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GENERAL ETIOLOGICAL
FACTORS OFMALOCCLUSION
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INTRODUCTION:
Factors causing malocclusion can b broa!l"classi#i! into :
$ Gnral tiological #actors
$ Local tiological #actors
A gi%n cas o# malocclusion ma" it&r b
!u to singl or multi'l local or gnral
#actors or a combination o# local ( gnral
#actors An un!rstan!ing o# tiolog" is ssntial #or
'r%ntion) intrc'tion ( corrction o#
malocclusion
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CLASSIFICATION:
Nuro*
muscular
s"stm +on So#t tissu
,rnatal
trauma (
birt&
in-uris ,ostnatal
trauma
,rmatur
.traction o#
'rimar" tt& Natur o# #oo!
S"stmic !isass En!ocrin !isor!rs Local !isass
Naso'&ar"ngal
!isass ( !isturb!
rs'irator" #unction Gingi%al ( 'rio!ontal
!isass Tumours Caris
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GENERAL FACTORS LOCAL FACTORS
/0 1EREDITAR230 CONGENITAL40 EN5IRONMENTAL
,RENATAL 6TRAUMA) MATERNALDIET) GERMAN MEASLES) MATERNALMETA+OLISM7
,OSTNATAL 6+IRT1 IN8UR2)CELE+RAL ,ALS2) TM8 IN8UR27
90 ,REDIS,OSING META+OLIC CLIMATE (DISEASE
ENDOCRINE IM+ALANCE META+OLIC DISTUR+ANCES INFECTIOUS DISEASES
0 DIETAR2 ,RO+LEMS 6NUTRITIONALDEFICIENC27
;0 A+NORMAL ,RESSURE 1A+ITS (FUNCTIONAL A+ERRATIONS
A+NORMAL SUC
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WHITE & GARDINERS CLASSIFICATION
DENTAL BASE
ABNORMALITIES
PRE-ERUPTION
ABNORMALITIES
POST-ERUPTION
ABNORMALITIES
/0 ANTERO*,OSTERIORMALRELATIONS1I,
30 5ERTICALMALRELATIONS1I,
40 LATERALMALRELATIONS1I,
90 DIS,RO,ORTION OFSIE +ET=EENTEET1 ( +ASAL+ONE
0 CONGENITALA+NORMALITIES
/0 A+NORMALITIES IN,OSITION OFDE5ELO,INGTOOT1 GERM
30 MISSING TEET140 SU,ERNUMERAR2
TEET1 ( TEET1A+NORMAL IN FORM
90 ,ROLONGEDRETENTION OFDECIDUOUS TEET1
0 A+NORMAL LA+IALFRENUMATTAC1MENT
;0 TRAUMATIC IN8UR2
/0 MUSCULAR ACTI5E MUSCLE
FORCE REST ,OSITION
OFMUSCULATURE
SUCTRACTION OF,ERMANENT TEET1
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DENTITION: Folloing c&aractristics ar in#lunc! b" &r!it"*
S1A,E ( SIE OF TOOT1
$ Macro!ontia
$ Micro!ontia
$Abnormalitis o# toot& s&a') g: 'g latral
$ ,atints it& cto!rmal !"s'lasia .&ibit conical s&a'!
