Post-natal Growth of Maxilla and Mandible

Post-natal Growth of Maxilla and Mandible

1. POST-NATAL GROWTH OF
MAXILLA AND MANDIBLE
DR.DHARATI PATEL
NPDCH
1

2. Post-Natal growth of the
cranial base
Themaxillaisattachedtocranialbasebymanysutures
AndmandibleisattachedbyTMJ
Thusgrowthprocessesoccurringatthecranialbasecan
affecttheplacementofmaxillaandmandible
2

3. The cranial base grows by 3
growth process
1.Extensive corticle drift and remodelling
2.Elongation of synchondroses
3.Sutural growth
3

4. Corticle drift and remodelling
Aprocesswherebonedepositionandresorptionoccurs
soastobringaboutchangeinsize,shapeand
relationshipofthebone
Thecraniumbonehasbonyridgesandbonyelevations.
Thisbonyridgesandelevationshowbonedepositionand
floorshowsboneresorption.
Thisresorptionhelpsincreasestheintracranialspaceto
accommodatethegrowingbrain
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5. Elongation at synchondroses
Most of the cranium bones are formed by cartilageous process –later
cartilage is replaced by bone
However certain bands of cartilage remain at the junction of bones –
are called synchondroses
They are important growth sites of the cranial base.
The important synchondroses are
1.Spheno-occipital synchondroses
2.Spheno-ethmoidsynchondroses
3.Inter-sphenoid synchondroses
4.Inter –occipital synchondroses
5

6. Sutural Growth
The cranial base has a number of bones that are joined to one
another by means of sutures.
As the brain enlarges during growth, bone formation occurs at the
ends of the bone ( either ends of the suture)
Some of the sutures presents include:
1.Spheno-Frontal
2.Fronto-temporal
3.Spheno-ethmoid
4.Fronto-ethmoid
5.Fronto-Zygomatic
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7. Post natal growth of Maxilla 7

8. Growth Of Nasomaxillary Complex Is
Produced By Following Mechanism
Displacement
Growth at
suture
Surface
remodeling
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9. MECHANISM OF BONE GROWTH
Displacement
Movementofwholeboneasaunit
1)PrimaryDisplacement
2)SecondaryDisplacement
BoneRemodeling
Combinationofbonedepositionandresorptionresultingin
growthmovementtowardsdepositionsurface
Growthatsuture

10. Displacement
•The process of physical carry, takes place in
conjunction with a bone’s own enlargement.
Primary displacement
•The movement of bone and its soft tissues is
not directly related to its own enlargement.
•It is a fundamental part of the overall
process of craniofacial enlargement.
Secondary displacement
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11. 11

12. Primary displacement
Seeninforwarddirection
Occursbygrowthofmaxillarytuberosityinposteriordirection
Thisresultinthewholemaxillabeingcarriedanteriorly.
Theamountofthisforwarddisplacementequalstheamountof
posteriorlengthening.
Thisisaprimarytypeofdisplacementastheboneisdisplaced
byitsownenlargement.
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13. 13

14. Secondary displacement
Maxillaisattachedtothecranialbasebymanysutures.
TheNaso-maxillarycomplexismovedanteriorlyasthe
MiddleCranialfossagrowsinanteriordirection
Movement–indownward&forwardsdirection
Thepassivedisplacementismoreimportantduringprimary
dentitionyearsbutbecomeslessimportantasgrowthof
cranialbaseslows.
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15. 15

16. Growth at suture
The maxilla is connected to the cranium and the cranial
base by a number of sutures.
These sutures include
Fronto-nasal suture
Fronto–maxillary suture
Zygomatico–maxillary suture
Pterygo–palatine suture
Zygomatico –temporal suture
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17. 17

18. Suturesareobliqueandparalleltoeachother
Thisallowsdownwardandforwardrepositioningofthemaxilla
asgrowthoccursatthesesuture.
Asgrowthofsurroundingsofttissueoccurs,themaxillais
carriesdownwardandforward.
Thisleadstoopeningupofspaceatthesuturalattachments.
Newboneisnowformedoneithersideofsuturespace-the
overallsizeofboneincreases
Hencetensionrelatedboneformationoccuratsuture
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19. 19

