Journal of Orofacial Sciences

: 2013  |  Volume : 5  |  Issue : 1  |  Page : 47--49

Endodontic management of supernumerary tooth fused with maxillary second molar

K Sathya Narayanan 
 Department of Conservative Dentistry and Endodontics, Sathyabama University Dental College and Hospital, Jeppiar Nagar, Chennai, Tamil Nadu, India

Correspondence Address:
K Sathya Narayanan
No: 196/138, Choolaimedu High Road, Choolaimedu, Chennai - 600 094, Tamil Nadu


Fusion is a rare occurrence, and its definitive diagnosis is of prime importance for successful root canal treatment. This case report discusses the endodontic management of a supernumerary tooth fused with a right maxillary second molar. After 1 year of follow-up, there were no clinical symptoms and the maxillary second molar remained vital. Recall radiographs appeared normal.

How to cite this article:
Narayanan K S. Endodontic management of supernumerary tooth fused with maxillary second molar.J Orofac Sci 2013;5:47-49

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Narayanan K S. Endodontic management of supernumerary tooth fused with maxillary second molar. J Orofac Sci [serial online] 2013 [cited 2021 May 8 ];5:47-49
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Supernumerary teeth are defined as those in addition to the normal series of deciduous or permanent dentition. They may occur anywhere in the mouth. They may appear as a single tooth or multiple teeth, unilaterally or bilaterally, erupted or impacted and in mandible/maxilla or both the jaws. The prevalence of supernumerary teeth varies between 0.1% and 3.8% and is more common in the permanent dentition. [1],[2],[3] The incidence is considerably higher in the maxillary incisor region followed by maxillary third molar and mandibular molar, premolar, canine and lateral incisors. [4] Though there is no significant sex distribution in primary supernumerary teeth, males are affected approximately twice than females in the permanent dentition. [5],[6]

Fusion (synodontia or false gemination) is defined as the union of two or more separately developing tooth germs at the dentinal level, yielding a single large tooth during odontogenesis, when the crown is not yet mineralized. [7],[8] The prevalence of tooth fusion is estimated to be 0.5%-2.5% in primary dentition, [9] whereas in permanent dentition, the prevalence is even lower. [10] When fusion takes place between a normal tooth and a supernumerary tooth, the fused teeth show an anomalous broad crown that might appear to be molten together with a small groove between them. [10] The pulp chambers and root canals might be joined or separated, depending on the stage of development at the time of union. [11]

This article reports a rare case of fusion between a maxillary second molar and a supernumerary tooth, where endodontic treatment of the supernumerary tooth and the restoration of this tooth complex maintained pulp vitality of the maxillary second molar.

 Case Report

A 24-year old male patient complained of spontaneous, intermittent throbbing pain in the maxillary right molar area. The patient's medical history was non-contributory. Clinical examination revealed a large extra cusp on the buccal aspect of the right maxillary second molar (tooth #-17) [Figure 1]. Distinct developmental occlusogingival grooves between the supernumerary tooth and its normal counterpart were noticed. Despite the presence of the grooves, there was no discernible separation between the two teeth. The fusion between the buccal aspect of the tooth #-17 and the supernumerary tooth resulted in increased buccolingual width with a wide distinct crown. A carious lesion was detected on the supernumerary tooth. The right maxillary second molar showed normal responses to cold and electric pulp tester. No mobility was noted, and the tooth was not tender to percussion. Pre-operative radiograph revealed fusion between the right maxillary second molar and the supernumerary tooth [Figure 2].{Figure 1}{Figure 2}

A diagnosis of chronic apical periodontitis of the supernumerary tooth was made on the basis of the clinical and radiographic findings. The pulp and periodontal tissue of the right maxillary second molar was determined to be normal. The tooth was isolated with a rubber dam, the pulp chamber of the supernumerary tooth was exposed, and one central canal was instrumented. The right maxillary second molar showed a normal response to thermal, electrical, and percussion stimuli, so we decided to perform root canal treatment for the supernumerary tooth only. The working length was determined by using an apex locator (Root ZX; Morita, Tokyo, Japan), followed by confirmation with a radiograph [Figure 3]. However, by exploring the pulp chamber of the supernumerary tooth by using a curved file combined with an electronic apex locator provided no evidence of communication between the two pulp canal systems. The root canal of the supernumerary tooth was cleaned and shaped with ProTaper (Dentsply-Maillefer, Ballaigues, Switzerland) rotary instruments under copious irrigation with 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid. Then the access cavity was restored with temporary sealing material (Caviton; GC, Tokyo, Japan). One week later, the patient was asymptomatic, and the root canal was dried and obturated with ProTaper gutta-percha and AH Plus sealer (Dentsply-DeTrey, Konstanz, Germany) [Figure 4]. Then the access cavity was restored permanently with a universal composite resin restorative material (Z250; 3M).{Figure 3}{Figure 4}

After 1 year of follow-up, there were no clinical symptoms, and the right maxillary second molar remained vital. Recall radiographs appeared normal [Figure 5].{Figure 5}


Supernumerary teeth can be classified according to chronology, location (topography), morphology and their orientation. Chronologically, they can be classified as pre-deciduous, similar to permanent teeth, and post-permanent or complementary; morphologically as conical, tuberculate, supplemental (eumorphic) and odontome; topographically as mesiodens, paramolar, distomolar and parapremolar, and according to orientation as vertical, inverted and transverse. [12] The exact etiology of the supernumerary teeth has not yet completely understood. Several theories have been suggested for their occurrence, such as the phylogenetic theory [13] the dichotomy theory [14] occurrence due to hyperactive dental lamina [15] and due to a combination of genetic and environmental factors. [16]

Fusion of molar teeth with supernumerary teeth is particularly rare, but when it does occurs, it commonly results in caries, periodontal disease, and crowding. Since grooves created by the union between the teeth involved are deep, bacterial plaque accumulates readily in this area. Endodontic treatment is usually problematic, owing to the complex anatomy, tooth positioning, and difficulty in rubber dam isolation. [17] Delany and goldblatt [18] and Hulsmann [10] reported that most fusions necessitate surgical removal of the involved teeth because of their abnormal morphology and excessive mesio distal width, causing crowding, tooth malalignment and occlusal dysfunction.

In the present case the caries had not extended into the maxillary second molar pulp chamber and only the supernumerary tooth pulp was exposed.

However, before concluding that the canals were independent, careful screening is essential. Diagnostic tools such as multiple radiographs, cone-beam computed tomography, careful examination of the root canal with a curved file, and better visualization by using an operating microscope are all important aids in detecting communication.


In the present case, successful nonsurgical endodontic treatment of the supernumerary tooth fused with a maxillary second molar was performed. Clinicians should consider the pulp vitality of the supernumerary tooth and the tooth to which it is fused independently. Proper diagnosis and treatment planning for endodontic management of the fused teeth can ensure predictable and successful results.


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