growth rotations of mandible final.pdf

growth rotations of mandible

1. GROWTH ROTATIONS
PRESENTED BY
DR.ABHISHEK GOURISHETTY
PG 1
ST
YEAR
DEPT OF ORTHODONTICS AND DENTOFACIAL
ORTHOPAEDICS
1

2. CONTENTS
INTRODUCTION
MANDIBULAR GROWTH ROTATIONS
BJORKS CLASSIFICATION
BJORK AND SKIELLERS METHOD
SCHUDYS CONCEPT
DIBBETS CONCEPTS
ENLOWS CONCEPT
PROFFITS CONCEPT
GROWTH ROTATIONS OF MAXILLA
STUDIES ON GROWTH ROTATIONS
REFERENCES
2

3. INTRODUCTION
Thephrasegrowthrotationwasintroducedin1955byDRARNEBJORK.
Hedescribeditasaphenomenonoccurringduringgrowthofthehead.
Thetechniqueofinsertingmetalimplantsintothebonehasbeenusedinanimalsformore
thanacenturybutapplicationofthismethodwasrecentinhumans.
Metallicimplantshavebeeninsertedinthejawstoserveasafixedreferencepoints.
3

4. Implant radiology
Bjorkstartedhisstudyin1951andhadsamplesizeof100childrenbetweenagegroupsof4
and24years.
Thesampleconsistsofnormalchildrenwithandwithoutmalocclusion.
Usedmetalimplantstofindthesitesofgrowthandresorptioninindividualjaws.
Alsoexaminedindividualvariationsindirectionandintensity.
Analysedmechanicsofchangesinintermaxillaryrelationshipduringgrowth.
4

5. 5
Variations in the Growth Pattern of the Human Mandible:
Longitudinal Radiographic Study by the Implant Method
ARNE BJORK 1963

6. Mandible
rotation
Forward
Type I Type II Type III
Backward
Type I Type II
6
Bjorksclassification

7. Forward rotation
TypeI
Centre of rotation is the TMJand deep bite is seen.
Lower dental arch is pressed into upper
Under development of anterior face height.
Cause due to occlusal imbalance due to loss of teeth pressure
And also due loss of muscular pressure
7

8. Forward rotation
Type II
Centreisattheincisaledgeoflowerincisor
Combination-normalincreaseinanteriorheightmarkedincreasein
posteriorfacialheight
Increasedposteriorfaceisdueto-
1)Bendingofcranialbase-loweredmiddlecranialfossacomparedto
anteriorandcondylarfossaislowered
2)Increaseinramusheight-verticalgrowthatcondyle
8

9. Forward rotation
Type III
Centreislocatedatthepremolars.
Seeninlargemaxillaryormandibularoverjetcases.
Anteriorfacialheightisunderdeveloped
Increaseinposteriorfacialheight.
Skeletaldeepbiteisseen.
9

10. Backward rotation
Type 1 -Centre is at the TMJ.
Seenwhenbiteisraisedbyorthodontictreatment.
10
Flat cranial
base
Mandible is
raised
Posterior
face is under
developed
Mandible
rotates
backward
Anterior face
is over
developed
Open bite

11. Backward rotation
TypeII
Growthatcondylesisseensagittally
11
Centre of
rotation at
molars
Symphysis
swings
backward
Chin drawn
below face
Basal open
bite
Difficulty in
closing the
lips

12. Clinical implications
Theserotationsinfluencesthepathoferuption.
Crowdinginmandibleisresultsfrombothdirectionsofrotations.
Inforwardrotationdeepbiteisseenandinbackwardrotationopenbiteisseen
Extractionsshouldbeavoideduntilbeginningofpubertalgrowthspurt.
12

13. Bjork structural signs
Bjorkgavesevenstructuralsignstofindthedirectionofcondylargrowth.
1)Condylarinclination
2)Mandibularcanalinclination
3)Lowerborderofmandible
4)Symphysisinclination
5)Interincisalinclination
6)Intermolarangle
7)Lowerfaceheight
13

14. Allofthemarenotfoundinaparticularindividual.
Butgreaterthenumbermorereliabilityoftheprediction.
Thesesignsarenotclearlydevelopedbeforepuberty.
14
PREDICTION OF MANDIBULAR GROWTH ROTATION BJORK Am J Orthod1969

