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 Table of Contents  
CASE REPORT
Year : 2017  |  Volume : 6  |  Issue : 3  |  Page : 182-184

Bilateral fusion of mandibular primary teeth with partial anodontia of permanent teeth: A report of a rare case


1 Department of Pedodontics and Preventive Dentistry, Sharavathi Dental College and Hospital, Shivamogga, India
2 Department of Pedodontics and Preventive Dentistry, Sri Siddhartha Dental College and Hospital, Tumkur, Karnataka, India
3 Department of Orthodontics and Dentofacial Orthopedics, Sharavathi Dental College and Hospital, Shivamogga, India

Date of Web Publication6-Feb-2018

Correspondence Address:
Dr. V Rajashekar Reddy
Department of Pedodontics and Preventive Dentistry, Sharavathi Dental College and Hospital, Shivamogga, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/sjhs.sjhs_43_17

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  Abstract 

Fusion is a developmental anomaly of shape of the tooth seen in developing primary or permanent teeth. Etiology is not exactly known, but the physical pressure or force generated during growth causes contact and fusion between adjacent tooth buds. The genetic foundation for the anomaly is possibly autosomal dominant with reduced penetrance. The bilateral type of fusion in the primary dentition is very rare and is usually 0.02%. Till now, only 18 cases have been previously reported in dental literature since 1940, and in the Indian population, only few cases have been reported. In bilateral fusion of primary lateral incisor and canine, 75% chance of lacking the succedaneous lateral incisors have been reported. The anomalies of the permanent dentition are strongly associated with anomalies in the primary dentition. The potential clinical problems associated with fusion require orthodontic, prosthetic, cosmetic, and periodontal intervention also. Thus, to establish a right treatment to this anomaly, the early proper examination and knowledge to recognize the anomalies associated between primary teeth and permanent teeth is a prerequisite.

Keywords: Bilateral, congenital missing, fusion, primary teeth


How to cite this article:
Reddy V R, Chowdhary N, Kumar G S, Ambareen Z. Bilateral fusion of mandibular primary teeth with partial anodontia of permanent teeth: A report of a rare case. Saudi J Health Sci 2017;6:182-4

How to cite this URL:
Reddy V R, Chowdhary N, Kumar G S, Ambareen Z. Bilateral fusion of mandibular primary teeth with partial anodontia of permanent teeth: A report of a rare case. Saudi J Health Sci [serial online] 2017 [cited 2022 Jan 24];6:182-4. Available from: https://www.saudijhealthsci.org/text.asp?2017/6/3/182/224748


  Introduction Top


Fusion or synodontia is a developmental anomaly of shape of the tooth formed by the union of two independently developing primary or permanent teeth. The union of two separate tooth buds may be either complete or incomplete. Fused teeth have separate or shared pulp chambers and canals depending on the time of fusion. This malformation can be distinguished from gemination because it is an attempt by the tooth germ to divide.[1]

The etiology of fusion is not exactly known. Most of the researchers believe that physical pressure or force generated during growth causes contact between adjacent tooth buds. Some writers contend that fusion results when two tooth buds develop close together that, as they grow, they come into contact and fuse before calcification. Another possibility for this anomaly may be the use of thalidomide drug during pregnancy for viral infections. The genetic foundation for the anomaly is possibly autosomal dominant with reduced penetrance.[2],[3]

The prevalence of tooth fusion is estimated at 0.5%–2.5% in the primary dentition and less in permanent dentition.[4] The bilateral type of fusion in the primary dentition is very rare and is only 0.02%.[5] Till now, 18 cases have been previously reported in the dental literature between 1940–2017, and in Indian population, only few cases have been reported.[1],[5],[6],[7],[8],[9] The most common problem related to the fused primary teeth is the hypodontia of permanent teeth. Therefore, case with bilateral fused primary teeth necessitates careful examination and knowledge of the anomalies in primary dentition and its association with succeeding permanent dentition anomalies is a prerequisite for proper treatment planning. Hence, this article aimed at reporting a case of this rare condition and evaluating the anomalies of succeeding permanent teeth.


