Archives of Medicine and Health Sciences

: 2015  |  Volume : 3  |  Issue : 1  |  Page : 85--87

Fusion of deciduous central incisors

Imran Mohtesham, Moidin Shakil, Maji Jose, Vishnudas Prabhu 
 Department of Oral Pathology and Microbiology, Yenepoya Dental College, Yenepoya University, Mangalore, Karnataka, India

Correspondence Address:
Dr. Moidin Shakil
Department of Oral Pathology and Microbiology, Yenepoya Dental College, Yenepoya University, Mangalore - 575 018, Karnataka


Fusion is a common dental anomaly affecting both primary as well permanent dentitions. Fusion is the union between two normally separated tooth germs. The problems associated with fused teeth are esthetics, arch symmetry, spacing, and malocclusion. These problems require cosmetic and orthodontic consideration.

How to cite this article:
Mohtesham I, Shakil M, Jose M, Prabhu V. Fusion of deciduous central incisors.Arch Med Health Sci 2015;3:85-87

How to cite this URL:
Mohtesham I, Shakil M, Jose M, Prabhu V. Fusion of deciduous central incisors. Arch Med Health Sci [serial online] 2015 [cited 2020 Apr 1 ];3:85-87
Available from:

Full Text


Various terms have been used to describe fusion and gemination of teeth such as double tooth, joined teeth or connoted teeth. Both fusion and gemination are developmental anomalies of the teeth. [1] Fusion of teeth is the union of two normally separated tooth germs, and it may be either complete or incomplete depending upon the stage of development of the teeth at the time of union, whereas gemination refers to incomplete division of tooth and results in a large tooth crown that has a single root and a single canal. [2],[3]

Fusion is one of the most frequent anomalies encountered in the primary dentition and often confused with gemination; [4] however a differential diagnosis can be made radiographically. Fusion can occur both in deciduous and permanent dentition but is more common in deciduous dentition. [5],[6] In primary dentition, the frequency of fusion may be about 2.5% and bilateral presentation is very rare. The etiology may be physical force or pressure leading to prolonged contact of the adjacent tooth follicle causing fusion of tooth buds. [7]

 Case Report

A 9-year-old boy reported to a private dental clinic with a complaint of delayed exfoliation of primary teeth and the patient was referred to the department of oral pathology. On intraoral examination, there was a large sized tooth in the mandibular anterior region [Figure 1]. An intraoral periapical (IOPA) was advised for the same. A diagnosis of fusion of 51 and 61 affecting the shape of teeth was made. An IOPA radiograph [Figure 2] also revealed there was a union between two teeth. Extraction of fused teeth number 51 and 61 was made to facilitate eruption of the permanent teeth [Figure 3] and [Figure 4].{Figure 1}{Figure 2}{Figure 3}{Figure 4}


The terms fusion and gemination have been used to define two different dental anomalies characterized by formation of a wide tooth. Numerous cases have been reported in the literature and yet their differential diagnosis is difficult. Case history, clinical and radiological examination can give adequate information to arrive at a proper diagnosis and to discern one entity from the other. [1] Fusion is seen in both deciduous and permanent dentition but more common in the deciduous dentition. The prevalence of fusion ranges from 0.5% to 2.5% according to the population surveyed. [8]

The etiology of fusion of the teeth is not known. It results when development of two tooth germs take place close to each other and fuse before calcification. Most of the researchers believe that the physical pressure and force generated while growth causes contact between two tooth germs. [9] Fusion can occur between normal teeth or between normal and supernumerary teeth. [1] On some occasions, two independent pulp chambers and canals can be seen. Viral infection and usage of thalidomide during pregnancy is also been implicated in its etiology. [10] Fusion of primary teeth usually is seen in mandibular canine and lateral incisor region. In contrast to this, in our case, there was a fusion between two mandibular incisors. The shape and size of the teeth are genetically determined, but any external and/or internal factors such as trauma, hormonal changes, nutritional deficiency and exposure to radiation during the development of teeth could affect the shape, size, number, and quality of dentition.

The differential diagnosis of fusion and gemination based on the number of teeth present is not always precise. [3] Since fusion may be due the union of a normal tooth bud to a supernumerary tooth germ, the number of teeth is also normal and differentiation from gemination, if not impossible, may be very difficult.

The clinical problems associated with fused teeth are esthetics, arch symmetry, spacing, and malocclusion owing to its irregular morphology. They also show a high susceptibility for caries and periodontal problems. These problems require cosmetic and orthodontic consideration.


1Pereira AJ, Fidel RA, Fidel SR. Maxillary lateral incisor with two root canals : f0 usion, gemination or dens invaginatus? Braz Dent J 2000;11:141-6.
2Chalakkal P, Thomas AM. Bilateral fusion of mandibular primary teeth. J Indian Soc Pedod Prev Dent 2009;27:108-10.
3O'Reilly PM. Structural and radiographic evaluation of four cases of tooth fusion. Aust Dent J 1990;35:226-9.
4Hagman FT. Fused primary teeth : a0 documented familial report of case. ASDC J Dent Child 1985;52:459-60.
5Ballal NV, Kundabala M, Acharya S. Esthetic management of fused carious teeth : a0 case report. J Esthet Restor Dent 2006;18:13-7.
6O Carroll MK. Fusion and gemination in alternate dentitions. Oral Surg Oral Med Oral Pathol 1990;69:655.
7Prabhu NT, Rebecca J, Munshi AK. Bilaterally fused primary mandibular incisors - A case report. J Indian Soc Pedod Prev Dent 1997;15:31-3.
8Grahnen H, Granath L. Numerical variation in primary dentition and their correlation with the permanent dentition. Odontol Revy 1961;12:248-57.
9White SC, Pharoah MJ. Oral Radiology Principles and Interpretation. 5 th ed. St. Louis: Mosby Inc.; 2004. p. 337-8.
10Kjaer I, Daugaard-Jensen J. 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.