surgical extraction of mandibular third molar in ... · surgical extraction of mandibular third...
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Surgical extraction of mandibular third molar in pterygomandibular space: a case report
Young-Kyu Lee1, Sung-Soo Park1,2, Hoon Myoung1,3
Department of Oral and Maxillofacial Surgery, 1School of Dentistry, Seoul National University, Seoul, 2Korean Armed Forces Capital Hospital, Seongnam, 3Dental Research Institute, Seoul National University, Seoul, Korea
Abstract (J Korean Assoc Oral Maxillofac Surg 2013;39:242-245)
Impacted mandibular third molars are located between the second mandibular molar and mandibular ramus. However, ectopic mandibular third molars with heterotopic positions are reported in the subcondylar or pterygomandibular space. The usual cause of malposition is a cyst or tumor, and malposi-tion without a pathology is rare. This case report described an impacted mandibular third molar in the pterygomandibular space without any associated pathology.
Key words: Third molar, Pterygomandibular space[paper submitted 2013. 8. 9 / revised 2013. 9. 9 / accepted 2013. 9. 11]
II. Case Report
A46-year-oldmalepatientvisitedtheDepartmentofOral
andMaxillofacialSurgery,SeoulNationalUniversityDental
Hospital,complainingofswellingandpainintherightpreau-
ricularregion.Hewaspreviouslytoldbyageneraldentistat
alocalclinicthathehadamalposedtoothintherightman-
dibleandwasadvisednottohavethetoothextracteduntil
symptomsappear.Apanoramicradiographshowedathird
molarlocatedhighintheascendingramusoftherightman-
dible.(Fig.1)Toidentifytheexactlocationofthetooth,com-
putedtomography(CT)wastaken,showingthethirdmolar
inthepterygomandibularspaceassociatedwitharadiolucent
lesion.(Fig.2)Theradiolucentlesionwasevaluatedascystic
lesionsuchasodontogenickeratocystordentigerouscystor
secondaryinflammationaccompaniedbysofttissueinvolve-
ment.
Thesurgerywasperformedundergeneralanesthesiavia
theintraoralapproach.Anincisionwasmadeovertheright
externalobliqueridgeandextendedfromthesecondmolar
totheposterosuperiormandibularascendingramus.Subperi-
ostealdissectionwasdonesuperiorly,exposingtheanterior
borderoftheramusfromtheretromolarareaalmosttothetip
ofthecoronoidprocess.Medialsubperiostealdissectionpro-
ceededposteriorly,exposingthelingulaandinferioralveolar
neurovascularbundleuptothecondyleneck.Osteotomywas
I. Introduction
Thesurgicalextractionofanimpactedmandibularthird
molar isoneof themostcommonproceduresperformed
byoralandmaxillofacialsurgeons.Mostmandibularthird
molarsareimpactedinthemandibularramusareanearthe
secondmolar,andthelevelofdifficultyofextractionisclas-
sifiedaccordingtothedegreeofimpaction,positioninthe
mandibularramus,andangulationofthelongaxisofteeth.
Usually,athirdmolarimpactedfarawayfromitsoriginalsite
isaffectedbyacystoratumor.Onlyafewcasesofectopic
mandibularthirdmolarintheregionofpterygomandibular
spacewithoutassociationofcysticlesion--suchasodonto-
genickeratocystanddentigerouscyst--havebeenreported1,2.
Wereportacaseofmandibularthirdmolarlocatedinthe
pterygomandibularspacethatseemstohavebeendisplaced
byneithercystnortumor.
CASE REPORThttp://dx.doi.org/10.5125/jkaoms.2013.39.5.242
pISSN 2234-7550·eISSN 2234-5930
Hoon MyoungDepartment of Oral and Maxillofacial Surgery, Dental Research Institute, Seoul National University, 101, Daehak-ro, Jongno-gu, Seoul 110-749, Korea TEL: +82-2-2072-3059 FAX: +82-2-766-4948E-mail: [email protected]
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Copyright Ⓒ 2013 The Korean Association of Oral and Maxillofacial Surgeons. All rights reserved.
