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 Table of Contents  
Year : 2022  |  Volume : 34  |  Issue : 2  |  Page : 137-140

Management of an anomalous maxillary lateral incisor fused with a supernumerary tooth and a coronal dens invaginatus

1 Department of Conservative Dentistry and Endodontics, RUHS College of Dental Sciences, Jaipur, Rajasthan, India
2 Department of Conservative Dentistry and Endodontics, Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan, India
3 Department of Oral Pathology and Microbiology, Daswani Dental College and Research Centre, Kota, Rajasthan, India
4 Department of Conservative Dentistry and Endodontics, Asan Memorial Dental College, Chengalpattu, Tamil Nadu, India

Date of Submission24-Oct-2021
Date of Decision03-Jan-2022
Date of Acceptance01-Apr-2022
Date of Web Publication01-Jul-2022

Correspondence Address:
Dr. Lalit Kumar Likhyani
Department of Conservative Dentistry and Endodontics, RUHS College of Dental Sciences, Subhash Nagar, Jaipur - 302 016, Rajasthan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/endo.endo_197_21

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An abnormal union of two or more tooth germs in the development process results in fusion of teeth. Such clinical situations present a diagnostic dilemma and a challenge in treatment planning. This article reports the endodontic and esthetic management of an atypical permanent maxillary lateral incisor fused with a supernumerary tooth and a coronal dens invaginatus. A 22-year-old female reported an abnormally large and discolored permanent maxillary left lateral incisor (#22). Cone-beam computed tomographic evaluation revealed a complex, labiolingually thin ribbon-shaped canal system in the central portion interconnected with two other canals along with a coronal dens invaginatus. A 2-year follow-up demonstrated satisfactory clinical and radiographic outcomes after the endodontic therapy and a veneer placement on the concerned tooth.

Keywords: Cone-beam computed tomography, dens invaginatus, incisor, supernumerary, tooth abnormalities

How to cite this article:
Likhyani LK, Choudhary M, Khandelwal S, Chacko Y. Management of an anomalous maxillary lateral incisor fused with a supernumerary tooth and a coronal dens invaginatus. Endodontology 2022;34:137-40

How to cite this URL:
Likhyani LK, Choudhary M, Khandelwal S, Chacko Y. Management of an anomalous maxillary lateral incisor fused with a supernumerary tooth and a coronal dens invaginatus. Endodontology [serial online] 2022 [cited 2022 Aug 8];34:137-40. Available from: https://www.endodontologyonweb.org/text.asp?2022/34/2/137/349566

  Introduction Top

Fusion is a developmental dental anomaly of shape, form, or morphology that occurs when two or more developing tooth germs unite at the dentinal level, yielding a single large tooth.[1] Some physical force or pressure, trauma, inflammation, or local metabolic interferences during tooth bud differentiation may lead to the fusion of two tooth buds. As a result, the dental count decreases in fusion. Gemination is a similar dental anomaly that demonstrates two crowns or one large, partially separated crown, usually sharing a single root or root canal. The dental count is normal in gemination.[2]

The incidence of gemination and fusion is more in the primary dentition, particularly in the incisor–canine region. The incidence of fused teeth is about 0.5% and 0.1% in primary and permanent dentition, respectively.[3],[4]

Dens invaginatus results from the invagination of the enamel organ into the dental papilla before the calcification stage. As per Oehlers classification of dens invaginatus, the Type I category includes an enamel-lined minor form occurring within the crown not extending beyond the cementoenamel junction. The most frequently affected teeth are permanent maxillary lateral incisors.[1],[5]

We report management of a rare case of a permanent maxillary lateral incisor fused with a supernumerary tooth and a Type I dens invaginatus.