incisors ( s%ral congnitall" missing tt&
NUM+ER OF TEET1
$ Su'rnumrar" tt&
$ Congnitall" missing
ARC1 DIMENSION
$Arc& lngt& ( i!t&
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CRO=DING ( S,ACING
$Arc& lngt&*toot& matrial !iscr'anc"
$ Rsult o# !is&armonious in&ritanc o# toot& si #rom
on 'arnt ( -a lngt& #rom ot&r 'arnt
S1EDDING ,ATTERN OF DECIDUOUS TEET1 (
SEUENCE OF ERU,TION OF ,ERMANENT TEET1
INTER*ARC1 5ARIATION
$ D%iation in t& trans%rs sagittal ( %rtical 'lan
rlations&i' o# u''r ( lor -a
O5ER8ET
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S
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NEUROMUSCULAR S2STEM
D#ormitis in si) 'osition) tonicit")
contractilit" ( nuromuscular coor!ination
'attrn o# #acial) oral ( tongu
musculatur
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SOFT TISSUE
E.am's:
$ Si)s&a' ( attac&mnt o# labial #rnum
$An"loglossia
$ Microstomia
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CONGENITAL DEFECTS D%lo'mntal mal#ormation at tim o# birt&
Ma" b caus! b" local or gnral #actors
Gnral Congnital Factors
$Abnormal stat o# mot&r !uring 'rgnanc"
$ Malnutrition
$ En!ocrino'at&is$ In#ctious !isass) g: congnital s"'&ilis) matrnal rublla
in#ction
$ Mtabolic ( nutritional !isturbancs
$ Intrautrin 'rssur
$Acci!nts !uring 'rgnanc" ( c&il! birt&
$Acci!ntal trauma to #tus b" .trnal #orcs) g: #orc' !li%r"
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Local Congnital Factors:
$Abnormalitis o# -a !%lo'mnt !u to
abnormal intrautrin 'osition
$ C"st o# #ac ( 'alat
$ Macroglossia
$ Microglossia$ Cli!ocranial !"stosis
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CLEFT LI, ( ,ALATE
Most commonl" sn congnital !#ormit"
Ma" &a% 'ro#oun! in#lunc on
cranio#acial !%lo'mnt ( ma" caus
malocclusion o# %ar"ing !grs o#
s%rit"
Cl#t 'alat ma" rtar! normal
!%lo'mnt o# ma.illa t&rb" causing
Class III malocclusion
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Features: Congnitall" missing tt& in t& cl#t rgion
Su'rnumrar" tt& Micro!ontia ( 'g s&a'! tt& s' u''r latral
incisor
Cro!ing o# tt& in ara o# cl#t Insu##icint !%lo'mnt o# 'rma.illa
Crossbit !u to narro ma.illar" arc&
Rotation o# tt&
Abnormal o%r-t ( o%rbit
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CLEIDOCRANIAL D2SOSTOSIS:
,artial or com'lt absnc o# cla%icl on
on or bot& si!s
Features:
$ Ma.illar" rtrusion
$ ,ossibl man!ibular 'rotrusion
$ Rtain! !ci!uous tt&
$ Rtar!! ru'tion o# 'rmannt tt&
$ Numrous im'act! su'rnumrar" tt&
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MATERNAL RU+ELLA INFECTION DURING
,REGNANC2:
Rublla in#ction in a 'rgnant mot&r can
caus !ntal !#cts in t& c&il! suc& as:
$ Rtar!! ru'tion o# tt&
$ 1"'o'lasia o# tt&
$ E.tnsi% caris
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CONGENITAL S2,1ILIS:
Features:
$ 1utc&insonHs incisors
$ Mulbrr" molars
$ Ma.illar" !#icinc"
$Antrior crossbit
$ E.tnsi% !ntal caris
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EN5IRONMENTAL CAUSES:
,rnatal or 'ostnatal
Prenatal environmental factors:
$Abnormal #tal 'ostur !uring gstation
$ Matrnal #ibroi!s
$Amniotic lsions
$ Matrnal !it ( mtabolism
$ Inta o# crtain !rugs !uring 'rgnanc") g:
t&ali!omi! inta can caus congnital
!#ormitis li cl#ts
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Postnatal environmental factors:
$ Traumatic in-uris to t& con!"l ( TM8 ara !uring
birt& can caus man!ibular grot& rtar!ation$An"losis o# t& TM8 ma" la! to &"'o'lastic
man!ibl ( mar! #acial as"mmtr" in cas o#
unilatral an"losis
$ ,rsnc o# scar tissu) caus! b" cl#t 'alatsurgr" ma" caus malocclusion as t&" can rstrict
grot& o# ma.illa
$ Milau bracs us! #or t& tratmnt o# scoliosis
!ri% su''ort #rom t& man!ibl) t&us can causrtar!ation o# man!ibular grot&
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,REDIS,OSING META+OLIC CLIMATE
( DISEASES:
En!ocrinal imbalanc ma" 'r!is'os to
!%lo'mnt o# malocclusion
T&"roi! &ormons 'la" an im'ortant rol
in normal !%lo'mnt o# bons ( tt&
,arat&ormon &as an acti% rol in
calcium mtabolism ( is !irctl" in%ol%!