15. Condylar inclination
Forward or backward inclination of condylar head is characteristic sign.
In forwardgrowing mandible condyle is upright
In backwardgrowing mandible it is inclined backward.
It is difficult to identify on a lateral cephalogram.
15

16. 16

17. Mandibular canal
Inverticallygrowersthecurvatureof
thecanalismorethanthatof
mandibularcontour.
Inhorizontalgrowersthecanalisflat
ormaybecurvedinoppositedirection
17

18. Shape of lower border of mandible
Inverticalgrowersthereisincreaseddepositionbelowthesymphysis.
Anteriorpartofmandiblebecomesthickalongwithresorptionattheangle
producingcharacteristicconcavity.
Inhorizontalgrowerstheanteriorroundingisabsentsotheconcavityoflower
borderisabsent.
18

19. 19

20. Inclination of symphysis
Inverticaltypesymphysisswingsforwardandchinbecomesprominent.
Inhorizontalgrowersitswingsbackwardcausingarecedingchin.
20

21. Inter incisal angle
21
Inverticalgrowersinterincisalangleisless.
Inhorizontalgrowerstheinterincisalangleismore.
Intermolarangle
Incaseofforwardrotationthemolarsgetmoreuprightincreasingtheintermolarand
interpremolarangle.
Whileincaseofbackwardrotationthemolarsbecomemesiallytippedhencedecreasing
theintermolarandinterpremolarangle.

22. 25

23. Lower anterior facial height
Increased in case of vertical growth pattern which is less in case of horizontal growth
pattern.
23

24. Bjork and Skiellersmethod
BjorkandSkiellersubsequentlytogethercarriedouttheextensiveimplantstudies
andintroducedvariousterminologiestounderstandtherotationalpatternofthe
mandible.
Dividedrotationinto3components
1)Totalrotation
2)Matrixrotation
3)Intramatrixrotation
29

25. Total rotation
Rotationofmandibularcorpusisseen
Measuredasachangeininclinationofanimplantline
inthemandibularcorpusrelativetotheanterior
cranialbase.
25
The puzzle of growth rotation dibbetsAm J Orthod1985

26. Matrix rotation
Rotation of soft tissue matrix of the mandible relative to the
cranial base.
The soft tissue matrix is defined by tangential mandibular
line.
Centre of rotation is at the condyles
26
Mandibular rotation revisited;whatmakes it so important? Buschang
seminars in orthodontics 299-315 ,2014

27. Intra matrix rotation
Thedifferencebetweenthetotalrotationandthematrix
rotationisanexpressionoftheremodelingatthelower
borderofthemandible.
Changeininclinationofanimplantorreferencelinein
themandibularcorpusrelativetothetangential
mandibularline.
27

28. Bjorkandskiellersaidthatthreechangesoccurringinintramatrix
rotation-
1)Themandiblewigglesinitsmatrix.
2)Thiswigglingisassociatedwiththecorpusbutiscausedbygrowing
condyle.
3)Therotationresultsfromorcompensatesforgeneticallypredetermined
program.
28
The puzzle of growth rotation by DibbetsAm J Orthod1985

29. Lavergneand Gasson
Mandibularrotationsareoftwotypes-
1)Morphogeneticrotation–concernstheshapeofthemandible.
2)Positionalrotation–dealswiththepositionofmandiblewithinthehead.
Inthisproceduretwosuccessivecephalogramssuperimposedonalinethrough
condylionandpogonion
Thentheanglebetweenthetwoimplantlinesisdeterminedandthiscorrespondsto
degreeofmorphogeneticrotation.
29

30. 30
Analysis and Classification of the Rotational Growth Pattern Without
Implants J. Lavergne& N. GassonBritish journal of orthodontics 1982

31. Schudysconcept
AccordingtoSchudytherotationofthemandibleistheresultofdisharmonybetween
verticalgrowthandanteroposteriororhorizontalgrowthofjaws.
31
Mandibular
rotation
Clockwise rotation
Counter clockwise
rotation
THE ROTATION OF MANDIBLE RESULTING FROM ITS GROWTH ITS IMPLICATIONS
AND ORTHODONTIC TREATMENT BY SCHUDY ANGLE ORTHODONTIST 1965

32. Clockwise rotation
Moreposteriorverticalgrowththancondylargrowth.
Pointofrotationisthecondyle.
Pogonioncannotkeepupwithforwardgrowthofupperface
Mandibularplanebecomessteeper
Extremesofthisconditioncausesopenbite
32