  Case Report Top

A 22-year-old female reported a chief complaint of an abnormally large and discolored upper left front tooth. Dental, medical, drug, and family history were insignificant. Intraoral evaluation revealed a dark yellow-colored permanent maxillary left lateral incisors (tooth #22), with an abnormal mesiodistal diameter and uneven corrugated labial surface [Figure 1]a. A deep invagination was evident distally on the palatal surface [Figure 1]b. The dental count was normal. The periodontal status of the tooth appeared satisfactory based on palpation and percussion tests. Cold testing elicited a negative response. The intraoral periapical radiograph [Figure 2]a revealed a mature bulbous lateral incisor with two separate enamel-like radiopaque crown portions and a small sac-shaped invagination confined to the crown portion distally. The radiograph also revealed a single sizeable root with a possibility of multiple canals, including a canal of dens invaginatus. In addition, a periapical radiolucency concerning tooth #22 was evident. Based on the above findings, we diagnosed tooth #22 associated anomaly as the fusion of a regular tooth bud with a supernumerary tooth bud and a Type I dens invaginatus. The anomalous tooth was associated with pulpal necrosis and asymptomatic apical periodontitis. We planned for a nonsurgical root canal treatment followed by an all-ceramic veneer to ensure pleasing esthetics.
Figure 1: (a and b) Preoperative photograph showing labial and palatal view (tooth #22). (c and d) Intraoperative photograph showing septa in the main canal (red arrow) and a separate opening for the dens invaginatus (blue arrow). (e) Photograph after obturation. (f and g) Postoperative photograph: labial and palatal view revealing esthetic rehabilitation

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Figure 2: (a) Preoperative radiograph (tooth #22). (b) Intraoperative radiograph. (c) Working length radiograph. (d) Master cone radiograph. (e) Postoperative radiograph. (f) A 2-year follow-up radiograph

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After taking informed consent, two separate access openings were prepared for the central canal and the dens under dental dam isolation [Figure 1]c and [Figure 1]d. While instrumenting the central canal, we realized that it had dentinal septa inside [Figure 1]c, giving a feel of multiple canals. A closed dressing without any medicament was provided [Figure 2]b, and the patient was advised for a cone-beam computed tomographic (CBCT) scan.

CBCT (Carestream CS 9300 imaging systems; Carestream Health, Inc., New York, USA) evaluation revealed a labiolingually thin ribbon-shaped canal system in the central portion along with two other canals. These three canals had connections throughout the entire length of the root [Figure 3]a, [Figure 3]b, [Figure 3]c, [Figure 3]d. A coronal dens invaginatus (Type I) was also evident in the distal portion of the crown [Figure 3]a and [Figure 3]b. In addition, periapical bone destruction was noticed toward the palatal aspect of the apical third of the root [Figure 3]e and [Figure 3]f.
Figure 3: Cone-beam computed tomography serial axial sections concerning tooth #22: (a and b) Coronal one third. (c and d) Middle one third. (e and f) Apical one third. (Yellow arrow) Type I dens invaginatus in the distal portion of the crown. (Red arrows) A labiolingually thin ribbon-shaped canal system in the central portion along with interconnected two canals. (White arrow) Periapical bone destruction around the apical third of the root

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A working length radiograph confirmed a complex canal system [Figure 2]c. The canals were shaped to the size ProTaper Next X3 file (Dentsply Maillefer, Switzerland) under copious irrigation with 5.25% sodium hypochlorite. The canal of the dens portion was shaped to K-file size 40/02 (Mani Inc., Tochigi, Japan). A master cone radiograph revealed five canals in total [Figure 2]d. Before obturation, 5.25% sodium hypochlorite was activated using endoactivator (Dentsply Maillefer, Switzerland) followed by 1 ml of 17% ethylene diamine tetra-acetic acid solution to achieve adequate debridement of complex pulp spaces.[6] After drying with paper points, the canal system was obturated using AH Plus Sealer (Dentsply Maillefer, Switzerland) and a warm vertical compaction technique [Figure 1]e. The access cavity was restored using a universal composite resin [Figure 2]d and [Figure 2]e.