  Case Report Top


A 7-year-old boy reported to the department of pedodontics and preventive dentistry with the complaint of large irregular teeth in the lower jaw. The patient has no systemic disorders, and there were no abnormalities in his medical and family history. The patient had undergone dental treatment previously due pain in the lower left back teeth region. On intraoral examination, the patient was in early mixed dentition, there was bilaterally fused mandibular primary lateral incisor and canine, which was confirmed by counting the number of teeth present [Figure 1] and 74 had stainless steel crown. On radiographic examination, there was incomplete type of fusion bilaterally between mandibular primary lateral incisor and canine and congenital missing of mandibular permanent lateral incisor tooth buds bilaterally and pulpotomy in 74 [Figure 2].
Figure 1: Bilateral fusion of <72–73> and <82–83>

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Figure 2: Congenital missing of 32 and 42

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The case was diagnosed as bilaterally fused mandibular primary lateral incisor and canine of incomplete type with congenital missing of mandibular permanent lateral incisors.


  Discussion Top


A rare case of bilateral fusion between the primary mandibular lateral incisor and canine is presented here. Fusion can be classified into complete type and incomplete type. In the complete type, fusion begins before calcification, and the crown includes features of both participating teeth regarding their enamel, dentin, cementum, and pulp. In the incomplete type, fusion occurs at a later stage, the tooth might exhibit separate crowns and fusion may be limited to the roots alone with pulp canals fused or separate. The differential diagnosis for fused teeth includes gemination and macrodontia. Several clinical and radiographic benchmarks are used to distinguish fusion from gemination. Fusion is the incomplete attempt of two tooth buds to fuse into one; however, gemination is the incomplete attempt of one tooth bud to divide into two.[3] These two anomalies can be differentiated clinically by counting the number of teeth present.

Cho reported that double teeth involving primary canines and lateral incisors is found only in the mandible.[7] White and Pharoah reported that, when a primary canine and lateral incisor fuse, the corresponding permanent lateral incisor may be absent [8] and Hegman also reported that, such patients have a 75% chance of lacking the succedaneous lateral incisors.[10]

When fusion of primary teeth occurs, the clinician must have knowledge on anomalies associated with permanent teeth and for treatment planning, clinician must be aware of five major dental concerns. First, fused teeth are clearly wider than the surrounding teeth; esthetics may be a concern. Second, when normal teeth fuse, excess dental space can result. This occurs because two fused teeth require less space in the dental arch than two normal teeth. This can result in diastema formation.[11]

The third concern relates to both esthetics and occlusion because of missing permanent teeth. When fusion occurs in the primary dentition, some of the permanent incisors often not present. This problem requires both cosmetic and orthodontic consideration. Fourth concern is careful monitoring of delayed erupting permanent tooth. The final concerns involve their surface contour.[6],[7],[8],[10],[11],[12] Fused teeth commonly exhibit labial and lingual grooves running vertically on the crown surface. These grooves may be very pronounced, particularly in cases of incomplete fusion. Since these grooves may be difficult to clean, caries may result. The placement of fissure sealants or composite restorations in these grooves will decrease the caries risk.[13] In addition, if these grooves continue to the root surface, periodontal problems may result, although grooves were also present on the tooth surface, no caries or periodontal problems were found. Pit and fissure sealants were applied to both the fused teeth as a preventive measure [Figure 3].
Figure 3: Pit and fissure sealant application for <72–73> and <82–83>

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The management of a case of fusion depends on which teeth are included, the level of fusion, and the morphologic result. If the affected teeth are primary, they may be retained as they are. If the clinician intends extraction, it is important to first determine whether the corresponding teeth are present. Treatment of a fused tooth will depend on the clinical situation. If the fused tooth is free from caries, it may require no particular treatment. Universal preventive advice should be given to the parent and the child, and if caries already exists, a restoration should be performed to retain function and esthetics. If there is pulpal involvement, endodontic treatment should be conducted as it would for a multi-rooted tooth.

