Radiographic evidence is given that docum ents the ectopic movement of an unerupted canine from its normal developmental site to a position apical to the m andibular anterior teeth in a young boy. The clinician would be well advised, particularly in dealing with arch length deficiency problems, to defer the removal of permanent teeth until he is well assured of a normal eruption pattern of the teeth to be preserved.
Ectopic movement of an unerupted mandibular canine
Saul N. G reenberg, DDS Alvin I. Orlian, DDS, F lu sh in g , NY
A lthough d en tal lite ra tu re has re c o rd e d the not uncom m o n clinical e x p e rie n c e o f identifying u n eru p ted an d eru p te d te e th fa r fro m th eir norm al sites o f d e v e lo p m e n t, th e a c tu a l rad io g rap h ic evid en ce o f th is m o v em en t h a s rarely b een d o c um en ted . A rev iew o f th e lite ra tu re has u n c o v ered only o n e a rtic le 1 th a t gives radiographic evid en ce d uring an 11-year p e rio d o f a m andib ular seco n d p re m o la r’s tra v e lin g a d ista n c e of ab o u t 6 cm , from th e region o f th e m ental fo ra m en to a p o sitio n high in th e c o ro n o id p ro cess. T h e re also h av e b e e n sev eral re p o rts o f m andib u lar can in es th a t h av e p re su m a b ly cro sse d the m idline and re lo c a te d on th e o p p o site side of the m andib le, u su ally as h o riz o n ta l im p actio n s or, m ore ra re ly , th ey h av e e ru p te d a d ja c e n t to the o p p o site c a n in e .2-6 T h e su p p o sitio n o f m ig ratio n ra th e r th a n in situ dev elo p m en t h as b e e n d e riv e d from sev eral fa cto rs. In n e rv a tio n o f th e m ig rated to o th co m es fro m th e o p p o site side; th a t is, a c an in e lo cated in th e b o d y o f th e right side o f th e m andible re ceives its in n erv atio n an d p re su m a b ly v a sc u la r supply from th e left side. T h e tw o te e th are m ir
ro r im ages o f each o th er. A n d , alth o u g h th e re are tw o can in es on one side, the o p p o site side has n o n e o r has an o v e rre ta in ed d ec id u o u s c a nine. It is n o t th e in ten t o f th is article to re v iew the vario u s th eo ries on e ru p tio n an d m o v e m e n t o f th e tee th befo re eru p tio n . T h e a c tu a l m e c h a n ism o r m echanism s resp o n sib le fo r this p h e n o m en o n a re still n o t clearly u n d e rs to o d .1,7 T h e re p o rt is o f significance in th a t radiog rap h ic ev id e n ce is available th a t a c tu ally d o c u m e n ts this ecto p ic m ov em en t.
R e p o rt o f case A n 8-year-old w hite boy w as re fe rred to one of u s (S .N .G .) fo r co n su lta tio n and tre a tm e n t fo r th e c o rre c tio n o f a C lass II D iv isio n 1 (A ngle) m alocclusion. T h e p a tien t w as in good health an d no significant m edical h isto ry w as re c o rd e d . O rth o d o n tic diagnostic re c o rd s w ere ta k e n , in cluding full-m outh and lateral ja w rad io g rap h s, c e p h alo m etric rad io g rap h s, p h o to g ra p h s, and JADA, Vol. 93, July 1976 ■ 125
Fig 1 ■ Pretreatm ent cephalom etric X ray o f 8-year-old boy. Note
Fig 2 ■ Pretreatm ent periapical radiograph of patient showing
position of unerupted left permanent canine.
position of m andibular le ft canine at tim e of initial exam ination.