20. Surface Remodeling
Massiveremodelingbybonedepositionandresorption
occurstobringbout
Increaseinsize
Changeinshapeofbone
Changeinfunctionalrelationship
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21. 21

22. Bone remodelling changes that are
seen in NMC
Bonedeposition–posteriormarginofmaxillary
tuberosity.Thiscauselengtheningofthedentalarch.This
helpstoaccommodatetheeruptingmolars.
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23. Orbital growth 23
Resorptiononlateralsurfaceleads
tolateralmovementofeyeball
Tocompensatethisthereisbone
depositiononthemedialrimofthe
orbit
Tomakethesupra-orbitalrimmore
prominentbonedepositionoccurs
atAnterior–lateral-superior
direction

24. The nasal cavity 24
Boneresorption–onlateralwall-
increaseinsizeofnasalcavity
Boneresorption-floorofnasal
cavity–tocompensatebone
depositiononpalatalside
Thusanetdownwardshiftoccurs
leadingtoincreaseinmaxillary
height

25. The zygomatic arch
TheZygomaticboneMovesinaposteriordirection
byresorptiononanteriorsurfaceanddepositionon
posteriorsurface
Faceenlargedinwidthbyboneformationatlateral
surfaceofarchandresorptiononmedialsurface
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26. Palatal remodeling
Anteriorly-labialsideis
Resorptiveandpalatalsideis
depositorycauseswideningof
palateacctoVprinciple
Growthatmidpalatalsutureplays
aroleintheprogressivewidening
ofthepalateandalveolararch
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27. Maxillary sinus
Allinternalsurfacesare
resorptiveexceptmedial
nasalwall
Resultsinincreaseinsize
ofantrum.
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28. Vertical drift of teeth
Astheteethstartstoerupt
Bonedepositionoccuratalveolarmargin
Increasemaxillaryheightanddepthofpalate
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29. Functions of Nasomaxillary
complex
1.Mastication.
2.Providessignificantportionoftheairway.
3.Containsphysiologicallyimportantnasalmucosawith
theirglandsandtemperatureadjustingvascular
components.
4.Separatesnasalfromoralcavities.
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30. 5.Housesolfactorynerveendings,encloseseyes.
6.Addresonancetothevoicebecauseofsinuscontained
withintheregion.
7.Alongwithadoptionwithbasocraniumandattachment
withmandiblefunctionsinmastication,speech,facial
expression,respirationetc.
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31. AGE CHANGES IN
MAXILLA AT BIRTH
Thetransverseandantero-posteriordiametersare
morethantheverticaldiameter.
Frontalprocessiswellmarkedatbirth
Thetoothsocketsreachingtotheflooroforbit
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32. IN ADULT
Verticaldiameterisgreatestduetothedevelopment
ofthealveolarprocessandincreaseinthesizeof
thesinus.
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33. IN THE OLD
Thebonerevertstoinfantilecondition
Itsheightisaresultofabsorptionofthealveolar
process.
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34. Clinical implication
ClassII(excessivemidfacegrowth)
ClassIII(decreasedmidfacegrowth)
Maxillaryexcessivegrowthcanbereducedby
maturationandincreasedtonicityofperioralsoft
tissue.E.g.Functionalappliance
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35. Cleftlip(cheiloschisis)andcleftpalate(palatoschisis),whichcan
alsooccurtogetherascleftlipandpalate,arevariationsofa
typeofcleftingcongenitaldeformitycausedbyabnormalfacial
developmentduringgestation.
It’scommonsiteforsinglemostcommoncraniofacialanomaly
Itoccursduetothefailureoffusionofthelateralpalatine
processes,thenasalseptum,and/orthemedianpalatine
processes
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36. Genesis of cleft palate
Delay in shelf elevation
Disturbance in mechanism of shelf elevation
Failure of shelves to contact due to lack of growth
Failure to displace the tongue during closure
Failure to fuse after contact as epithelium does not
break down
Rupture after fusion
Defective merging
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37. COMPLICATIONS OF IT
Cleftmaycauseproblemswithfeeding,eardisease,
speechandsocialization.
Aninfantwithacleftpalatewillhavegreatersuccess
feedinginamoreuprightposition.
Gravitywillhelppreventmilkfromcomingthroughthe
baby'snoseifhe/shehascleftpalate.
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38. MAXILLARY HYPOPLASIA
Maxillaryhypoplasiaisthenamethatdentistshave
giventotheunderdevelopmentofthemaxillary
bones,whichproducesmidfacialretrusionand
createstheillusionofprotuberanceofthelowerjaw.
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39. Post-Natal Growth of
Mandible
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40. Ofthefacialbones,themandibleundergoesthelargest
amountofgrowthpostnatallyandalsoexhibitsthelargest
variabilityinmorphology
Thebasalboneorthebodyofmandibleformsoneunit,to
whichisattachedthealveolarprocess,thecoronoid
process,thecondylarprocess,theangularprocess,the
ramus,thelingualtuberosityandthechin.
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41. POST NATAL GROWTH AND
DEVELOPMENT GROWTH
TIMING
Growth of widthof mandible is completed first
then growth in lengthand
finally growth in height
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42. WIDTH OF MANDIBLE
Growthinwidthiscompletedbeforeadolescentgrowth
spurt
Inter-caninewidthdoesincreaseafter12years
Bothmolarandbicondylarwidthshowssmallincrease
untilgrowthinlengthends
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43. GROWTH IN LENGTH
Growth in length continues through puberty
Girls -14-15 years
Boys -18-19 years
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44. MAIN SITES OF POST NATAL
GROWTH IN THE MANDIBLE
Growth of
mandible
Alveolar
ridges
Posterio
r border
of the
Rami
Condylar
cartilage
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45. 1.Ramus
Itprovidesanattachmentbaseformasticatory
muscles.
Movesprogressivelyposteriorlyby
Deposition–PosteriorPart
Resorption–AnteriorPart
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46. Superior part of
ramus below
sigmoid notch
Lingual –
deposition
Buccal -
resorption
Lower part of
ramus below the
coronoid process
Buccal -
deposition
Lingual -
resorption
46