33. 33

34. Counter clockwise rotation
Duetomorecondylargrowththanverticalgrowth.
Forwardmovementofpogonionandincreaseinfacialangle.
Pointofrotationisthemostdistalmandibularmolarinocclusalcontact.
34

35. Flatteningofmandibularplaneincreasetheverticaloverbite.
Smallerthegonialanglethegreatertherotationproducedformmof
forwardmovementofpogonion.
Extremesofthisconditioncausesclosedbite.
35

36. 36

37. 1.Fourverticalgrowthelementswhichincreasefacial
height
37
Growth at nasion
Growth of maxillary posterior alveolar process
Eruption of maxillary molars
Eruption of mandibular molars

38. Schudystatesthatthemandibleshouldnotbeconsideredasasinglegrowth
entity,butas4entities:-
1)Growthofthecondyleandramus
2)Growthofthebodyofmandible
3)Growthoftheposterioralveolarprocess
4)Growthoftheanterioralveolarprocess
38

39. 39

40. Dibbetsconcept
Hehypotheticallyconstructed2possibledivergentpatternsofthemandibulargrowth
Circularpattern-postulatescondylargrowthasasegmentofacirclewithitscentreatthe
chin.
Thewholemandiblewouldthenrotatearounditselfwithinitsperiostealcontours,resultingin
intramatrixrotationwithoutenlargementofthemandible.
Linearpatternofthecondylewithoutanyintramatrixrotationandmaximumenlargementof
themandible.
40
THE PUZZLE OF GROWTH ROTATION BY DIBBETS Am J Orthod1985

41. 41
MANDIBULAR ROTATION AND ENLARGEMENT BY DIBBETS Am J Orthod1990

42. 42
PUZZLE OF GROWTH ROTATION DIBBETS Am J Orthod1985

43. DibbetintroducedtheconceptofCounterbalancingrotationwhichtriestooffset
condylargrowthincrementswhichwouldthrowthemandibleoutofitsestablished
equilibriumwithitsassociatedskeletalunits(maxilla).
SoCounterbalancingrotationisamechanismthat
1)Neutralizesgrowth
2)Resultsinenlargementofmandible
43

44. Enlowsconcept
Primarydisplacement
Thewholenasomaxillarycomplexisdisplacedduetoits
owngrowth
Secondarydisplacement
Resultsfromgrowthofotherbonesandsofttissues
44

45. 45
Proffit’s
classification

46. 46
CONTEMPORARY ORTHODONTICS 6 TH EDITION -WH PROFFIT

47. 47

48. Clinical importance
Shortfacetype
1)Shortanteriorlowerfaceheight
2)Excessiveforwardrotationofmandibleduringgrowth
3)Increasednormalinternalrotationanddecreasedexternal
compensation
4)Deepbiteandcrowdingofincisors
48
CONTEMPORARY ORTHODONTICS 6 TH EDITION -WH PROFFIT

49. Longface
1)Increasedloweranteriorfaceheight
2)Palatalplanerotatesdownposteriorly
3)Increasedmandibularplanebecauseofbackwardrotationof
mandible
4)Anterioropenbite
5)Mandibulardeficiencyduetorotationofchinbackwardand
downward
49

50. 50

51. Growth prediction
AccordingtoBjorkthreemethodsofprediction-
a)Longitudinalmethod-courseofdevelopmentbyannualxraycephalograms.
b)Metricmethod–aimsatpredictionbasedonmetricdescriptionoffacialmorphologyata
singlestagedevelopment.
c)Structuralmethod–basedoninformationoftheremodelingprocessofthemandibleduring
growthgainedfromimplantstudies.
51
Prediction of mandibular growth rotation Bjork Am J Orthod1969

52. Growth rotations of maxilla
52
BjorkandSkiellerin1977conductedastudytoanalysegrowthofthemaxilla
usingimplantmethodfromprofileandfrontal(postero-anterior)cephalometric
radiographs.
Theyfoundtwotypeofrotationsofmaxilla
1)Verticalrotation
2)Transversemutualrotation
GROWTH OF MAXILLA IN THREE DIMENSIONS AS REVEALED RADIOGRAPHICALLY BY
IMPLANTS METHOD BJORK AND SKIELLER 1977 BRITISH JOURNAL OF ORTHODONTICS

53. Vertical rotation
53
Superimpositionoflongitudinalprofileradiographsonthenasion-sellalineshowsgenerally
analmostparallelloweringofthenasalfloor,asdescribedbyBrodiein1941.
Thisobservationledtotheviewthatduringgrowththemaxillaisloweredwithoutrotationin
theverticalplane.
Butimplantstudies(BjorkandSkieller,1972)haveshownthatthedownwardandforward
displacementofthemaxilladuringgrowthisassociatedwithavaryingdegreeofvertical
rotation,directedforward.