stu d y m odels. A nalysis o f the re c o rd s in d icated th e m alocclu sio n to be a m axillary p ro tru sio n w ith a 13-mm a n te rio r o v erjet; th e possibility th a t an arch-length deficien cy w as developing w as reco g n ized (Fig 1). A t the tim e o f th e initial ex am in atio n , th e m axillary and m an d ib u lar four p e rm a n e n t a n te rio r te e th an d m axillary an d m an d ib u lar first p erm an en t m olars h ad e ru p te d . T h e m axillary decid u o u s ca n in e s, first and second d e c id u o u s m o lars, and m an d ib u lar first an d sec o n d d ecid u o u s m olars w ere p re se n t. T h e m an d ib u lar d ecid u o u s canines had a p p a re n tly been p rev io u sly exfoliated to a c c o m m o d a te th e e ru p t ing p e rm a n e n t m andibular lateral inciso rs. A n al ysis o f th e arch length in d icated a p o ten tial a rc h length deficien cy of 3 m m . In tra o ra l and lateral ja w rad io g rap h s show ed th e rem aining u n e ru p t ed p e rm a n e n t te e th , including th e m andibular left can in e to be developing norm ally an d a p p a re n tly in norm al position fo r th e e ru p tio n cycle (F ig 2). S ince th e arch-length deficien cy w as m inim al, th e tre a tm e n t plan objectiv es in v o lv ed th e re d u c tio n o f th e a n te rio r d en to a lv e o la r p ro tru sio n by u se o f high-pull h ead g ear an d m an d ib u lar appli an c e th e ra p y to m aintain in teg rity o f th e m an d ib u lar arch so th at th e rem aining u n eru p ted p e rm a n e n t te eth could b e a c c o m m o d ated in the n orm al arch fo rm w ith o u t re so rtin g to th e re m oval o f an y teeth . T re a tm e n t p ro g ressed as an tic ip a te d and in 18 m o n th s norm al arch form and alignm ent had b een estab lish ed and m aintained as th e decidu126 ■ JADA, Vol. 93, July 1976
Fig 3 ■ Occlusal film show ing movement of m andibular left canine in 30 m onths. Compare with Figures 1 and 2.
ous te eth exfoliated and w ere rep laced by th e ir p e rm a n en t su cc esso rs. T h e eruption p a tte rn , al though so m ew h at a d v a n c ed , follow ed the n o r mal seq u en ce including b ilateral, sequential sym m etry. T h e re fo re , w hen th e m andibular left canine failed to e ru p t after th e ap p e aran ce o f its c o n trala teral m ate, intrao ral radiographs w ere o rd ered . T h e periapical radiograph failed to show the p rese n ce o f th e canine and the possibility o f a sp o n ta n eo u s re so rp tio n w as d iscounted. A n occlusal radiograph show ed th a t in a period o f a b o u t 30 m onths th e m andibular left canine had m igrated from its norm al developm ental site to a h o rizontal p o sitio n in ferio r to the ap ex es of the fo u r m an d ib u lar incisors (F ig 3). T h e position o f th e canine w as such th at the decision w as m ade to e x tract th e tooth and to ad v an ce orth o d o n tically th e left p o ste rio r seg m ent to elim inate the can in e space. T h e patient
Fig 4 ■ Panoram ic radiograph of migrated m andibular left canine before its surgical removal. Note ra dioluce nt areas encircling crown.
w as refe rred to an oral su rg eo n (A .I.O .) fo r the surgical p ro ced u re.
S u rg ic a l P ro c e d u re O n O ct 31, 1974, th e p a tie n t, n o w 10 y ears o f age, w as ex am ined and referred fo r th e rem oval o f a m igrated , im pacted m an d ib u lar left canine. C linical exam in atio n in d icated a p ainless h ard sw elling o f th e a n te rio r a sp e c t o f th e m andible. T h e ov erlying m ucosa w as norm al. R adio g rap h ic exam in atio n sh o w ed an a p p a r ently m igrated m andibular left can in e h o rizo n tally im p acted below th e fo u r m an d ib u lar a n te r ior teeth . A d isc re te rad io lu cen t a re a encircled the can in e crow n (F ig 4). T h e eru p ted a n te rio r te e th w ere vital an d free o f an y u n to w ard sym p tom s. A n e sth e sia w as given by b ilateral m ental in je c tio n s o f lidocaine h y d ro ch lo rid e (1:100,000 epinep h rin e). T h is w as su p p le m e n te d w ith m in im al local infiltration. V ertical incisions w ere m ade m esial to th e first prem o lars an d w ere c o n n e c te d by incising the co ro n al gingiva o f th e in terv en in g teeth . T h e m u co p erio steu m w as reflected inferiorly to b e n eath th e buccal ex pan sio n . T h e o v erlying b one w as rem o v ed to ex p o se th e im p acted coronal a sp e c t o f th e to o th . T o p re se rv e th e o sseo u s stru c tu re , th e cro w n w as se c tio n e d an d rem oved and su b seq u en tly the ro o t w as e x tra c te d . T h e are a w as d eb rid ed and the tissu e w as co ated with in terru p te d no. 0-3 silk su tu re s. P o sto p e ra tiv e ly , th e re w as m o d erate ed em a and m inim al pain. T h e su tu re s w ere rem oved five days p o sto p erativ ely an d healing w as u n com plicated.
