Classification of Etiologic Factors in Orthodontics

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 CONTENTSCONTENTS::
 INTRODUCTIONINTRODUCTION
 SYSTEM OF CLASSIFICATION OF ETIOLOGIC FACTORSSYSTEM OF CLASSIFICATION OF ETIOLOGIC FACTORS
 CLASSIFICATIONSCLASSIFICATIONS
 ORTHODONTIC EQUATIONORTHODONTIC EQUATION
 PRIMARY ETIOLOGIC SITESPRIMARY ETIOLOGIC SITES
 GENERAL FACTORS:GENERAL FACTORS:
i) HEREDITYi) HEREDITY
ii) CONGENITAL DEFECTSii) CONGENITAL DEFECTS
iii) ENVIROMENTiii) ENVIROMENT
iv) PREDISPOSING METABOLIC CLIMATE &iv) PREDISPOSING METABOLIC CLIMATE &
SYSTEMIC DISEASESSYSTEMIC DISEASES
v) NUTRITIONAL DEFICIENCYv) NUTRITIONAL DEFICIENCY
vi) ABNORMAL PRESSURE HABITSvi) ABNORMAL PRESSURE HABITS
vii) TRAUMAvii) TRAUMA

Introduction:Introduction:
 Etiology is the science of investigation, study, &Etiology is the science of investigation, study, &
demonstration of causes of diseasedemonstration of causes of disease
 Etiology in orthodontics is the study of the actual causesEtiology in orthodontics is the study of the actual causes
of dentofacial abnormalitiesof dentofacial abnormalities
 Etiology is a greek word.Etiology is a greek word.
 Etiology:Etiology: atiaatia means cause &means cause & logouslogous means studymeans study
 Etiologic factors may express themselves indirectlyEtiologic factors may express themselves indirectly
through general constitutional changes which affect thethrough general constitutional changes which affect the
occlusion of the teeth, or directly in the dento-maxillo-occlusion of the teeth, or directly in the dento-maxillo-
facial area.facial area.

SYSTEM OF CLASSIFICATION OFSYSTEM OF CLASSIFICATION OF
ETIOLOGIC FACTORS:ETIOLOGIC FACTORS:
 It refers to i) inherited or congenital causesIt refers to i) inherited or congenital causes
ii) acquired causesii) acquired causes
Inherited & congenital causes:Inherited & congenital causes:
 These are the characteristics inherited from parentsThese are the characteristics inherited from parents
 Problem of tooth number and sizeProblem of tooth number and size
 Congenital deformitiesCongenital deformities
 Condition affecting mother during pregnancyCondition affecting mother during pregnancy
 Fetal environmentFetal environment

 Acquired causes:Acquired causes:
 Premature loss and prolonged retention of decidousPremature loss and prolonged retention of decidous
teethteeth
 HabitsHabits
 Abnormal functionAbnormal function
 DietDiet
 TraumaTrauma
 Metabolic and endocrine disturbancesMetabolic and endocrine disturbances

 Another approach is to divide the causative factorsAnother approach is to divide the causative factors
into:into:
i)i) Indirect or predisposing causesIndirect or predisposing causes
ii)ii) Direct or determining causesDirect or determining causes
 Indirect or predisposing causesIndirect or predisposing causes::
 Congenital defectsCongenital defects
 Prenatal abnormalitiesPrenatal abnormalities
 Acute and chronic infectious & deficiency diseasesAcute and chronic infectious & deficiency diseases
 Metabolic disturbancesMetabolic disturbances
 Endocrine imbalance & unknownEndocrine imbalance & unknown

 Direct or determing causes:Direct or determing causes:
 Missing teethMissing teeth
 Supernumerary teethSupernumerary teeth
 Transposed teethTransposed teeth
 Malformed teethMalformed teeth
 Abnormal labial frenumAbnormal labial frenum
 Intrauterine pressureIntrauterine pressure
 PosturePosture
 Abnormal muscular habitsAbnormal muscular habits
 Malfunctioning musclesMalfunctioning muscles
 Premature shedding of decidous teethPremature shedding of decidous teeth
 Tardy erruption of permanent teethTardy erruption of permanent teeth
 Prolonged retention of decidous teethProlonged retention of decidous teeth
 Loss of permanent teeth & improper restorationLoss of permanent teeth & improper restoration