47. 47

48. The functions of remodelling
of the ramus
Toaccommodatetheincreasingmassofmasticatory
musclesinsertedintoit
Toaccommodatetheenlargedbreadthofthepharyngeal
space
Tofacilitatethelengtheningofthebodyofthemandible
–toaccommodatetheeruptingmolars
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49. 2. Body of the mandible
Bodyofthemandiblelengthensastheramusexhibits
bonedepositionontheposterioraspectandresorptionon
theanterioraspect
Inthismannerbodyofthemandiblelengthens
Whichhelpinaccommodationoftheeruptingpermanent
molars
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50. 50

51. 3. Angle of the mandible
Lingual side
Posterio-
inferior aspect
Resorption
Anterio-
superior aspect
Deposition
Buccal side
Anterio-
superior aspect
Resorption
Posterio-
inferior aspect
Deposition
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Thisresultinflaringoftheangleofthemandible

52. 4. Lingual tuberosity
Majorsiteofmandibulargrowthandremodeling.
Directanatomicequivalentofthemaxillarytuberosity.
Growsposteriorlybydepositsontheonitsposteriorsurface
Itsprominenceisaugmentedbythepresenceofaresorptive
fieldbelowit-sizabledepression-lingualfossa.
Simultaneouslythepartoftheramusbehindthetuberosity
remodelsmedially
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53. 53

54. 5. Alveolar process
Alveolarprocessdevelopsinresponsetothepresenceof
toothbuds.
Astheteetheruptthealveolarprocessdevelopsand
increasesinheightbybonedepositionatthemargins
Thealveolarprocessaddstotheheightandthicknessofthe
bodyofthemandibleparticularly.
Incaseofabsenceofteeth,thealveolarbonefailsto
developanditresorbsintheeventoftoothextraction
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55. 55

