speciai Report

Transmigration of mandibnlar canines: A review of the literatnre andreport of two casesM.R.Joshi*/S.B.Shetye*"^

Transmigration of mandibular canines across Ihe midline is rare. Two 14-year-old femalepatients from Souih India were found to exhibit this phenomenon. In one patient, the mandib-ular right canine had crossed the midline and migrated to the left, up to the mesial root apex ofthe permanent first molar, near the lower border ofthe mandible. In the other patient, the per-manent mandibular left canine had crossed the midline and migrated up to the root of lhemandibular right canine. Both of these patients are being observed regularly for furthermigration. The literature on this rare condition is reviewed and its etiologicpossibilities andtreatment modalities are discussed. (Quintessence Int 1994;25:291-294. )

Introduction

An unerupted tooth occasionally migrates to a locationsome distance away from the site in whieh it develops.Such teeth almost always are displaced within the sameside of the arch. The movement of an unerupted toothacross the dental midline is unusual and, therefore,worthy of investigation. Tarsitano et al' described thisanomaly as transmigration, or movetnent of an un-erupted tooth across the midline without the influenceof any pathologic entity.

Because this phenomenon is so rare, it was thoughtthat the two cases of canine transmigration across themandibular midline observed at the KLES Dental Col-lege and Hospital in South India, merited reporting.

' Professor, Department of Orthodontics, KLES Dental Collegeand Hospital. Belgaum, Karnataka, India; Private Practice, 4,Vikas Society, Near Drive-In-Cinetna. Memnagar, Ahmedabad3S00S2, India.Professor. Department of Orthodontics, KLES Dental Collegeand Hospital; Private Practice, Sulochana Niwas, Alto Betim,Bardez, Goa, India.

Case reports

Case!

A normal and heahhy girl, aged 14 years, had Angle'sClass I malocelusion. crowded mandibular incisors, anda lingually placed left lateral incisor. Tbe mandibulardental midhne was shifted to the left, and the primaryright canine was overretained. Radiographs revealedan impacted and migrated mandibular right canine.The tooth had migrated across the midline and was sit-uated below tbe roots of permanent left first molar,near the lower border of the mandible (Fig 1).

Case 2

A normal and healthy girl, aged 14 years, had Angle'sClass I malocelusion with slightly crowded and pro-truding mandibular incisors. The mandibular dentalmidline was shifted to the left and a 6.0-mm space waspresent between the mandibular left lateral incisor andfirst premolar. Radiographs revealed that the impactedpermanent mandibular left canine had migrated acrossthe midline, toward the right side of the mandible, andwas situated near the root of the mandibular right ca-nine. The migrating canine, although it had crossed themidline. was still in the symphyseal area (Fig 2).

QuintessencelnteriialioriaLJigluinaÄ^umber 4/1994 291

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Figs 1 a (above) and 1 b (right) Radiograpins of the patientin case 1, showing the horizontal position of the transmi-grated mandibular right canine below the permanent leftfirst moiar roots. The ouerretained primary right canine canalso be seen.

Figs 2a (above) and 2b (right) Radiographs ot the patientin case 2. showing the horizontal position of the transmi-grated mandibular left canine and its relationship to the api-ces of the mandibuiar incisors.

Review ofthe literature

A compilation of descriptions of various transmigratedmandibular canines reported by different authors isgiven in Tabie 1. Caldwell" appears to have beeti thefirst to describe this kind of anomaly. Most of the subse-quent reports have described single cases. However,

Tarsitano et al' described three cases. Howard'^ inves-tigated eight cases, and Javid"" presented areport of 13cases of transmigration. Joshi et al''' reported, for thefirst time, one case of bilateral transmigration of man-dibular eanines crossing the midline. Javid"' observedthree cases of bilateral transmigration among his col-lection of 13 cases. Javid"' considered tooth movemetit