Classifications:Classifications:
Moyer lists seven “causes and clinical entities”.Moyer lists seven “causes and clinical entities”.11
1 Heredity.1 Heredity.
2 Developmental defects of unknown origin.2 Developmental defects of unknown origin.
3 Trauma: prenatal trauma & birth injuries3 Trauma: prenatal trauma & birth injuries
postnatal traumapostnatal trauma
4 Physical agents: premature extraction of primary4 Physical agents: premature extraction of primary
teeth, nature of foodteeth, nature of food
5 Habits.5 Habits.
6 Disease.6 Disease.
7 Malnutrition.7 Malnutrition.

 Pre and Post natal factors of MalocclusionPre and Post natal factors of Malocclusion11
..
Shows the interdependence of etiological factors inShows the interdependence of etiological factors in
Malocclusion .Modification of SALZMANN’S(1966)Malocclusion .Modification of SALZMANN’S(1966)
diagrammatic representation of the etiologic factors indiagrammatic representation of the etiologic factors in
Malocclusion embodying pre and post natal factors:Malocclusion embodying pre and post natal factors:
 PRENATALPRENATAL POSTNATALPOSTNATAL
GENETIC DEVELOPMENTALGENETIC DEVELOPMENTAL
DIFFERENTIATIVE FUNCTIONALDIFFERENTIATIVE FUNCTIONAL
CONGENITAL ENVIRONMENTALCONGENITAL ENVIRONMENTAL

 Prenatal:Prenatal:
1.1. Genetic:Genetic: transmitted by genes dentofacial anomalies,transmitted by genes dentofacial anomalies,
may or may not be evidence at birthmay or may not be evidence at birth
2.2. Differentiative:Differentiative: inborn, engrafted on the body in theinborn, engrafted on the body in the
prefunctional embryonic developmental stageprefunctional embryonic developmental stage
3.3. Congenital:Congenital: hereditary or acquired but existing athereditary or acquired but existing at
birthbirth
 Postnatal:Postnatal:
1.1. Developmental:Developmental: general & localgeneral & local
 General: birth injuries, abnormalities of relative rate ofGeneral: birth injuries, abnormalities of relative rate of
growth in different body organsgrowth in different body organs
 Endocrine disturbances, nutritional disturbancesEndocrine disturbances, nutritional disturbances
 RadiationRadiation
 Local: abnormalities in dentofacial complexLocal: abnormalities in dentofacial complex

 Micrognathia, macrognathia abnormal labial frenum,Micrognathia, macrognathia abnormal labial frenum,
facial hemiatrophy.facial hemiatrophy.
 Anomalies of tooth development.Anomalies of tooth development.
 Functional:Functional:
1.1. General: muscular hyper-hypotonicityGeneral: muscular hyper-hypotonicity
 Postural defectsPostural defects
 Respiratory disturbances, mouth breathingRespiratory disturbances, mouth breathing
2.2. Local: loss of force caused by failure of proximalLocal: loss of force caused by failure of proximal
contact of teethcontact of teeth
 Tempromandibular articulation disturbancesTempromandibular articulation disturbances
 Masticatory & facial muscular hypo or hyperactivityMasticatory & facial muscular hypo or hyperactivity

 Environmental or acquired:Environmental or acquired:
1.1. General: disease can affect the dentofacial tissues orGeneral: disease can affect the dentofacial tissues or
by affecting other parts of the body indirectly disturbby affecting other parts of the body indirectly disturb
the teeth & jawsthe teeth & jaws
2.2. Nutritional disturbancesNutritional disturbances
3.3. Metabolic disturbancesMetabolic disturbances
4.4. TraumaTrauma
5.5. RadiationRadiation
 Local: disturbed force of occlusionLocal: disturbed force of occlusion
2.2. Early loss of decidous & permanent teethEarly loss of decidous & permanent teeth
3.3. Periodontal diseasesPeriodontal diseases
4.4. Pressure habitsPressure habits
5.5. Traumatic injuries, fractures of jawsTraumatic injuries, fractures of jaws