56. Mental foramen position as
age
At birth -Near the lower border
Adult –Midway
Elderly -Near the upper border
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57. 57

58. 6 . CHIN
Ininfancy–underdeveloped
Asageadvance–growthofchin–moresignificant
Influencedby–specificgeneticfactors
Maleshavemoreprominentchinthanfemale
Thisprominenceaccentuatedbyresorptionthatoccursinthe
alveolarregionaboveit-creatingconcavity.
Thedeepestpointinthisconcavityisknownas–POINTB
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59. 59

60. Coronoid process
Followstheenlarging“V”principle
Viewingthelongitudinalsectionofthecoronoidprocessfrom
theposterioraspect,depositionoccursonthelingualsurfaces
oftheleftandrightcoronoidprocess.
Viewingitfromtheocclusalaspect,thedepositiononthe
lingualofthecoronoidprocessbringsaboutaposteriorgrowth
movementinthe“V”pattern.
Depositsofboneonthelingualsurfacebringaboutgrowth
superiorly,posteriorlyandmedially.
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61. 61

62. THE CONDYLE
Majorsiteofgrowthwithconsiderableclinicalsignificance.
Headofthecondyle–coveredby–thincartilage–
CONDYLARCARTILAGE
Cartilageisnonvascular,hydrophilicandpressuretolerant.
Thepresenceofthecondylarcartilageisanadaptationto
withstandthecompressionthatoccursatthejoint.
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63. Role of growth of condyle
1.Theory-1
EarlieritwasbelievedthatGrowthoccursatsurfaceof
thecondylarcartilageby–bonedeposition
Thusthecondylegrowstowardscranialbase.
Asthecondylepushesagainstthecranialbase,the
entiremandiblegetsdisplacedforwardanddownward.
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64. 2. Theory -2
Nowitisbelievedthatthegrowthofsofttissuesincluding
themusclesandconnectivetissuescarriesthemandible
forwardsawayfromthecranialbase.
Bonegrowthfollowssecondarilyatthecondyletomaintain
constantcontactwiththecranialbase.
Condylargrowthrateincreasesatpubertyreachingapeak
between12.5–14years.
Thegrowthceasesaround20yearsofage.
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65. 65

66. AGE CHANGES IN MANDIBLE
InInfants&Children
Thetwohalvesofmandiblefuseduringthefirstyearoflife.
Atbirth,thementalforamen,opensbelowthesocketsforthetwo
deciduousmolarteethnearthelowerborder.
Thisisbecausetheboneismadeupofonlythealveolarpartwith
teethsockets.
Themandibularcanalrunsnearthelowerborder
Theforamenandcanalgraduallyshiftupwards.Lowerjawof
childandadult,showingthementalforamen.
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67. IN ADULTS
Thementalforamenopensmidwaybetweentheupper
andlowerbordersbecausethealveolarandsubalveolar
partsoftheboneequallydeveloped.
Themandibularcanalrunsparallelwiththemylohyoid
line.
Theanglereducestoabout110or120degreesbecause
theramusbecomesalmostvertical
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68. IN OLD AGE
Teethfalloutandalveolarborderisabsorbed,sothatthe
heightofthebodyismarkedlyreduced.
Thementalforamenandthemandibularcanalareclose
tothealveolarbone.
Theangleagainbecomesobtuseabout140degrees
becausetheramusisoblique.
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69. Developmental defects
Agnathia
Micrognathia
Macrognathia
Facial hemiatrophy
Facial hemi hypertrophy
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70. Conclusion
Itisimportantforthecliniciantoknowthenormaland
theabnormalrangesofgrowthforproperdiagnosis,
treatmentplanningandselectingappropriateclinical
procedures.
Orthodontictreatmentirrespectiveofappliance
dependstoagreatextentonadaptivecapacityof
alveolarprocess,growthandremodeling.
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71. Thank You
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