The most common problem related to double teeth is hypodontia of the permanent dentition. The anomalies of the permanent dentition are strongly associated with anomalies in the primary dentition.[9] Consequently, early diagnosis of this anomaly is important and should be followed by careful clinical and radiographic observations that will allow surgical intervention at an appropriate time. The present cases continue to be followed by our department with a multidisciplinary view [Figure 4].
Figure 4: Follow-up after 3 years

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  Conclusion Top


Dental fusion is asymptomatic, but the squeal will result in number of difficulties such as, tooth reduction in the permanent successors, increased susceptibility to subgingival bacterial plaque, aplasia or malformation of the permanent successors and impaction. The potential clinical problems associated with fusion require orthodontic, prosthetic, cosmetic, and periodontal intervention also. Thus, to establish a right treatment to this anomaly, the early proper examination and knowledge to recognize the anomalies associated between primary dentition and permanent dentition is a prerequisite.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Şekerci AE, Şişman Y, Ertaş ET, Gümüş H, Ertaş H. Clinical and radiographic evaluation and comparison of six cases of fusion involving the primary dentition. J Dent Child (Chic) 2012;79:34-9.  Back to cited text no. 1
    
2.
Kjaer 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.  Back to cited text no. 2
    
3.
Neville BW, Damm DD, Allen CM, Bouquot JE, editors. Abnormalities of the teeth. In: Oral and Maxillofacial Pathology. 2nd ed. New Delhi, India: Elsevier; 2005. p. 49-106.  Back to cited text no. 3
    
4.
Alpöz AR, Munanoǧlu D, Oncag O. Mandibular bilateral fusion in primary dentition: Case report. J Dent Child (Chic) 2003;70:74-6.  Back to cited text no. 4
    
5.
Chalakkal P, Thomas AM. Bilateral fusion of mandibular primary teeth. J Indian Soc Pedod Prev Dent 2009;27:108-10.  Back to cited text no. 5
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6.
Rajashekhara BS, Bhavna D, Manjunatha BS, Poonacha KS, Sunanda GS. Bilateral fusion of primary mandibular lateral incisors and canines: A report of a rare case. Rev Odontociênc 2010;25:427-9.  Back to cited text no. 6
    
7.
Cho SY. Primary double tooth: Report of a rare correlation with the permanent dentition. Prim Dent Care 2007;14:48-50.  Back to cited text no. 7
    
8.
White SC, Pharoah MJ. Dental anomalies. In: Penny R, editor. Oral Radiology: Principles and Interpretation. 5th ed. St. Louis, Mo.: Mosby Inc.; 2004. p. 337-8.  Back to cited text no. 8
    
9.
Shilpa G, Gokhale N, Mallineni SK, Nuvvula S. Prevalence of dental anomalies in deciduous dentition and its association with succedaneous dentition: A cross-sectional study of 4180 South Indian children. J Indian Soc Pedod Prev Dent 2017;35:56-62.  Back to cited text no. 9
[PUBMED]  [Full text]  
10.
Hagman FT. Anomalies of form and number, fused primary teeth, a correlation of the dentitions. ASDC J Dent Child 1988;55:359-61.  Back to cited text no. 10
    
11.
Veerakumar R, Arul PM, Prabhu MN. Caution! We are erupting as twins. J Clin Diagn Res 2011;5:1123-4.  Back to cited text no. 11
    
12.
Zengin AZ, Celenk P, Gunduz K, Canger M. Primary double teeth and their effect on permanent successors. Eur J Paediatr Dent 2014;15:309-12.  Back to cited text no. 12
    
13.
Reddy VR, Chowdhary N, Mukunda KS, Kiran NK, Kavyarani BS, Pradeep MC, et al. Retention of resin-based filled and unfilled pit and fissure sealants: A comparative clinical study. Contemp Clin Dent 2015;6:S18-23.  Back to cited text no. 13
    


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



 

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