GRABER’s CLASSIFICATION;GRABER’s CLASSIFICATION;
 GENERAL FACTORS:GENERAL FACTORS:
i) Heredityi) Heredity
ii) Congenitalii) Congenital
iii) Environment: a) pre nataliii) Environment: a) pre natal
b) post natalb) post natal
iv) Predisposing metabolic disease and climate:iv) Predisposing metabolic disease and climate:
a) endocrine imbalancea) endocrine imbalance
b) metabolic disturbancesb) metabolic disturbances
c) infectious diseasesc) infectious diseases
v) Dietary problemsv) Dietary problems
vi) Abnormal pressure habits:vi) Abnormal pressure habits:
a) abnormal suckinga) abnormal sucking
b) thumb and finger suckingb) thumb and finger sucking

c) tongue thrustc) tongue thrust
d) lip and nail bitingd) lip and nail biting
e) abnormal swallowing habitse) abnormal swallowing habits
f) speech defectsf) speech defects
g) respiratory abnormalitiesg) respiratory abnormalities
h) tonsils and adenoidsh) tonsils and adenoids
i) psychogenic tics and bruxismi) psychogenic tics and bruxism
vii) Posturevii) Posture
viii) Traumaviii) Trauma
 LOCAL FACTORS:LOCAL FACTORS:
i) Anomalies of tooth number (supernumerary teeth,i) Anomalies of tooth number (supernumerary teeth,
missing teeth, absence or loss due to accidents)missing teeth, absence or loss due to accidents)
ii) Anomalies of tooth sizeii) Anomalies of tooth size

iiif) Anomalies of tooth shapeiiif) Anomalies of tooth shape
iv) Abnormal labial frenumiv) Abnormal labial frenum
v) Premature loss of decidous teethv) Premature loss of decidous teeth
vi) Prolonged retention of decidous teethvi) Prolonged retention of decidous teeth
vii) Delayed erruption of permanent teethvii) Delayed erruption of permanent teeth
viii) Abnormal erruptive pathviii) Abnormal erruptive path
ix) Ankylosisix) Ankylosis
x) Dental cariesx) Dental caries
xi) Improper dental restorationxi) Improper dental restoration

White and gardiner’s classification (1954):White and gardiner’s classification (1954):
 Dental base abnormalities:Dental base abnormalities:
1.1. Anterio posterior malrelationshipAnterio posterior malrelationship
2.2. Vertical malrelationshipVertical malrelationship
3.3. Lateral malrelationshipLateral malrelationship
4.4. Disproportion of size between teeth and basal boneDisproportion of size between teeth and basal bone
5.5. Congenital abnormalitiesCongenital abnormalities
 Pre erruption abnormalitiesPre erruption abnormalities ::
1.1. Abnormalities in position of tooth germAbnormalities in position of tooth germ
2.2. Missing teethMissing teeth
3.3. Supernumerary teethSupernumerary teeth
4.4. Prolonged retention of decidous teethProlonged retention of decidous teeth

5.5. Large labial frenumLarge labial frenum
6.6. Traumatic injuryTraumatic injury
 Post erruption abnormalities:Post erruption abnormalities:
1.1. Muscular: a) active muscle forceMuscular: a) active muscle force
b) rest position of musculatureb) rest position of musculature
c) sucking habitsc) sucking habits
d) abnormalities in the path of closured) abnormalities in the path of closure
2.2. Premature loss of decidous teethPremature loss of decidous teeth
3.3. Extraction of permanent teethExtraction of permanent teeth

Orthodontic equation:Orthodontic equation:
(Dockrell R; 1952)(Dockrell R; 1952)
 It gives a brief expression of development of dentofacial abnormalities (malocclusion).It gives a brief expression of development of dentofacial abnormalities (malocclusion).
 CAUSE acts as TIMES on TISSUE produce RESULTSCAUSE acts as TIMES on TISSUE produce RESULTS
some predisposing prenatal or primarily may be the followingsome predisposing prenatal or primarily may be the following
some exciting post natal secondarily or combination ofsome exciting post natal secondarily or combination of
thesethese
1 heredity 1 continuous or 1 neuromuscular tissue 1 malfunction1 heredity 1 continuous or 1 neuromuscular tissue 1 malfunction
2 developmental intermittent 2 teeth 2 malocclusion2 developmental intermittent 2 teeth 2 malocclusion
causes of unknown 2 may act at 3 bone & cartilage 3 osseous dysplasiacauses of unknown 2 may act at 3 bone & cartilage 3 osseous dysplasia
origin different age 4 soft tissueorigin different age 4 soft tissue
3 trauma levels3 trauma levels
4 physical agents4 physical agents
5 habits5 habits
6 disease6 disease
7 malnutrition7 malnutrition