54. Transverse rotation
Wecomparetheincreaseinwidthbetweentheanteriorandthelateralimplants.
Sincerightandleftmaxillaearetwoseparatebones,joinedalongthemediansuture,thereis
ananteriorandalateralimplantineachmaxilla.
ThereisanincreaseinwidthfromtheageofI0-11years,measuredbetweenthelateral
implants,was,onanaverage,threeandahalftimesasgreatasthatbetweentheanterior
implants.
54

55. Thatthelateralimplantsseparatemorethantheanteriorduringthegrowthindicatethatthetwo
maxillaerotateinrelationtoeachotherinthetransverseplane.
55
BJORKANDSKIELLER–GrowthinwidthofmaxillabyimplantmethodScandJPlastReconstrSurg8:26-33,11974

56. Referencepointsinmaxillaare
1)Inferiortotheanteriornasalspine(anteriorimplant)
2)Thezygomaticprocessofthemaxilla(lateralimplant)
3)Atthejunctionofthehardpalateandthealveolarprocess
medialtothefirstmolar
56

57. Mutual rotation of jaw bases
Fourtypesofmutualrotationofjawbaseswereproposedby
LavergneandGassonafterimplantstudiesin1982
Convergentrotation
Closingofmaxillo-mandibularplaneangles
Creatingaseveretruedeepbite
Bothmaxillaandmandibleconvergetowardseachother
57

58. Divergentrotationofjawbases
Maxillaandmandiblemoveawayordivergefromeachother
Leadstotheopeningofthebasalangleandresultinopenbite
problems.
Extremecasesrequiresurgicalcorrection
58

59. Cranialrotationofmaxillaandmandible
Boththemaxillaandmandiblerotatesupwardandforward.
Rotationofmaxillaoccursupwardandforwardand
compensatesforcraniallyrotatingmandible,offsettinga
deepbite.
Normaloverbiterelationship
59

60. Caudalrotationofmaxillaandmandible
Boththemaxillaandmandiblerotatedownwardand
backward.
Downwardandbackwardmaxillaryrotationoffsetstheopen
bitecreatedbydownwardandbackwardmandibularrotation
60

61. Studies on growth rotations
Variousmethodsandstudieshavebeendescribedtopredictthedirectionandamountof
growthrotationofthemandible.
Skieller,ArneBjork&LindeHansenMethod-1984.
Thisisalongitudinalcephalometricstudyusingimplants.
21Danishchildrenwerechosenwhoneverhadorthodontictreatment.
Implantswereplacedatspecificsitesinthemandibleandwerefollowedforsixyears.
64

62. Totallytwocephalometricxraysweretaken.
Thefirstonewasthreeyearsbeforethepubertalgrowthspurtandthesecondwas
threeyearsafterit.
ChangesintheinclinationoftheimplantwithrespecttotheNSLhavebeen
designatedasnegativewhentheimplantlinerotatedforwardandpositivewhenit
rotatedbackward.
62
PREDICTION OF MANDIBULAR GROWTH ROTATIONS;ASSESSSMENT OF THE SKIELLER JORK
AND LINDE HANSEN METHOD AMJ ORTHODONTICS 1998

63. 63

64. Initiallytheychose44morphologicvariablesinthemandibleforsuperimposition.
Fromthemfourwereusedwhichincombinationgavethebestprognosticestimateofthe
mandibulargrowthrotation.
Mandibularinclinationrepresentedby3alternatives:-
Index1-Proportionofposterior&anteriorfaceheight.
Lowergonialangle
Lowerborderinclination.
64

65. Intermolarangle
Shapeofthelowerborder
Symphysisinclination
Index1wasmoreaccuratethantheothertwoandwaschosenasthefirstindependent
variable.
Thiswascorrelatedwith2
nd
,3
rd
,4
th
variable&wasfoundthatthecombinationgavethebest
prognosticestimateofmandibularrotation.(86%)
65