292 Quintessence Intemational Voiume 25, Number 4/1994

Special Report

Table 1 Cliriical features of transmigrated mandibular canines reported in the English literature

Author Canine* Position of the crown

of the transmigrated canineNo, of Eruptioncases status'

Sex ofpatient"

Caldwell-

Bruszt'

Stafne-*

Ando et aP

Kaufman and Buchner*'

Fiedler and Ailing'

Pratt*

Thoma''

Tarsitano et al'

Black and Zallen'"

Miranti and Levbarg"

Howard'^

Barnett"

Joshietal'*'

Shapiraetal'''

Javid'"

Present study

R

L

R

NM

R

R

R

R

NM

L

L

R

L

R

L

B

L

R

R

NMB

RL

Below distal mot of first molar

Up to canine

Up to canine

Below canine

Below apex of first premolar

Up to canine

Below apex of first premolar

Near mesial surface of left canine

Mesial of first premolar

Below mental foramen

Below right eanine

Below apex of anterior teeth

Two below central incisor;thTee below lateral incisor

One below canine: two below first premolar

Up to canine

Up to lateral incisors

Up to lingual surface of lateral incisor

Up to canine root

Up to canine root {odontoma present)

Up to first molar

Below roots of permanent left first molarUp to root of right eanine

1

1

1

1

1

1

1

1

1

3

1

1

5

3

1

1

1

1

1

103

11

I

E^

E*

I

I

E*

I

E*

I

I

I

I

I

I

E*

I

E«

I

I

II

I

I

F

F

F

NM

M

F

F

M

NM

NM

M

F

6F/2M

F

M

F

M

F

6F/4M2F/1M

F

F

R - right; L = left; NM - DOI mentioned; B = bilateral,I = impacted; E = erupted.Labially erupted,Lingually enipted,F = female; M - male; NM = not mentioned.

to be transmigration only if an impacted canine hadcrossed over the midline by more than half its length.

Unilateral eases (38) have been reported more oftenthan bilateral ones (4), Females appear to have a high-er incidence of canine transmigration than do males (25F:12 M). However, occurrence appears to be almosteqtially divided between the right side and the left side

(13 R:l l L), Almost all the transmigrated canines, 40of 46, were impacted. Of the six canines that haderupted, five had erupted labially and only one wasfound to have erupted lingually. The two cases reportedin the present paper are included in the above-men-tioned observations. It needs to be noted that Thoma,"*Stafne,'̂ and Javid'" did not mention whether the affect-

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Special Report

ed tooth was from the right or left side, Thoma,''Stafne,'' and Tarsi-tano et al' did not mention the sex ofthe patients in their reports of such cases.

As in the cases reported by Howard,'" in the twocasesreportedin the present paper it has been assumedthat the eanines did not develop in the region in whichthey were found, but had migrated Ihere from a posi-tion in or near their eoneet developmental site. Evi-dence for this was inferential and was based on Ihe con-cept of migration confirmed earlier, with neurologicevidence, by Caldwell- and Bruszt-* and later proved ra-diologieally by Ando et al,̂

Theaxialinclinationof the canines to the midsagittalplane in cases 1 and 2 appeared to be 80 and 90 degrees,respectively. It has been suggested that all impacted ea-nines inclined more than 50 degrees are likely to mi-grate and cross the midline,'-

Shift of the dental midline to the affeeted side is acommon feature of this condition,'- In both the casespresented in the present paper, the midline was shiftedto the left side; however, a right canine and a left caninewere involved in the migration process.

In the patient in whom the canine had migrated to aposition near the mesial roots of the permanent firstmolar, the mandibular incisors showed incisor-man-dibular plane angle of 91,5 degrees (see Fig 1), In theother patient, in whom the canine had just crossed themidline but had not completely passed the incisor area,the incisor-mandibular plane angle measured 115,0 de-grees (see Fig 2), This observation meagerly supportsthe slender evidence in Howard's paper'- suggestingthat the canine is instrumental in producing the man-dibular incisor proclinalion.