Primary etiologic sites:Primary etiologic sites:
 The neuromuscular system:The neuromuscular system:
 It plays a primary role in the etiology of dentofacialIt plays a primary role in the etiology of dentofacial
deformity by the effects of reflex contractions on thedeformity by the effects of reflex contractions on the
bony skeleton and dentition.bony skeleton and dentition.
 Some neuromuscular contraction patterns are adaptiveSome neuromuscular contraction patterns are adaptive
to skeletal imbalances or dental malpositionsto skeletal imbalances or dental malpositions
 Treatment of malocclusion must involve conditioning ofTreatment of malocclusion must involve conditioning of
reflexes to bring about more favourable functionalreflexes to bring about more favourable functional
environment for – growing craniofacial skeleton andenvironment for – growing craniofacial skeleton and
developing dentitiondeveloping dentition

 Bone:Bone:
 Maxilla and mandible serve as bases for the dentalMaxilla and mandible serve as bases for the dental
archesarches
 Aberrations in their morphology or growth may alterAberrations in their morphology or growth may alter
occlusal relationship and functioningocclusal relationship and functioning
 Orthodontic treatment for skeletal disharmony mustOrthodontic treatment for skeletal disharmony must
either- alter the growing craniofacial skeletoneither- alter the growing craniofacial skeleton
-camouflage it by moving teeth to mask its-camouflage it by moving teeth to mask its
disharmonydisharmony
 Teeth:Teeth:
 Primary site in the etiology of dentofacial deformityPrimary site in the etiology of dentofacial deformity
 Gross variations in the size, shape, no. or position ofGross variations in the size, shape, no. or position of
teeth all can produce malocclusionteeth all can produce malocclusion

 Malposition of teeth can induce malfunction and thus canMalposition of teeth can induce malfunction and thus can
alter the growth of the bonesalter the growth of the bones
 Soft parts:Soft parts:
 the role of the soft tissue is not clearly discernible as thatthe role of the soft tissue is not clearly discernible as that
of the other 3 sitesof the other 3 sites
 Malocclusion can result from periodontal disease andMalocclusion can result from periodontal disease and
loss of the attachment apparatus & variety of soft tissueloss of the attachment apparatus & variety of soft tissue
lesions including TMJ structurelesions including TMJ structure
 Time:Time:
 In developing malocclusion it has 2 componentsIn developing malocclusion it has 2 components
 Period during which the cause operatesPeriod during which the cause operates
 The age at which it is seenThe age at which it is seen

 Length of time that a certain cause may be operative isLength of time that a certain cause may be operative is
not always continual and may cease and recur in annot always continual and may cease and recur in an
intermittent fashion.intermittent fashion.
 From etiologic point of view the most useful division ofFrom etiologic point of view the most useful division of
the age component is - cause active prenatallythe age component is - cause active prenatally
- effects noted after birth.- effects noted after birth.

General factors:General factors:
 General factors are those that effect the body as a wholeGeneral factors are those that effect the body as a whole
and has profound effect on the greater part of theand has profound effect on the greater part of the
dentofacial structuresdentofacial structures
 Heredity:Heredity:
 There are certain racial & familial characteristics thatThere are certain racial & familial characteristics that
tend to recurtend to recur
 Offspring is a product of parents of dissimilar heredityOffspring is a product of parents of dissimilar heredity
 this means the possibilities of a recapitulation of athis means the possibilities of a recapitulation of a
heredity trait from either parents or a combination fromheredity trait from either parents or a combination from
both parents to produce a modified characteristicboth parents to produce a modified characteristic