D iscu ssio n A lthough th e actual m echanism o f eru p tio n or m igration o f an u n eru p te d to oth is n o t co m p lete ly u n d e rsto o d , it has been generally a c ce p ted th at an u n e ru p te d to oth will “ follow th e p ath of lea st re s is ta n c e .” 8 It is not unusual fo r th e clin ician to see canines in lab io v ersio n o r palato v ersion, and p rem o lars in linguoversion in th o se individuals w ith noticeab le crow ding, in d icat ing an a lv e o lar arch-length, to oth-size d iscrep an cy . In treating the m ixed den titio n , o rth o d o n tists h av e th re e goals: to red irect v e cto rs of g row th so th a t a norm al m u sculoskeketal en v ir on m en t o f facial c o m p o n en ts is estab lish ed and m aintained during th e grow th p eriod; to e n c o u r age arch-length dev elo p m en t to ac co m m o d ate th e full co m p lem en t o f p e rm a n en t tee th ; a n d , to d evelop a serial e x tra ctio n program involving th e early ex tra ctio n o f first p rem o lars w hen it has been d eterm in ed th a t the d iscrep an cy betw een to o th size and alv eo lar arch length is sufficient to p reclu d e norm al positioning o f th e te e th in the p e rm a n e n t dentition. E arly tre a tm e n t in th is in stan ce w as u n d e r tak en to accom plish th e first tw o objectives: in o th e r w o rd s, to develop norm al arch form and fu n ctio n , and to guide th e developing arch length so th a t all th e p erm an en t te e th , ex cep t th ird m o lars, w ould be acco m m o d ated in th e m ature arch . A n alysis o f th e case indicated th a t th e m alocclusion w as prim arily dental in origin and th at prognosis w as fav o rab le fo r elim inating th e arch-length deficiency. T h is la tte r decision w as m ost fo rtu n a te since a m ore com plex problem w ould have ensued if the first p rem o lars had been e x tra c te d as m ight have been the case if the G reenberg— O rlian: ECTOPIC MOVEMENT OF CANINE ■ 127
arch-length discrepancy had been more pro nounced. A migrating tooth will move in the direction in which the crown is pointed9 and the crown will maintain the lead during migration. Therefore, in the instance of mandibular canines, their path way of migration is mesial and, as in this case, it is possible for the tooth to unaccountably rotate from an apparently normal development posi tion to assume a horizontal intraosseous migra tion apical to the anterior teeth.
Summary A case history has been given with the radiographic evidence of the migration, during devel opment of an unerupted mandibular canine from its normal position. In a 30-month period the ca nine assumed a horizontal position and moved to a site that was apical to the mandibular inci sors, still in the confines of the cortical plates. Because erratic movements of unerupted teeth cannot be anticipated, it would seem wise to de fer the elective removal of permanent teeth dur
128 ■ JADA, Vol. 93, July 1976
ing the mixed dentition stage until the clinician is assured of a normal eruption pattern of the succedaneous teeth.
Dr. Greenberg is an orthodontist at 143-33 Sanford Ave, Flushing, NY 11355. Dr. Orlian is an oral surgeon and director of dentistry, Flushing Hospital. Address requests for reprints to Dr. Greenberg. 1. Stafne, E.C. Oral roentgenographic diagnosis, ed 2. Phil adelphia, W. D. Saunders Co., 1963, p 53. 2. Black, S.L., and Zallen, R.D. An unusual case of t’ooth migra tion. Oral Surg 36:607 Oct 1973. 3. Fiedler, L.D., and Ailing, C.C. Malpositioned mandibular right canine: report of case. J Oral Surg 26:405 June 1968. 4. Pratt, R.J. Migration of canine across the mandibular mid line. Br Dent J 126:463 May 20, 1969. 5. Stafne, E.C. Malpositioned mandibular canine. Oral Surg 16:1330, 1963. 6. Tarsitano, J.J.; Wooten, J.W.: Burditt, J.T. Transmigration of nonerupted mandibular canines: report of cases. JADA 82: 1395 June 1971. 7. Moss, M.L.; Greenberg, S.N.; and Noback, C.R. Develop mental migration of mandibular buccal dentition in man. Angle Orthod 29:169 July 1959. 8. Hutchinson, A.C. Dental and oral X-ray diagnosis. Edin burgh, E & S Livingstone, 1954, pp 46, 52, 113. 9. Sutton, P.R. Migrating nonerupted mandibular premolars: a case of migration into the coronoid process. Oral Surg 25:87 Jan 1968.