Although it is nol possible lo identify a definite etio-logic or predisposing factor responsible for this kind oftransmigration process, it has been suggested that, forsome reason, the canine becomes deviated in a hori-zontal position, and an abnormally strong eruptionforce directed toward the crown" drives the caninethrough the dense symphysis. This force pushes thetooth as far as the roots ofthe permanent first molar oreven further on the opposite side. Moreover, the coni-cal shape of the crown and the root of Ihe mandibularcanine facilitates its transmigration process within themandible,"'

Surgical extraction appears to be the most favorabletreatmenl for migrated canines, rather than making aheroic effort to bring the tooth back to its originalplaee. This is especially true when the mandibular archis crowded and requires therapeutic extractions to cor-rect the incisor erowding. However, if the other teeth

are io a normal position and spaee for the transmi-grated canine is sufficient, a transplantation processmay be undertaken,'-

At present both the patients in this report are beingregularly observed clinically and radiographically.Over the last year, the canines have not moved any fur-ther. Both the canines at present are asymptomatic.The patient in whom the eanine has migrated nearly tothe first molar is receiving orthodontic treatment formaloeclusion in her maxillary arch. No orthodontictreatment is contemplated for her mandibular arch.

AcknowledgmentsSini;ere ihaiiks are due lo Dr Kalyani. Assislanc Professor ot Orlho-donlics, and la Dri Vijay. Girish, and Keluskar, students in the De-partment of Orthodontics, for Iheir help in maintaining the records;ind the photographic work for the two cases presented in thispaper.

References1, Tarsilano JJ, Woolen JW, BurdiU JT, Transmigration of non-

ernpled mandibular canines; Report of cases. J Am Dent AssocI97l;fí2:l.'i95-I397,

2, Caldwell JB, Neurological anomaly associated with extrememalposition of a mandibular canine. Oral Surg Oral Med Oral

Bruszt P Neurological anomaly associated with extreme mal-position of a mandibular canine. Oral SurgOral Med Oral Path-ol 1958;tl:89-90.Sfafne EC, Malposcd mandibular canine. Oral Surg Oral MedOral Pathol 1963;l6:t330,Ando S, Aizawa K, Nakashima T, Sanka Y, Shimbo K, Kiyo-kawa K, Transmigration process of the impacted mandibularcuspid. J Nihon Univ SthDent 1%4;6:66-71,Kaufman AY, Buchnci A. Transmigration of mandibular ca-nine. Oral Surg Oral Med Oral Pathol 19ö7;23;648-650,Fiedler LD, Ailing CC, Malpositioned mandibular right canine;Report of ease, J Oral Surg t968;26:405^06,Pratt RJ, Migration of eanine aeross the mandibular midline, BrDentJ I%9;126:463^64,

Tlioma KH, Oral Surgery, ed 5. Si Louis; Mosby, 1969;54-55,Black SL, Zallen RD. An unusual case of tooth migration. OralSurg t973:36;607-608,

Miranli R, Levbarg M, Estraction of horizontally transmi-grated impacted mandibular canine; Report of case, J Am DentAssoc 1974;88;607-610,Howard RD The anomalous mandibular canine, Br J Orthodt976;3;t 17-119,

Barnett DP, An unusual transposition, BrJ Orthod 1977;4;149,Joshi MR, Daruwala NR, Ahuja H C Bilateral transmigrationof mandibular canines, Br J Orthod 1982;9;57-58,Shapira Y. Mischler W, Kuflincc MM. The displaced mandib-ular canine, J Dent Child 1982;49;362-364,Javid B, Transmigration of impacted mandibular euspids, Inl JOral Surg 1985;14;547-549.

Sutton PRN. Migration and eruptiori of non-erupted teeth; Asuggestedmeehanism, Aust Dent J t%9;14;269-270, •

294 Quintessence International Volume 25, Number 4/1994