The second phase consisted of esthetic rehabilitation to correct the excessive mesiodistal width and discoloration. A lithium di-silicate (E-Max, Ivoclar Vivadent AG, Liechtenstein) veneer with some changes in the line angles, darker shade, and gingival ceramic on the distal half of the veneer created an illusion of a narrow tooth [Figure 1]f and [Figure 1]g.

A 2-year follow-up demonstrated satisfactory clinical and radiographic outcomes [Figure 2]f.

  Discussion Top

The dental formula makes the clinical diagnosis of fusion and gemination. It is challenging and sometimes impossible to differentiate fusion and gemination when the supernumerary tooth bud unites with the adjacent normal one.[7] In such situations, a radiographic examination and a CBCT evaluation are necessary to obtain a correct diagnosis. Dentinal union is always there in cases of true fusion, which can vary from partial to complete fusion of both roots and crowns. Consequently, pulp chambers may be separated or common to both fused teeth. In some instances, the pulp chamber may be continuous with one wide and single root canal, but sometimes, the root canals may be completely separated.[2]

In the present case, the dental count was normal in the maxillary arch after considering the fused tooth as one unit, and it is possible only when there is a fusion of the lateral incisor with a supernumerary tooth bud.

Fused teeth can be associated with various clinical manifestations such as poor esthetics, higher degree of caries, and periodontal problems due to the deep grooves present in the tooth.[7] A CBCT scan in such cases provides accurate three-dimensional information and helps in optimum treatment planning.[8] The treatment depends on the patient's requirement, the teeth involved, and the degree of involvement. Fusion and gemination may require a multidisciplinary approach to restore the function and esthetics.[7],[9]

  Conclusion Top

A combination of fusion anomaly and dens invaginatus can create challenges in the management at multiple levels. Therefore, a comprehensive treatment plan utilizing all the technological advancements is necessary for successful treatment outcomes in such cases.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Ahmed HM, Dummer PM. A new system for classifying tooth, root and canal anomalies. Int Endod J 2018;51:389-404.  Back to cited text no. 1
Tannenbaum KA, Alling EE. Anomalous tooth development. Case reports of gemination and twinning. Oral Surg Oral Med Oral Pathol 1963;16:883-7.  Back to cited text no. 2
Tasa GL, Lukacs JR. The prevalence and expression of primary double teeth in western India. ASDC J Dent Child 2001;68:196-200.  Back to cited text no. 3
Tomizawa M, Shimizu A, Hayashi S, Noda T. Bilateral maxillary fused primary incisors accompanied by succedaneous supernumerary teeth: Report of a case. Int J Paediatr Dent 2002;12:223-7.  Back to cited text no. 4
Hülsmann M. Dens invaginatus: Aetiology, classification, prevalence, diagnosis, and treatment considerations. Int Endod J 1997;30:79-90.  Back to cited text no. 5
Wang Z, Maezono H, Shen Y, Haapasalo M. Evaluation of root canal dentin erosion after different irrigation methods using energy-dispersive X-ray spectroscopy. J Endod 2016;42:1834-9.  Back to cited text no. 6
Sivolella S, Bressan E, Mirabal V, Stellini E, Berengo M. Extraoral endodontic treatment, odontotomy and intentional replantation of a double maxillary lateral permanent incisor: Case report and 6-year follow-up. Int Endod J 2008;41:538-46.  Back to cited text no. 7
Patel S, Brown J, Semper M, Abella F, Mannocci F. European Society of Endodontology position statement: Use of cone beam computed tomography in Endodontics: European Society of Endodontology (ESE) developed by. Int Endod J 2019;52:1675-8.  Back to cited text no. 8
Oelgiesser D, Zyc R, Evron D, Kaplansky G, Levin L. Treatment of a fused/geminated tooth: A multidisciplinary conservative approach. Quintessence Int 2013;44:531-3.  Back to cited text no. 9


  [Figure 1], [Figure 2], [Figure 3]


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