 GALTON’S LAW(1940)GALTON’S LAW(1940) : Galton formulated the: Galton formulated the
statement that any organism of bisexual parentage,statement that any organism of bisexual parentage,
derives one half of its inherited qualities from its parentsderives one half of its inherited qualities from its parents
( one quarter form each parents) one quarter form its( one quarter form each parents) one quarter form its
grand parents one eight form its great grand parents andgrand parents one eight form its great grand parents and
so on.so on.
 These successive functions whose numerators are 1 andThese successive functions whose numerators are 1 and
whose denominations are the successive powers of 2whose denominations are the successive powers of 2
added together equal or the total inheritance of theadded together equal or the total inheritance of the
organisms.organisms.
1/2,1/4,1/8,1/16,1/32,1/64…… =11/2,1/4,1/8,1/16,1/32,1/64…… =1
 The consensus of opinion seems to be that Galton’s lawThe consensus of opinion seems to be that Galton’s law
only expressed a part of what is known of the regularonly expressed a part of what is known of the regular
courses of inheritance.courses of inheritance.

 According to KARKHAU’S (1957), heredity plays anAccording to KARKHAU’S (1957), heredity plays an
important influence on the following:important influence on the following:
1.1. size and shape of the teeth.size and shape of the teeth.
2.2. Time of eruption and change of dentitionTime of eruption and change of dentition
3.3. Abnormalities of individual teeth and groups of teethAbnormalities of individual teeth and groups of teeth
4.4. Size and shape of the maxilla and mandible.Size and shape of the maxilla and mandible.
 According to Lundstrom (1955)According to Lundstrom (1955)
patients who are "genetically better" than their status atpatients who are "genetically better" than their status at
the beginning of the treatment have a better prognosisthe beginning of the treatment have a better prognosis
than patients of the opposite type, in whom Naturethan patients of the opposite type, in whom Nature
already has used the available margin of modification,already has used the available margin of modification,
 The Hapsburg Jaw , the prognathic mandible in theThe Hapsburg Jaw , the prognathic mandible in the
European royal familyEuropean royal family

 Heredity racial influence:Heredity racial influence:
 Dental characteristic also show racial influenceDental characteristic also show racial influence
 In homogenous racial groupings the incidence ofIn homogenous racial groupings the incidence of
malocclusion seems relatively lowmalocclusion seems relatively low
 Where there has been mixture of racial strains theWhere there has been mixture of racial strains the
incidence of jaw size discrepancies & occlusalincidence of jaw size discrepancies & occlusal
disharmonies is significantly greaterdisharmonies is significantly greater
 Anthropologists shows us that the jaws seem to beAnthropologists shows us that the jaws seem to be
smaller, there is a greater frequency of impaction of 3smaller, there is a greater frequency of impaction of 3rdrd
molar teeth, greater the influence of congenital absencemolar teeth, greater the influence of congenital absence
of certain teeth & retrognathic tendencyof certain teeth & retrognathic tendency

 Hereditary facial type:Hereditary facial type:
 Facial type of the offspring is heavily influenced byFacial type of the offspring is heavily influenced by
heredityheredity
 Facial typing is 3- dimensionalFacial typing is 3- dimensional
 Different ethnic groups & mix of ethnic groups haveDifferent ethnic groups & mix of ethnic groups have
differently shaped headsdifferently shaped heads
i)i) Brachycephalic- broad round headsBrachycephalic- broad round heads
ii)ii) Dolicocephalic- long narrow headsDolicocephalic- long narrow heads
iii)iii) Mesocephalic- in between the above twoMesocephalic- in between the above two
 In arbitrary division there are many gradationsIn arbitrary division there are many gradations
 Broad face- broad cranial and facial, broad dentalBroad face- broad cranial and facial, broad dental
archesarches
 Long narrow face- harmonious bony structure, narrowLong narrow face- harmonious bony structure, narrow
dental archesdental arches

 Hereditary influence on the growth andHereditary influence on the growth and
developmental pattern:developmental pattern:
 Morphogenetic pattern has strong hereditary componentMorphogenetic pattern has strong hereditary component
 Eg:- onset of puberty varies with the different races &Eg:- onset of puberty varies with the different races &
with geographic distributionwith geographic distribution
 With its attendant growth & developmental pattern itsWith its attendant growth & developmental pattern its
confined to a narrow age range & begins earlier in girlsconfined to a narrow age range & begins earlier in girls
than in boysthan in boys
 Hereditary and specific dentofacial &Hereditary and specific dentofacial &
morphologic characteristics:morphologic characteristics:
 Lundstorm made an intensive analysis of theseLundstorm made an intensive analysis of these
characteristics in twins and concluded that heredity couldcharacteristics in twins and concluded that heredity could
be considered significant in determining the followingbe considered significant in determining the following
characteristics-characteristics-