Ectopic movement of an unerupted mandibular canine
Saul N. G reenberg, DDS Alvin I. Orlian, DDS, F lu sh in g , NY
A lthough d en tal lite ra tu re has re c o rd e d the not uncom m o n clinical e x p e rie n c e o f identifying u n eru p ted an d eru p te d te e th fa r fro m th eir norm al sites o f d e v e lo p m e n t, th e a c tu a l rad io g rap h ic evid en ce o f th is m o v em en t h a s rarely b een d o c um en ted . A rev iew o f th e lite ra tu re has u n c o v ered only o n e a rtic le 1 th a t gives radiographic evid en ce d uring an 11-year p e rio d o f a m andib ular seco n d p re m o la r’s tra v e lin g a d ista n c e of ab o u t 6 cm , from th e region o f th e m ental fo ra m en to a p o sitio n high in th e c o ro n o id p ro cess. T h e re also h av e b e e n sev eral re p o rts o f m andib u lar can in es th a t h av e p re su m a b ly cro sse d the m idline and re lo c a te d on th e o p p o site side of the m andib le, u su ally as h o riz o n ta l im p actio n s or, m ore ra re ly , th ey h av e e ru p te d a d ja c e n t to the o p p o site c a n in e .2-6 T h e su p p o sitio n o f m ig ratio n ra th e r th a n in situ dev elo p m en t h as b e e n d e riv e d from sev eral fa cto rs. In n e rv a tio n o f th e m ig rated to o th co m es fro m th e o p p o site side; th a t is, a c an in e lo cated in th e b o d y o f th e right side o f th e m andible re ceives its in n erv atio n an d p re su m a b ly v a sc u la r supply from th e left side. T h e tw o te e th are m ir
ro r im ages o f each o th er. A n d , alth o u g h th e re are tw o can in es on one side, the o p p o site side has n o n e o r has an o v e rre ta in ed d ec id u o u s c a nine. It is n o t th e in ten t o f th is article to re v iew the vario u s th eo ries on e ru p tio n an d m o v e m e n t o f th e tee th befo re eru p tio n . T h e a c tu a l m e c h a n ism o r m echanism s resp o n sib le fo r this p h e n o m en o n a re still n o t clearly u n d e rs to o d .1,7 T h e re p o rt is o f significance in th a t radiog rap h ic ev id e n ce is available th a t a c tu ally d o c u m e n ts this ecto p ic m ov em en t.
R e p o rt o f case A n 8-year-old w hite boy w as re fe rred to one of u s (S .N .G .) fo r co n su lta tio n and tre a tm e n t fo r th e c o rre c tio n o f a C lass II D iv isio n 1 (A ngle) m alocclusion. T h e p a tien t w as in good health an d no significant m edical h isto ry w as re c o rd e d . O rth o d o n tic diagnostic re c o rd s w ere ta k e n , in cluding full-m outh and lateral ja w rad io g rap h s, c e p h alo m etric rad io g rap h s, p h o to g ra p h s, and JADA, Vol. 93, July 1976 ■ 125
Fig 1 ■ Pretreatm ent cephalom etric X ray o f 8-year-old boy. Note
Fig 2 ■ Pretreatm ent periapical radiograph of patient showing
position of unerupted left permanent canine.
position of m andibular le ft canine at tim e of initial exam ination.