in !%lo'mnt o# tt& ( bons
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Hypothyroidism:$ Rtar!ation in rat o# calcium !'osition in bon (
tt&
$ Dla"! toot& bu! #ormation ( ru'tion$ ,rolong! rtntion o# 'rimar" ( !la"! ru'tion o#
'rmannt tt&
$ Irrgularitis in toot& arrangmnt ( cro!ing o# tt&
ma" occurHyperthyroidism:
$Associat! it& incras! mtabolic rat ( incras!
rat o# maturation
$ ,rmatur ru'tion o# 'rimar" ( 'rmannt !ntition
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Hypoparathyroidism:
$ O#tn associat! it& !la"! ru'tion o# tt&) altr!
mor'&olog" ( &"'o'lasia o# tt&
Hyperparathyroidism:
$ Causs an incras in bloo! calcium l%ls b" rsor'tion
o# bon0 Trabcular 'attrn o# -a ma" gt !isru't! !u
to !minralisation o# bon
$ In c&il!rn) toot& !%lo'mnt ma" bcom mobil !uto loss o# cortical bon ( rsor'tion o# al%olar bon
$ Osto'orosis in suc& 'arts contrain!icats ort&o!ontic
toot& mo%mnt
$Acut #bril !isas !uring !%lo'mnt "ars ma"caus !isturbancs in toot& ru'tion ( s&!!ing 'attrn)
'r!is'osing to malocclusion
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DIETAR2 ,RO+LEMS
NUTRITIONAL DEFICIENCIES: Nutritional !#icincis ma" caus malocclusion
'rimaril" b" u'stting t& !ntal !%lo'mntal
tim tabl ( rsulting in 'rmatur loss)
'rolong! rtntion ( abnormal ru'ti% 'at& Disturbancs) suc& as ricts) scur%" ( bribri
can 'ro!uc s%r malocclusion
Nutritional !#icincis !uring 'rgnanc" &a%
bn associat! it& crtain mal#ormations in
t& c&il!) inclu!ing crtnism ( cl#t li' ( 'alat
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A+NORMAL ,RESSURE 1A+ITS (
FUNCTIONAL A+ERRATIONS:
Abnormal 'rssur &abits li !igit
sucing) tongu t&rusting) li' biting (
#unctional abrration suc& as mout&
brat&ing ma" caus a %arit" o#malocclusions
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,OSTURE:
Man!ibular rtrusion &as bn obsr%! in
som stoo' s&oul!r! c&il!rn it& &a!
&ung so t&at t& c&in rsts on t& c&st ( in
som c&il!rn &o rst t&ir c&in on t&&an! to su''ort t&ir &a!
1o%r) 'oor 'ostur as a caus o#
malocclusion is not 'ro%! N%rt&lss) it ma" accntuat an .isting
malocclusion
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ACCIDENT ( TRAUMA:
Traumatic in-uris to t& !nto#acial rgion ar Juit
common !uring arl" "ars o# li# &n c&il! larns to
cral) al ( %n &il 'la"ing
Suc& traumatic .'rincs o#tn go unnotic! ( ma"
rsult in #olloing 'roblms 'r!is'osing to
malocclusion:
$ Non %ital !ci!uous tt& t&at !o not rsorb
$ D#lction o# 'rmannt toot& grms
$Abnormal ru'tion 'at& o# 'rmannt succssors0
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T1AN< 2OUKKK