obturation was performed using cold lateral compaction of gutta-percha (Dentsply Maillefer) and AH Plus resin sealer (Maillefer Dentsply, Konstanz, Germany). A final radiograph was taken to establish the quality of the obturation [Figure 6]. After completion of root canal treatment, the tooth was restored with a posterior composite filling (Z100; 3M ESPE Dental Products, St Paul, MN). Crown preparation was done in the same appointment and an all ceramic crown was placed.
Figure 2: Root canals were explored with International Organization for Standardization #15 K-fi les into both the canal orifi ces

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Figure 3: The cross sectional cone beam computed tomography images showed two canals fusing into one at the apical region

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Figure 4: Axial cone beam computed tomography image at the cement enamel junction showing two coronal openings

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Figure 5: Axial cone beam computed tomography image 5 mm from apical region showing single apical opening

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Figure 6: Post obturation photograph

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   Discussion Top

The terminology dental fusion and gemination are used to define two different morphological dental anomalies, characterized by the formation of a clinically wide tooth. The main periodontal complication in gemination cases occurs due to the presence of fissures or grooves in the union between the teeth involved. If these defects are very deep and extend sub gingivally, the possibility of plaque accumulation in these area is quite high. Furthermore, gemination, may have an adverse effect on occlusion, causing deviation and sometimes delaying the eruption of other teeth with esthetic problems. In this case, despite the buccal groove in the maxillary lateral incisor, no serious periodontal breakdown was evident.

Clinically, it may be difficult to differentiate between fusion and gemination when a supernumerary tooth is fused with a permanent tooth. A full complement of teeth indicates gemination, whilst one tooth less than normal indicates fusion. [11] Generally geminated teeth have a single large pulp chamber and a root canal, as in the present case, Tomazinho et al. [12] in their study have reported a geminated tooth with a single large pulp chamber and a mesial and distal root canals that were joined at the apical third. A prerequisite for endodontic treatment of anomalous teeth is a careful examination of radiographs from various angles. The amount of information gained from conventional film is limited by the fact that the 3D anatomy of the area being radiographed is compressed into a two dimensional image. As a result of superimposition, periapical radiograph reveal limited aspects of the 3D anatomy. In addition, there may also be geometrical distortion of the anatomic structures being imaged. [13] In this case, the root canal morphology was confirmed with the help of CBCT. Complex internal anatomy has stressed the importance of root canal morphology before starting endodontic treatment. CBCT images provide a better understanding of root canal anatomy, enabling the clinician to investigate the root canal system and to clean, shape and to obturate more efficiently. [14],[15]

Radiographs have innumerable shortcomings, questioning its reliability. Recent imaging tools like spiral computed tomography and CBCT have emerged as valuable tools in the field of endodontics due to its accuracy, reliability and 3D imaging capabilities. In CBCT, a cone shaped beam rotates 360° around the patient to obtain a volume and capture the image in the form of three-dimensional isotropic voxels. These multiple voxels are further combined with the help of viewing software and a 3D image is reconstructed. [14] Its use in endodontics include identifying dental anatomic variations such as additional roots or canals, fused roots, identification of horizontal/vertical fracture line in the tooth root, management of internal and external resorptive defects [16] and identification of the configuration of inferior alveolar canal. [17] Detailed analysis of the 3D reconstruction image at the cervical, middle and apical regions of the root helped to know internal anatomy precisely. In this case, intraoral periapical intra oral-radiograph showed two separate canals, but after biomechanical preparation the canals seemed to join at the apical third of the root. So to confirm this CBCT was taken.

   Conclusion Top

Primary complaint of gemination is esthetics, so such cases should be treated with high patient satisfaction. Proper diagnosis and treatment planning ensures predictable and successful results. This paper demonstrates a predictable and successful solution toward the endodontic management of a geminated maxillary lateral incisor. It also emphasizes on how CBCT facilitates diagnosis and influences treatment. Although CBCT is a valuable adjunct which aids in diagnosis and treatment planning, conventional intraoral periapical radiographs still continue to be used in routine clinical practice due to accessibility, financial and dose considerations.

   References Top

1.Dexton AJ, Arundas D, Rameshkumar M, Shoba K. Retreatodontics in maxillary lateral incisor with supernumerary root. J Conserv Dent 2011;14:322-4.  Back to cited text no. 1
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2.Aguiló 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.  Back to cited text no. 2
3.Järvinen S, Lehtinen L, Milén A. Epidemiologic study of joined primary teeth in Finnish children. Community Dent Oral Epidemiol 1980;8:201-2.  Back to cited text no. 3
4.O Carroll MK. Fusion and gemination in alternate dentitions. Oral Surg Oral Med Oral Pathol 1990;69:655.  Back to cited text no. 4
5.Duncan WK, Helpin ML. Bilateral fusion and gemination: A literature analysis and case report. Oral Surg Oral Med Oral Pathol 1987;64:82-7.  Back to cited text no. 5
6.Altug-Atac AT, Erdem D. Prevalence and distribution of dental anomalies in orthodontic patients. Am J Orthod Dentofacial Orthop 2007;131:510-4.  Back to cited text no. 6
7.Maibaum WW. Fusion of confusion? Oral Surg Oral Med Oral Pathol 1990;69:656-7.  Back to cited text no. 7
8.Neville BW, Damm DD, Allen CM, Bouquot JE, Abnormalities of teeth. Oral and Maxillofacial Pathology. 2 nd ed. Philadelphia, PA: WB Saunders; 2002. p. 74-5.  Back to cited text no. 8
9.Joshi V, Pavankumar K, Ramana V, Joshi S, Saritha M. Bilateral fusion of mandibular primary incisors: A case report. Int J Oral Maxillofac Pathol 2011;2:40-3.  Back to cited text no. 9
10.National Council on Radiation Protection and Measurements. Radiation Protection in Dentistry. Report No. 145. Bethesda, MD: NRCP Publications; 2003.  Back to cited text no. 10
11.Aryanpour S, Bercy P, Van Nieuwenhuysen JP. Endodontic and periodontal treatments of a geminated mandibular first premolar. Int Endod J 2002;35:209-14.  Back to cited text no. 11
12.Tomazinho FS, Baratto-Filho F, Leonardi DP, Haragushiku GA, de Campos EA. Occurrence of talon cusp on a geminated maxillary central incisor: A case report. J Oral Sci 2009;51:297-300.  Back to cited text no. 12
13.Grondahland HG, Huumonen S. Radiographic manifestations of periapical inflammatory lesions. Endod Topics 2004;8:55-67.  Back to cited text no. 13
14.Chhabra N, Singbal KP, Chhabra TM. Type I canal configuration in a single rooted maxillary first molar diagnosed with an aid of cone beam computed tomographic technique: A rare case report. J Conserv Dent 2013;16:385-7.  Back to cited text no. 14
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16.Kothari HJ, Kumar R. Endodontic management of a mandibular second premolar with perforating internal resorption by using MTA and cone beam computed tomography as a diagnostic aid. J Conserv Dent 2013;16:380-4.  Back to cited text no. 16
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17.Nair UP, Yazdi MH, Nayar GM, Parry H, Katkar RA, Nair MK. Configuration of the inferior alveolar canal as detected by cone beam computed tomography. J Conserv Dent 2013;16:518-21.  Back to cited text no. 17
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Correspondence Address:
Dexton Antony Johns
Department of Conservative Dentistry, Government Dental College, Calicut - 673 008, Kerala
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0972-0707.131810

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]


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