stu d y m odels. A nalysis o f the re c o rd s in d icated th e m alocclu sio n to be a m axillary p ro tru sio n w ith a 13-mm a n te rio r o v erjet; th e possibility th a t an arch-length deficien cy w as developing w as reco g n ized (Fig 1). A t the tim e o f th e initial ex am in atio n , th e m axillary and m an d ib u lar four p e rm a n e n t a n te rio r te e th an d m axillary an d m an d ib u lar first p erm an en t m olars h ad e ru p te d . T h e m axillary decid u o u s ca n in e s, first and second d e c id u o u s m o lars, and m an d ib u lar first an d sec o n d d ecid u o u s m olars w ere p re se n t. T h e m an d ib u lar d ecid u o u s canines had a p p a re n tly been p rev io u sly exfoliated to a c c o m m o d a te th e e ru p t ing p e rm a n e n t m andibular lateral inciso rs. A n al ysis o f th e arch length in d icated a p o ten tial a rc h length deficien cy of 3 m m . In tra o ra l and lateral ja w rad io g rap h s show ed th e rem aining u n e ru p t ed p e rm a n e n t te e th , including th e m andibular left can in e to be developing norm ally an d a p p a re n tly in norm al position fo r th e e ru p tio n cycle (F ig 2). S ince th e arch-length deficien cy w as m inim al, th e tre a tm e n t plan objectiv es in v o lv ed th e re d u c tio n o f th e a n te rio r d en to a lv e o la r p ro tru sio n by u se o f high-pull h ead g ear an d m an d ib u lar appli an c e th e ra p y to m aintain in teg rity o f th e m an d ib u lar arch so th at th e rem aining u n eru p ted p e rm a n e n t te eth could b e a c c o m m o d ated in the n orm al arch fo rm w ith o u t re so rtin g to th e re m oval o f an y teeth . T re a tm e n t p ro g ressed as an tic ip a te d and in 18 m o n th s norm al arch form and alignm ent had b een estab lish ed and m aintained as th e decidu126 ■ JADA, Vol. 93, July 1976
Fig 3 ■ Occlusal film show ing movement of m andibular left canine in 30 m onths. Compare with Figures 1 and 2.
ous te eth exfoliated and w ere rep laced by th e ir p e rm a n en t su cc esso rs. T h e eruption p a tte rn , al though so m ew h at a d v a n c ed , follow ed the n o r mal seq u en ce including b ilateral, sequential sym m etry. T h e re fo re , w hen th e m andibular left canine failed to e ru p t after th e ap p e aran ce o f its c o n trala teral m ate, intrao ral radiographs w ere o rd ered . T h e periapical radiograph failed to show the p rese n ce o f th e canine and the possibility o f a sp o n ta n eo u s re so rp tio n w as d iscounted. A n occlusal radiograph show ed th a t in a period o f a b o u t 30 m onths th e m andibular left canine had m igrated from its norm al developm ental site to a h o rizontal p o sitio n in ferio r to the ap ex es of the fo u r m an d ib u lar incisors (F ig 3). T h e position o f th e canine w as such th at the decision w as m ade to e x tract th e tooth and to ad v an ce orth o d o n tically th e left p o ste rio r seg m ent to elim inate the can in e space. T h e patient
Fig 4 ■ Panoram ic radiograph of migrated m andibular left canine before its surgical removal. Note ra dioluce nt areas encircling crown.
w as refe rred to an oral su rg eo n (A .I.O .) fo r the surgical p ro ced u re.
S u rg ic a l P ro c e d u re O n O ct 31, 1974, th e p a tie n t, n o w 10 y ears o f age, w as ex am ined and referred fo r th e rem oval o f a m igrated , im pacted m an d ib u lar left canine. C linical exam in atio n in d icated a p ainless h ard sw elling o f th e a n te rio r a sp e c t o f th e m andible. T h e ov erlying m ucosa w as norm al. R adio g rap h ic exam in atio n sh o w ed an a p p a r ently m igrated m andibular left can in e h o rizo n tally im p acted below th e fo u r m an d ib u lar a n te r ior teeth . A d isc re te rad io lu cen t a re a encircled the can in e crow n (F ig 4). T h e eru p ted a n te rio r te e th w ere vital an d free o f an y u n to w ard sym p tom s. A n e sth e sia w as given by b ilateral m ental in je c tio n s o f lidocaine h y d ro ch lo rid e (1:100,000 epinep h rin e). T h is w as su p p le m e n te d w ith m in im al local infiltration. V ertical incisions w ere m ade m esial to th e first prem o lars an d w ere c o n n e c te d by incising the co ro n al gingiva o f th e in terv en in g teeth . T h e m u co p erio steu m w as reflected inferiorly to b e n eath th e buccal ex pan sio n . T h e o v erlying b one w as rem o v ed to ex p o se th e im p acted coronal a sp e c t o f th e to o th . T o p re se rv e th e o sseo u s stru c tu re , th e cro w n w as se c tio n e d an d rem oved and su b seq u en tly the ro o t w as e x tra c te d . T h e are a w as d eb rid ed and the tissu e w as co ated with in terru p te d no. 0-3 silk su tu re s. P o sto p e ra tiv e ly , th e re w as m o d erate ed em a and m inim al pain. T h e su tu re s w ere rem oved five days p o sto p erativ ely an d healing w as u n com plicated.
