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Year : 2016  |  Volume : 8  |  Issue : 2  |  Page : 135-138

Triunity of mandibular deciduous anteriors: A rarity in morphology

Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka, India

Date of Web Publication16-Dec-2016

Correspondence Address:
Dr. Indavara Eregowda Neena
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Pavilion Road, Davangere - 577 004, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0975-8844.195912

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An uncommon developmental anomaly such as a triple tooth may result from fusion, gemination, or concrescence that may occur between two and more teeth or between normal tooth and a supernumerary tooth. This anomaly may occur as a result of conjoining or twining defects that affect both primary and permanent dentition. In this article, we report an unusual case of triplication of primary teeth occurring unilaterally between the lower left lateral incisor and the canine, where the lateral incisor is geminated and it is fused to the canine. The triple tooth was extracted under local anesthesia and its crown portion was sectioned at three levels that are coronal, middle, and cervical one-third, respectively, following which, the sections were observed under a stereomicroscope. Based on the clinical and histologic findings, final diagnosis of gemination of lateral incisor with fusion to the canine is confirmed.

Keywords: Anomalies, fusion, gemination, primary teeth, triple tooth

How to cite this article:
Mallikarjun K, Poornima P, Neena IE, Meharwade P. Triunity of mandibular deciduous anteriors: A rarity in morphology. J Orofac Sci 2016;8:135-8

How to cite this URL:
Mallikarjun K, Poornima P, Neena IE, Meharwade P. Triunity of mandibular deciduous anteriors: A rarity in morphology. J Orofac Sci [serial online] 2016 [cited 2023 Jun 9];8:135-8. Available from:

  Introduction Top

Developmental disturbances of teeth can be classified based on number, size, shape, and structure.[1] Triplication of teeth is described as rare dental anomaly where three primary teeth appear to be joined.[2] Shafer, Hine, and Levy classified the conditions resulting into this abnormality:

  1. Fusion — Arises as a result of union of two or more normal tooth germs (synodontia) or between a normal tooth and a supernumerary tooth.
  2. Gemination — Arises as a result from an attempt at division of a single tooth germ (shizodontia) resulting in incomplete formation of two teeth.
  3. Concrescence — Is a form of fusion that occurs after root formation is completed and the teeth are united by cementum only.[3]

The possible cause of such anomaly maybe due to some physical force or pressure between the adjacent tooth germs, genetics, trauma, environmental influences, systemic disease, and lack of space in dental arch.[4] The phenomenon of triple tooth is rare with a prevalence of 0.02%.[1] This condition may occur unilaterally or bilaterally in either the maxilla or the mandible and more commonly seen in the incisor and the canine region in deciduous dentition. Problems associated with this condition include esthetics, caries, and malocclusion, in addition to retardation or alteration of the development of permanent teeth.[5]

This case report describes a rare case of gemination of mandibular left lateral incisor along with fusion to the left canine in a 9-year-old boy.

  Case Report Top

A 9-year-old male patient reported to the Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka, India with a chief complaint of pain in the lower right back region of the jaw since 2 days. The pain was mild, nonradiating in nature, with no aggravating or relieving factors. Medical history and family history was not significant and no abnormality was detected on extraoral examination.

Intraoral examination revealed that the patient was in a mixed dentition phase with proximal caries on the distal side of the lower right first molar, occlusal caries on the lower right and second left molar. Accidentally, we found a large tooth in the lower left anterior region that showed fusion between central, lateral incisor, and canine associated with grade I mobility. Permanent central and lateral incisors had already erupted. Intraoral periapical radiograph along with digital radiograph was taken that revealed gemination of the lateral incisor along with fusion to canine and resorption of the roots on the mesial side [Figure 1] and [Figure 2]. The remaining primary teeth in both the arches were normal along with other permanent teeth being in various stages of development.
Figure 1: Intraoral photograph of left lateral view showing triple teeth

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Figure 2: Intraoral periapical radiograph depicting triple teeth

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The treatment that was carried out includes restoration of all the carious teeth followed by extraction of the triple tooth [Figure 3]. For histologic examination, the crown part of the triple tooth was sectioned by using diamond disk at three levels: The coronal, middle, and cervical levels, respectively, and the root was divided into two parts. These sections were then visualized under stereomicroscope at a magnification of 50x. Based on the findings, a final diagnosis of gemination of the lateral incisor along with fusion to the canine was confirmed.
Figure 3: Extracted triple teeth

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  Discussion Top

A rare case of gemination-combined fusion occurring unilaterally between mandibular left lateral incisor and canine has been reported. This phenomenon of triplication of primary teeth is rare and is seldom reported.[6] The first description of triple tooth was given by Bennet in the late 1880s; since then, quite a few cases have been reported in medical literature. So far, only three cases of triplication of primary teeth occurring on the left side of the mandible has been reported by Fukushima in 1932, Long in 1951, and Kurso et al. in 1968.[1]

