Dental Hypotheses

: 2016  |  Volume : 7  |  Issue : 1  |  Page : 25--27

Ectopic eruption: Management of a partial mandibular lateral incisor transposition in a case report

Amirhossein Mirhashemi1, Fatemeh Gorjizadeh2, Omid Mortezai3,  
1 Department of Orthodontics, Dental Research Center, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
2 Department of Orthodontics, School of Dentistry, Tehran University of Medical Science, Tehran, Iran
3 Department of Orthodontics, School of Dentistry, Qazvin University of Medical Sciences, Qazvin, Iran

Correspondence Address:
Fatemeh Gorjizadeh
Department of Orthodontics, Tehran University of Medical Sciences, Tehran


Introduction: tooth transposition is a rare condition especially in the mandibular arch. Management of this condition is so hard, complicated and unknown for most of the clinicians. Case report: In this report we describe a case of orthodontic management of a partial mandibular left lateral incisor and canine transposition. We used a modified lingual arch appliance for initial correction of tooth transposition, more detailing was achieved by fix treatment. Discussion: Early detection of this anomaly is very important. Providing panoramic radiography to assess the developing dentition during the age of 6 to 8 years is an apropos forethought.

How to cite this article:
Mirhashemi A, Gorjizadeh F, Mortezai O. Ectopic eruption: Management of a partial mandibular lateral incisor transposition in a case report.Dent Hypotheses 2016;7:25-27

How to cite this URL:
Mirhashemi A, Gorjizadeh F, Mortezai O. Ectopic eruption: Management of a partial mandibular lateral incisor transposition in a case report. Dent Hypotheses [serial online] 2016 [cited 2020 Aug 3 ];7:25-27
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Tooth transposition is described as the positional interchange of two adjacent teeth. [1],[2],[3] It has a prevalence of 0.33%. [4] The most commonly transposed tooth is the maxillary canine. [1] Additionally, it is reported that the lateral incisor is most often the ectopically displaced tooth in the mandibular arch. [1],[5]

The objective of this paper is to report a case of a male child patient who presented with unilateral ectopic eruption of the mandibular permanent lateral incisor and to discuss both implications regarding such an anomaly and treatment outcomes.

 Case Report

A male patient of 10 years and 6 months was brought to the orthodontic clinic of Tehran University of Medical Sciences (TUMS), Tehran, Iran; complained that the child's mandibular tooth "appeared to be erupted badly."

On intraoral examination, the patient was in a mixed dentition stage. Mandibular permanent left lateral incisor was found to be ectopically erupted, with the crown transposing near the permanent canine crown bulge and a severe mesiolingual rotation. Bolton analysis revealed undersized upper lateral incisors [Figure 1].{Figure 1}

On radiographic examination, the partial transposition of the permanent mandibular left lateral incisor was diagnosed; the apex of the ectopic tooth was right above the crown of permanent canine [Figure 2].{Figure 2}

Orthodontic treatment began with a lingual arch appliance having a small buccolingual bar-like extension right distal of the left lower central incisor in order to move the ectopic tooth mesially as well as derotating the tooth during this movement. Two bondable lingual buttons were bonded to mesiolingual and distobuccal surfaces of the tooth to attach the elastic threads from the lingual arch to them while making the control of the tooth angulation much easier. During the incipient movement when roots were very close, periapical radiographs were obtained to check the position and possible root resorption.

After correction of transposition, a removable appliance with a finger spring was placed at the distal side of ectopic tooth that was used as a retainer until fixed orthodontic began.

After 4 months, an edgewise appliance was placed on the erupted permanent teeth. The abnormally erupted lateral incisor was moved accurately into a position beside the right central incisor. As the remaining teeth erupted, all maxillary and mandibular teeth were bonded with the same appliance. When the final result was obtained, there were spaces distal to the maxillary incisors, which was due to tooth size discrepancy; therefore, the patient was referred to the cosmetic department for tooth composite buildup. The appliances were removed, and Hawley retainers were placed in both the mandible and the maxilla to maintain the orthodontic correction [Figure 3].{Figure 3}


Tooth transpositions are classified as complete or incomplete. In a complete transposition case, crowns and roots of the involved teeth are in the transposed position, whereas in an incomplete transposition case, the crowns may interchange, although, the root apices are placed in their normal positions. [1] Our case was an incomplete tooth transposition.

Early detection and immediate removal of the retained deciduous lateral incisor and canine will prevent the developing transposition. [6] Different dental anomalies have been reported in conjunction with transposition. [1],[7] At the present case, there was a 3.1 mm Bolton tooth size discrepancy due to small maxillary lateral incisors that could be related. However, a meta-analysis study has suggested that tooth transposition is an isolated phenomenon and it can be accompanied by a variety of dental anomalies, but with no distinct associations. [8]

The clinical findings observed in the early stages of mandibular lateral incisor and canine transpositions in mandible are the distal tipping, coronal displacement, and severe mesiolingual rotation of the mandibular lateral incisor. In the later stages, mandibular canine erupts in the position of the lateral incisor. [2] In this case, the permanent lateral incisor had migrated distally along the lingual side of permanent canine and led to early loss of deciduous canine and probably deciduous first molar, and had erupted in the canine space with severe rotation. This patient had the typical characteristics of mandibular lateral incisor and canine transposition described by Peck. [2] At the present case, lateral incisor had migrated completely to the canine area and its root had become upright to a superimposed relationship with unerupted canine crown. Because the canine was unerupted and had a low and labial positon in the alveolar bone, the treatment plan was the guidance of the ectopic lateral incisor to its normal position which could preserve the integrity of the dental arch. The mandibular teeth were moved to their correct positions, the symmetry and harmony of the dental arch were maintained, and canine guidance was created for lateral mandibular movements in a functional Class I occlusion.

The prevalence of tooth transposition in the mandible is low, and case reports describing the correction of this transposition are few. Shapira and Kuftinec described the correction of mandibular lateral and canine transposition using a modified lingual arch. [5] Taner and Uzamýs, in addition, used a modified lingual arch to treat one patient, and a utility arch and elastics to treat another.[9] Yaillen reported using techniques similar to ours to correct a transposition. [10] The patients in all these reports had been diagnosed before eruption of the permanent canine.

In patients with tooth transposition, the decision to choose the type and design of treatment depends on the severity of malocclusion and the time of diagnosis. Early detection can make treatment planning much easier and prevent tooth extraction or a compromised occlusion and aesthetic. Providing panoramic radiography to assess the developing dentition at the age of 6-8 years for early detection of this anomaly as well as many other dental developmental anomalies is an apropos forethought.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Tehran University of Medical Sciences has supported this research.

Conflicts of interest

No confilict of interest is present.


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