D iscu ssio n A lthough th e actual m echanism o f eru p tio n or m igration o f an u n eru p te d to oth is n o t co m p lete ly u n d e rsto o d , it has been generally a c ce p ted th at an u n e ru p te d to oth will “ follow th e p ath of lea st re s is ta n c e .” 8 It is not unusual fo r th e clin ician to see canines in lab io v ersio n o r palato v ersion, and p rem o lars in linguoversion in th o se individuals w ith noticeab le crow ding, in d icat ing an a lv e o lar arch-length, to oth-size d iscrep an cy . In treating the m ixed den titio n , o rth o d o n tists h av e th re e goals: to red irect v e cto rs of g row th so th a t a norm al m u sculoskeketal en v ir on m en t o f facial c o m p o n en ts is estab lish ed and m aintained during th e grow th p eriod; to e n c o u r age arch-length dev elo p m en t to ac co m m o d ate th e full co m p lem en t o f p e rm a n en t tee th ; a n d , to d evelop a serial e x tra ctio n program involving th e early ex tra ctio n o f first p rem o lars w hen it has been d eterm in ed th a t the d iscrep an cy betw een to o th size and alv eo lar arch length is sufficient to p reclu d e norm al positioning o f th e te e th in the p e rm a n e n t dentition. E arly tre a tm e n t in th is in stan ce w as u n d e r tak en to accom plish th e first tw o objectives: in o th e r w o rd s, to develop norm al arch form and fu n ctio n , and to guide th e developing arch length so th a t all th e p erm an en t te e th , ex cep t th ird m o lars, w ould be acco m m o d ated in th e m ature arch . A n alysis o f th e case indicated th a t th e m alocclusion w as prim arily dental in origin and th at prognosis w as fav o rab le fo r elim inating th e arch-length deficiency. T h is la tte r decision w as m ost fo rtu n a te since a m ore com plex problem w ould have ensued if the first p rem o lars had been e x tra c te d as m ight have been the case if the G reenberg— O rlian: ECTOPIC MOVEMENT OF CANINE ■ 127
arch-length discrepancy had been more pro nounced. A migrating tooth will move in the direction in which the crown is pointed9 and the crown will maintain the lead during migration. Therefore, in the instance of mandibular canines, their path way of migration is mesial and, as in this case, it is possible for the tooth to unaccountably rotate from an apparently normal development posi tion to assume a horizontal intraosseous migra tion apical to the anterior teeth.
Summary A case history has been given with the radiographic evidence of the migration, during devel opment of an unerupted mandibular canine from its normal position. In a 30-month period the ca nine assumed a horizontal position and moved to a site that was apical to the mandibular inci sors, still in the confines of the cortical plates. Because erratic movements of unerupted teeth cannot be anticipated, it would seem wise to de fer the elective removal of permanent teeth dur
128 ■ JADA, Vol. 93, July 1976
ing the mixed dentition stage until the clinician is assured of a normal eruption pattern of the succedaneous teeth.
Dr. Greenberg is an orthodontist at 143-33 Sanford Ave, Flushing, NY 11355. Dr. Orlian is an oral surgeon and director of dentistry, Flushing Hospital. Address requests for reprints to Dr. Greenberg. 1. Stafne, E.C. Oral roentgenographic diagnosis, ed 2. Phil adelphia, W. D. Saunders Co., 1963, p 53. 2. Black, S.L., and Zallen, R.D. An unusual case of t’ooth migra tion. Oral Surg 36:607 Oct 1973. 3. Fiedler, L.D., and Ailing, C.C. Malpositioned mandibular right canine: report of case. J Oral Surg 26:405 June 1968. 4. Pratt, R.J. Migration of canine across the mandibular mid line. Br Dent J 126:463 May 20, 1969. 5. Stafne, E.C. Malpositioned mandibular canine. Oral Surg 16:1330, 1963. 6. Tarsitano, J.J.; Wooten, J.W.: Burditt, J.T. Transmigration of nonerupted mandibular canines: report of cases. JADA 82: 1395 June 1971. 7. Moss, M.L.; Greenberg, S.N.; and Noback, C.R. Develop mental migration of mandibular buccal dentition in man. Angle Orthod 29:169 July 1959. 8. Hutchinson, A.C. Dental and oral X-ray diagnosis. Edin burgh, E & S Livingstone, 1954, pp 46, 52, 113. 9. Sutton, P.R. Migrating nonerupted mandibular premolars: a case of migration into the coronoid process. Oral Surg 25:87 Jan 1968.