 Tooth sizeTooth size
 Width & length of the archWidth & length of the arch
 Height of the palateHeight of the palate
 Crowding and spacing of teethCrowding and spacing of teeth
 Degree of sagittal overbiteDegree of sagittal overbite
 It also influences conditions like-It also influences conditions like-
 Congenital deformitiesCongenital deformities
 Facial asymmetriesFacial asymmetries
 Macrognathia & micrognathiaMacrognathia & micrognathia
 Oligodontia & anodontiaOligodontia & anodontia
 Tooth shape variations, crowding & rotations of teethTooth shape variations, crowding & rotations of teeth
 Cleft palate and harelipCleft palate and harelip
 Frenum diastemasFrenum diastemas
 Mandibular retrognathism & prognathismMandibular retrognathism & prognathism

Congenital defects:Congenital defects:
 Cleft lip & palate:Cleft lip & palate:
 Congenital or developmental defects are usuallyCongenital or developmental defects are usually
assumed to have a strong genetic relationshipassumed to have a strong genetic relationship
 1/31/3rdrd
to ½ of cleft palate children have a familial history ofto ½ of cleft palate children have a familial history of
this deformitythis deformity
 1 child in every 700 live births is afflicted1 child in every 700 live births is afflicted
 Cleft lip & palate provide nature’s laboratory & anCleft lip & palate provide nature’s laboratory & an
opportunity for us to observe aberrations in growth &opportunity for us to observe aberrations in growth &
development- inherent & environmentally induceddevelopment- inherent & environmentally induced
 With all forms of surgery maxillofacial techniques haveWith all forms of surgery maxillofacial techniques have
undergone fads and fashionundergone fads and fashion

 Traumatic uranoplasty procedures close clefts byTraumatic uranoplasty procedures close clefts by
molding the seperated parts togethermolding the seperated parts together
 Classification of cleft:Classification of cleft:
 Class I; soft palate with possible notching of hard palateClass I; soft palate with possible notching of hard palate
 Class II; soft & hard palate, but no alveolar ridgeClass II; soft & hard palate, but no alveolar ridge
 Class III; complete unilateral lip-jaw-palate cleft, right orClass III; complete unilateral lip-jaw-palate cleft, right or
leftleft
 Class IV; complete bilateral lip-jaw-palate cleftClass IV; complete bilateral lip-jaw-palate cleft
 Cases may also be categorized with alveolar ridge cleftCases may also be categorized with alveolar ridge cleft
only, lip cleft only, & a true midline cleft.only, lip cleft only, & a true midline cleft.

 Restoration of normal function with proper lip closureRestoration of normal function with proper lip closure
produces dramatic molding effects on the premaxillaproduces dramatic molding effects on the premaxilla
 In unilateral cleft teeth on the side of the cleft are usuallyIn unilateral cleft teeth on the side of the cleft are usually
in lingual crossbite with the opposing lower teethin lingual crossbite with the opposing lower teeth
 Many times premaxilla is displaced anteriorly or becauseMany times premaxilla is displaced anteriorly or because
of tightly repaired lip, premaxilla is forced linguallyof tightly repaired lip, premaxilla is forced lingually
 Maxillary incisors are frequently badly malposed withMaxillary incisors are frequently badly malposed with
bizzare axial inclinationbizzare axial inclination

 Is a paralysis or lack of muscular coordination attributedIs a paralysis or lack of muscular coordination attributed
to an intracranial lesionto an intracranial lesion
 Most commonly considered to be the result of birth injuryMost commonly considered to be the result of birth injury
 Effects of this neuromuscular disorder may be seen inEffects of this neuromuscular disorder may be seen in
the integrity of the occlusionthe integrity of the occlusion
 Varying degree of abnormal muscle function may occurVarying degree of abnormal muscle function may occur
in mastication, degluttition, respiration and speech.in mastication, degluttition, respiration and speech.
 The uncontrolled or aberrant activities upset the muscleThe uncontrolled or aberrant activities upset the muscle
balance that is necessary for a normal occlusionbalance that is necessary for a normal occlusion
Cerebral palsy:Cerebral palsy:

Torticollis:Torticollis:
 The far reaching effects ofThe far reaching effects of
abnormal muscle forces areabnormal muscle forces are
visible in torticollis or “wryvisible in torticollis or “wry
neck”neck”
 The foreshortening of theThe foreshortening of the
sternocleidomastoid musclesternocleidomastoid muscle
can cause profound chanfgescan cause profound chanfges
in the bony morphology of thein the bony morphology of the
cranium & facecranium & face
 Bizzare facial asymmetriesBizzare facial asymmetries
with incorrectable dentalwith incorrectable dental
malocclusion may be created ifmalocclusion may be created if
this problem is not treatedthis problem is not treated
fairlyfairly

Cleidocranial dysostosis:Cleidocranial dysostosis:
 Unilateral or bilateral, partial or complete absence of theUnilateral or bilateral, partial or complete absence of the
clavicle in conjunction with delayed cranial sutureclavicle in conjunction with delayed cranial suture
closure, maxillary retrusion and possible mandibularclosure, maxillary retrusion and possible mandibular
protrusionprotrusion
 Retarded erruption of permanent teeth & overretainedRetarded erruption of permanent teeth & overretained
decidous teethdecidous teeth
 Roots of permanent teeth are sometimes short & thin,Roots of permanent teeth are sometimes short & thin,
supernumerary teeth are commonsupernumerary teeth are common
 High narrow arched palate & actual cleft palate appearsHigh narrow arched palate & actual cleft palate appears
to be common, absence of cellular cementum onto be common, absence of cellular cementum on
permanent teethpermanent teeth

Congenital syphilis:Congenital syphilis:
 Acquired or congenitalAcquired or congenital
 Abnormally shaped teeth & malposed teeth areAbnormally shaped teeth & malposed teeth are
characteristic disease phenomenacharacteristic disease phenomena
 Person with congenital syphilis manifest great variety ofPerson with congenital syphilis manifest great variety of
lesions including frontal bossae, short maxilla, highlesions including frontal bossae, short maxilla, high
palatal arch, saddle nose, irregular thickening ofpalatal arch, saddle nose, irregular thickening of
sternoclavicular portion of the clavicle, protruberance ofsternoclavicular portion of the clavicle, protruberance of
mandiblemandible
 Hutchinson’s teeth- hypoplasia of maxillary permanentHutchinson’s teeth- hypoplasia of maxillary permanent
incisor & molar teeth, usually barrel shaped orincisor & molar teeth, usually barrel shaped or
screwdriver shaped with the greatest circumference ofscrewdriver shaped with the greatest circumference of
the tooth located more gingivally than usual.the tooth located more gingivally than usual.

Pierre robin syndrome:Pierre robin syndrome:
 Consists of cleft palate,Consists of cleft palate,
micrognathia and glossoptosismicrognathia and glossoptosis
 Primary defect lies in arrestedPrimary defect lies in arrested
development & ensuingdevelopment & ensuing
hypoplasia of mandible- birdhypoplasia of mandible- bird
faceface
 Prevents the normal descendPrevents the normal descend
of the tongue between theof the tongue between the
palatal shelves, resulting inpalatal shelves, resulting in
cleft palatecleft palate
 Jaw malformation andJaw malformation and
respiratory difficultyrespiratory difficulty
 Failure of support of tongueFailure of support of tongue
musculature occurs becausemusculature occurs because
of micrognathia, allowing theof micrognathia, allowing the
tongue to fall down andtongue to fall down and
backward partially obstructingbackward partially obstructing
epiglottisepiglottis www.indiandentalacademy.comwww.indiandentalacademy.com

Treacher collins syndrome:Treacher collins syndrome:
 Also known as mandibulofacialAlso known as mandibulofacial
dysostoisdysostois
 Hypoplasia of facial bones,Hypoplasia of facial bones,
especially of the malar bonesespecially of the malar bones
& mandible& mandible
 Macrostomia, high palate &Macrostomia, high palate &
abnormal position &abnormal position &
malocclusion of teethmalocclusion of teeth
 Facial clefts and skeletalFacial clefts and skeletal
deformitiesdeformities
 Bird like or fish likeBird like or fish like
appearanceappearance