Yuen suggests that this phenomenon is more common in the Mongolian race.[6] There exists a clear racial difference in the incidence of fused primary teeth between Caucasians and Asians with highest incidence occurring in Japanese people.[7] This condition is more common in boys as compared to girls. The age varies from 1 year 11 months to 10 years, with a mean age of 4.9 years. It is more common in the maxilla than in the mandible, more predominance seen on the left side compared to the right side, occurring in both deciduous and permanent dentition.[1]

Several terms have been used to describe these anomalies such as gemination, fusion, concrescence, double teeth, and conjoined teeth.[8] Gemination is defined as where a single tooth bud has attempted to divide, resulting in a tooth with a single root and a large bifid crown. Fusion occurs when two/more tooth germs form one single tooth with two pulp chambers and their respective root canals. Depending on the stage at which the union occurs, it may be complete fusion or incomplete fusion.[9] If fusion occurs before the calcification stage, the teeth may unite completely to form one large tooth. If fusion occurs after crown completion, there may be an union of roots only. In complete fusion, we usually see one pulp chamber and one root canal, but in incomplete fusion, there are two individual root canals or two pulp chambers.[4] Distinction between fusion and gemination is made on the basis of dental formula. Because the geminated tooth occurs as a single large tooth and when this tooth is counted as one, the tooth count remains normal, whereas in fusion, if the fused tooth is counted as one, then the tooth count is less than the normal count.[3]

Histological examination revealed coronal and middle one-third of the crown portion showing three separate pulp chambers and a continuous layer of dentin whereas in cervical one-third of the crown portion we can appreciate a single separate pulp chamber and joining of the other two pulp chambers. The root portion was divided into two parts and both the sections when observed under stereomicroscope showed one single separate canal and two joined canals along with a continuous layer of cementum. These findings showed that there is gemination of the lateral incisor along with fusion to the canine [Figure 4], [Figure 5], [Figure 6], [Figure 7].
Figure 4: Stereomicroscopic view of incisal 1/rd of crown showing gemination along with fusion

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Figure 5: Stereomicroscopic view of middle 1/3rd of crown showing gemination along with fusion

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Figure 6: Stereomicroscopic view of cervical 1/3rd of crown showing gemination along with fusion

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Figure 7: Stereomicroscopic view of root portion showing gemination along with fusion

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Fused teeth are usually asymptomatic, hence, anomalies in the primary dentition are underestimated.[4] However, the presence of these anomalies are associated with a higher risk of anomalies in permanent dentition, especially hypodontia.[5] The clinical problems associated with these conditions are delayed eruption, displacement or rotation of permanent successors, crowding, dilacerations, and root resorption of adjacent teeth in permanent dentition.[3]

Thus, a radiographic examination should be carried out in every case and the subsequent treatment of the fused teeth depends upon clinical situation.[5] As in this case, permanent successors had already erupted and the fused tooth was mobile, hence, extraction of the fused teeth was carried out under local anesthesia.

  Conclusion Top

Fused teeth are rarely seen in children, but when they are present, they pose many problems such as esthetic and functional problems. Hence, it is impertinent that the pedodontist identifies these conditions at an early stage with proper clinical examination, followed by radiographic and histological evaluation and suitable treatment for the particular clinical situation must be carried out as soon as possible.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Shilpa G, Nuvvula S. Triple tooth in primary dentition: A proposed classification. Contemp Clin Dent 2013;4:263-7.  Back to cited text no. 1
[PUBMED]  Medknow Journal  
Aguilo L, Catala M, Peydro A. Primary triple teeth: Histological and CT morphological study of two case reports. J Clin Pediatr Dent 2001;26:87-92.  Back to cited text no. 2
Mohapatra A, Prabhakar AR, Raju OS. An unusual triplication of primary teeth — A rare case report. Quintessence Int 2010;41:815-20.  Back to cited text no. 3
Rao A. Synodontia of deciduous maxillary central and lateral incisors with a supernumerary tooth. J Indian Soc Pedo Prev Dent 2000;18:71-4.  Back to cited text no. 4
Yadav S, Tyagi S, Kumar P, Sharma D. Triplication of deciduous teeth: A rare dental anomaly. Niger J Surg 2013;19:85-7.  Back to cited text no. 5
[PUBMED]  Medknow Journal  
Schultz-Weidner N, Ansari F, Mueller-Lessmann V, Wetzel WE. Bilateral triplicated primary central incisors: Clinical course and therapy. Quintessence Int 2007;38:395-9.  Back to cited text no. 6
Mochizuki K, Yonezu T, Yakushiji M, Machida Y. The fusion of three primary incisors: Report of case. ASDC J Dent Child 1999; 66:421-5, 367.  Back to cited text no. 7
Erdem GB, Uzamiş M, Olmez S, Sargon MF. Primary incisor triplication defect. ASDC J Dent Child 2001;68:322-5, 301.  Back to cited text no. 8
Shafer WG, Hine MK, Levy BM. A Text Book of Oral Pathology. 3rd ed. Philadelphia: WB Saunders; 1974. p. 3746.  Back to cited text no. 9


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]

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