Surgical extraction of mandibular third molar in pterygomandibular space
243
sitewasprimarilysutured,with4/0vicrylapplied.Thepost-
operativewoundhealingwasuneventful,withnonervedam-
agesymptom.Asmallfollicularspaceenvelopingthecrown
ofthetoothwasalsoidentified,suggestinginflamedgranula-
tiontissue.(Fig.5)Aconnectiontotheperiodontalspaceof
themandibularsecondmolarwasdetected.Inviewofthe
scleroticchangeoftheunderlyingmandible(Fig.2)andden-
talcaries(Fig.3B),weassumethattherehadbeenprolonged
communicationwiththeoralcavity.Thisultimatelyledto
theinfectiousprocess.
III. Discussion
Severalstudieshavereportedectopicmandibularthirdmo-
lar in themandibularramus3,4,mandibularcondyle5-7,and
coronoidprocess8.
The true incidenceandetiologyofectopicmandibular
thirdmolar remainunknown9.Anaberranteruptionpat-
ternhasbeensuggestedtooccurwhenthetoothhasbeen
displacedbyalesion,usuallyanodontogeniccyst3,10,11.Den-
tigerouscyst is themostcommonbenignlesionrelatedto
performedwitharoundburonthemedialsideoftheman-
dible.Thetoothwasexposedandcarefullyremoved.(Fig.
3)Thetoothwaseasilyremovedfromtheareabetweenthe
lingulaandthesigmoidnotch.Thepostoperativepanoramic
radiographshowedtheremovalofectopicmandibularthird
molar.(Fig.4)Sharpareasweresmoothened,withthesite
curettedandcleanedwithsterilesalinesolution.Thesurgical
Fig. 1. Panoramic view of ectopic mandibular third molar in the right ascending ramus of the mandible.Young-Kyu Lee et al: Surgical extraction of mandibular third molar in pterygomandibu-lar space: a case report. J Korean Assoc Oral Maxillofac Surg 2013
Fig. 2. Axial image (A) and coronal im-age (B) of computed tomography (CT). CT scans show that the mandibular third molar is located in the pterygo-mandibular space. The sclerotic change of the mandible around the mandibular third molar is consistent with chronic infection.Young-Kyu Lee et al: Surgical extraction of mandibu-lar third molar in pterygomandibular space: a case report. J Korean Assoc Oral Maxillofac Surg 2013
Fig. 3. A. Intraoperative view of the os-tectomy site in the medial aspect of the ascending ramus of the mandible. B. Removed ectopic mandibular third mo-lar whose crown was blackened.Young-Kyu Lee et al: Surgical extraction of mandibu-lar third molar in pterygomandibular space: a case report. J Korean Assoc Oral Maxillofac Surg 2013
J Korean Assoc Oral Maxillofac Surg 2013;39:242-245
244
Surgicalextractionismostlyperformedbyanintra-oral
approach.Extra-oralapproachisdoneinextremelydisplaced
impactedtoothcases.Whenteetharelocatedneartheman-
dibularcondyle,thepreauricularapproachcanbeused.The
approachhastheadvantageofgoodexposureofthesurgical
sitebutmayresultincomplicationssuchasextraoralscar,
damagetotemporomandibularjoint,andfacialnerveinjury11.
Theintraoralapproachmayavoidtheseproblems,butaccess
toandviewoftheseverelydisplacedtoothmaybelimited;
thusmakingthesurgerydifficult.Inthiscase,theimpacted
toothwaslocatedonthelingualsideofthepterygomandibu-
larspace,andthesurgerywasperformedusingtheintraoral
approach.During thesurgery, the inferioralveolarnerve
shouldbeprotected.Moreover,excessivegrindingof the
coronoidprocessormandibularcondyleshouldnotbedone
topreventfracture.
Nowadays,most thirdmolarextractionsareperformed
whenthepatientsareintheirtwenties,sothedislocationbe-
comesrarer.Moreover,theremaybepatientswithectopic
toothwithoutclinicalsymptoms,notknowingthattheyhavea
dislocatedtooth.Therefore,annualpanoramicradiographtak-
ingfromchildhoodisrecommendedfortheearlydetectionof
ectopicthirdmolaranditspathologicchangessuchascystfor-
mationandinfection.Impactedteethdiagnoseduponroutinera-
diographicexamination--andwhicharenotassociatedwithany
pathology--usuallydonotrequiretreatment,buttheyshouldbe
removedtopreventcystformation,infection,andweakeningof
thebonepredisposingtofracture7.Thesurgicalextractionofthe
ectopicthirdmolarshouldbecarefullyplannedandperformed
tominimizecomplicationsinducedbysurgery.
impactedmandibularthirdmolar12.Overtime,thepressure
exertedbytheintracysticfluidontheocclusalaspectofthe
thirdmolarmaycauseitsdisplacement,sometimesfromits
originallocation3,4,13.