66. Method by Todd,RamS Nanda,FransCurrier.
Thepurposeofthisstudywastodeterminewhethersymphysismorphologycouldbeusedas
predictorofdirectionofmandibulargrowthrotation.
115lateralXrayswereused.
Themandibularsymphysisdimensionsstudiedinclude-
Symphysisheight
Symphysealdepth
Symphysealangle
Height:Depthratio
66

67. AtangentisdrawnthroughB.
Agridwasconstructedwiththelinesofitparallelandperpendiculartothetangent.
ThesuperiorlimitofthesymphysiswastakenatBandmostinferior,superior,anteriorand
posterioroutlineofthesymphysisaremarkedandgridwascompleted.
Thesymphysisheightwasthedistancefromthesuperiortotheinferiorlimitofthegrid.
67

68. 68

69. Thesymphysisdepthwasthedistancefromtheanteriortotheposteriorlimit.
ThesymphysealangleisformedbetweenthelinespassingthroughB&menton&
mandibularplane.
The115adultsareseparatedintogroupsbasedongenderandthe4symphyseal
measurementsaredividedintosmall,average&largegroups.
69
Assessmentofsymphysismorphologyasapredictorofthe
directionofmandibulargrowthToddAkiRamSNandaCurrier
SurenderkNandaAJO-DO1994

70. Thedirectionformandibulargrowthfortheindividualswasevaluatedby7cephalometric
measurements:-
Yaxis
Sumofsaddle,articulare,gonialangle
SN–Mandibularplane
Lowerfaceheightpercentage
Palate–Mandibularplane
Posteriortoanteriorfaceheight
Gonialangle
70

71. Inferences
Mandiblewithanteriorgrowthrotationwasassociatedwithasmallheight,large
depth,smallratio,largesymphysisangle.
•Posteriorgrowthrotationwasassociatedwithlargeheight,smalldepth,increased
ratio,smallsymphysisangle.
•Menhaveastrongerrelationbetweensymphysismorphology&directionof
mandibulargrowththanwomen.
71

72. Observations by Petrovicand Stutzman
Amandibularalveolarbonewhichwasorganculturedforthreedaysshowedthattheboneturnover
adjacenttothemandibularfirstpremolarismoreintheanteriorgrowthrotation.
Soiforthodonticforcesareapplied,themagnitudeoforthodonticallyinducedincreaseinalveolar
boneishighinanteriorlyrotationmandible.
Alveolarboneformationisgreateronmesialsideandresorptionismoreondistalsideinanteriorly
rotatingmandible.Premolarundergoesphysiologicaldistalizationthanmesialization
Inposteriorlyrotatingmandiblefirstpremolarsundergomesialization.
72

73. References
1)ARNEBJORK-VariationsintheGrowthPatternoftheHumanMandible:LongitudinalRadiographic
StudybytheImplantMethodvol42400-411,1963
2)BJORK–PredictionofmandibulargrowthrotationAmJOrthodontics1969
3)BJORK-Cranialbasedevelopmentafollowupxraystudyoftheindividualvariationingrowth
occurringbetweentheagesof12and20yearsanditsrelationtobraincaseandfacedevelopment1952
4)DIBBETS–ThepuzzleofgrowthrotationAmJOrthodontics1985
5)LAVERGNEandGASSON–analysisandclassificationofrotationalpatternwithoutimplantsBritish
journaloforthodontics1985
6)SCHUDY-therotationofmandibleresultingfromitsgrowth;itsimplicationsandorthodontictreatment
Angleorthodontist1965
7)DIBBETS–MandibulargrowthandenlargementAmJ1990
73

74. 8)ENLOWS–Essentialsoffacialgrowth
9)Contemporaryorthodontics-WHPROFFIT
10)BJORKANDSKIELLER–Growthofmaxillainthreedimensionsasrevealedradiographicallyby
implantmethod1977Britishjournaloforthodontics
11)BJORK–FacialgrowthinmanstudiedwithaidofmetallicimplantsActaOdontologicaScandinavica
1955.
12)PredictionofmandibulargrowthrotationsassessmentofSkiellerJorkandLindeHansenmethodAmJ
Orthodontics1988
13)TODDAKIRAMSNANDASURENDERKNANDACURRIER–Assessmentofsymphysis
morphologyasapredictorofdirectionofmandibulargrowthAJODO1994
14)BUSCHANG-Mandibularrotationrevisited;whatmakesitsoimportant?seminarsinorthodontics299-
315,2014
15)BJORKANDSKIELLER–Growthinwidthofmaxillabyimplantmethod1974
74