In thepresentcase, themandibular thirdmolarwasnot
displacedbyacysticlesionbutbyanuncertaincause.The
developmentof the toothgerminanaberrantpositionor
aberranttoothgermeruptionpatternmaybethemostlikely
etiology.Otherwise,primaryandtotaldislocationoftooth
basemaybethecause8.Intheprocessofmandibularskeletal
growth,boneis typicallyaddedalongtheposteriorramus
borderandresorbedalongtheanteriorborder;mandibular
condyledevelopsasaresultofboneappositionintheposte-
riorramus14.Inthiscase,thepresenceofdentalcariesimplies
thattoothdislocationoccurredafteritsexposuretotheoral
cavity.
KerosandSusić8reportedtheectopicmandibularthirdmo-larinthecoronoidprocessandassumedthattheboneform-
ingthemandibularbaseinchildhoodmayshifttotheregion
beneaththecoronoidprocessinadulthood,withtheectopic
mandibular thirdmolarembedded.Following thenormal
growthpattern,thethirdmolarcrownmovedupward,even-
tuallyreachingthecoronoidprocessofthemandibleinnon-
invertedstate.
Nonetheless,theetiologyofectopicimpactionandmigra-
tionoftoothisstillunclear.Peck15reportedthattheintraos-
seousmigrationofimpactedmandibulartoothisrelatedto
geneticdeterminants.AccordingtoMarksandSchroeder16,
regionaldisturbanceinthedentalfolliclemightleadtolocal
defectiveosteoclasticfunction,withanabnormaleruption
pathwaybeingformed.Sutton17believedthatanabnormally
strongeruptionforceorachangeaffectingthecryptofthe
toothgermmightleadtoerroneouseruption.
Fig. 4. Postoperative panoramic radiograph showing the removal of the ectopic third molar in the pterygomandibular space.Young-Kyu Lee et al: Surgical extraction of mandibular third molar in pterygomandibu-lar space: a case report. J Korean Assoc Oral Maxillofac Surg 2013
Fig. 5. Histopathologic imaging (H&E, ×200).Young-Kyu Lee et al: Surgical extraction of mandibular third molar in pterygomandibu-lar space: a case report. J Korean Assoc Oral Maxillofac Surg 2013
Surgical extraction of mandibular third molar in pterygomandibular space
245
9. BortoluzziMC,ManfroR.Treatmentforectopicthirdmolarinthesubcondylarregionplannedwithconebeamcomputedtomogra-phy:acasereport.JOralMaxillofacSurg2010;68:870-2.
10. SalmerónJI,delAmoA,PlasenciaJ,PujolR,VilaCN.Ecto-pic thirdmolar incondylar region. IntJOralMaxillofacSurg2008;37:398-400.
11. WangCC,KokSH,HouLT,YangPJ,LeeJJ,ChengSJ,etal.Ec-topicmandibularthirdmolarintheramusregion:reportofacaseandliteraturereview.OralSurgOralMedOralPatholOralRadiolEndod2008;105:155-61.
12. Suarez-CunqueiroMM,SchoenR,SchrammA,GellrichNC,SchmelzeisenR.Endoscopicapproachtoremovalofanectopicmandibularthirdmolar.BrJOralMaxillofacSurg2003;41:340-2.
13. SzerlipL.Displacedthirdmolarwithdentigerouscyst--anunusualcase.JOralSurg1978;36:551-2.
14. BuschangPH,GandiniJúniorLG.Mandibularskeletalgrowthandmodellingbetween10and15yearsofage.EurJOrthod2002;24:69-79.
15. PeckS.Onthephenomenonofintraosseousmigrationofnonerupt-ingteeth.AmJOrthodDentofacialOrthop1998;113:515-7.
16. MarksSCJr,SchroederHE.Tootheruption:theoriesandfacts.AnatRec1996;245:374-93.
17. SuttonPR.Migrationanderuptionofnon-eruptedteeth:asug-gestedmechanism.AustDentJ1969;14:269-70.
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