Craniofacial dysostosis:Craniofacial dysostosis:
 Crouzon’s diseaseCrouzon’s disease
 The facial malformationThe facial malformation
consists of hypoplasia ofconsists of hypoplasia of
maxilla with mandibularmaxilla with mandibular
prognathismprognathism
 High arched palate, cleft lip &High arched palate, cleft lip &
palate is rare, but lateralpalate is rare, but lateral
palatal swellings producepalatal swellings produce
midline maxillary pseudocleftmidline maxillary pseudocleft
 Facial angle is exaggeratedFacial angle is exaggerated
and the patients nose isand the patients nose is
described as resembling todescribed as resembling to
parrot’s beakparrot’s beak

Maternal rubella infection:Maternal rubella infection:
 During pregnancy as a possible cause of widespreadDuring pregnancy as a possible cause of widespread
congenital malformations in the childcongenital malformations in the child
 The most commom dental defects are; retardation in theThe most commom dental defects are; retardation in the
teeth erruptionteeth erruption
 Dental hypoplasiaDental hypoplasia
 Malocclusion & cariesMalocclusion & caries
 Retarded physical development & microcephalyRetarded physical development & microcephaly

Radiation:Radiation:
 The 1The 1stst
trimester of pregnancy is the most critical stage intrimester of pregnancy is the most critical stage in
the formation of the human fetus, when malformationsthe formation of the human fetus, when malformations
due to radiation can occur.due to radiation can occur.
 The fetus may be damaged even by small doses ofThe fetus may be damaged even by small doses of
radiation from radiographyradiation from radiography
 Malformations which occur are cleft palate, mongolism,Malformations which occur are cleft palate, mongolism,
microcephaly & hydrocephaly & deformed limbs.microcephaly & hydrocephaly & deformed limbs.

Environment:Environment:
 Prenatal influencePrenatal influence
 Post natal influencePost natal influence
 Pre-natal influencePre-natal influence : role of prenatal influence in: role of prenatal influence in
malocclusion is probably very smallmalocclusion is probably very small
 But there are certain factors, in the presence of whichBut there are certain factors, in the presence of which
can result in abnormal growth of the orofacial regioncan result in abnormal growth of the orofacial region
there by predisposing to malocclusion.there by predisposing to malocclusion.
 They are uterine posture, fibroids of the mother, amnioticThey are uterine posture, fibroids of the mother, amniotic
lesionslesions

 Others are maternal diet & metabolism, drug inducedOthers are maternal diet & metabolism, drug induced
deformities, possible injury or trauma & german measles.deformities, possible injury or trauma & german measles.
 Abnormal fetal posture & maternal fibroids leads toAbnormal fetal posture & maternal fibroids leads to
cranial or facial asymmetries, which disappears in latercranial or facial asymmetries, which disappears in later
lifelife
 Post-natal influence:Post-natal influence:
 Birth is a tremendous shock to a new born, but theBirth is a tremendous shock to a new born, but the
cranial bones slide more than facial & dental archescranial bones slide more than facial & dental arches
 The plasticity of the structures is such that any injuryThe plasticity of the structures is such that any injury
would be temporary except in rare instanceswould be temporary except in rare instances

 Injury at birth with high forceps delivery at times leads toInjury at birth with high forceps delivery at times leads to
permanent damage to TMJ jointpermanent damage to TMJ joint
 Depending on the damage “spastics” may have bizzare,Depending on the damage “spastics” may have bizzare,
atypical dental malocclusions as the normal muscularatypical dental malocclusions as the normal muscular
balance is disturbedbalance is disturbed
 Accidents produce undue pressure on the developingAccidents produce undue pressure on the developing
dentition, eg; condylar fractures, extensive scar tissuedentition, eg; condylar fractures, extensive scar tissue
because of burnsbecause of burns
 Plaster neck cast- due to fractured cervical vertebraePlaster neck cast- due to fractured cervical vertebrae
leading to strong elevating forces on mandible, forcingleading to strong elevating forces on mandible, forcing
the maxillary incisors labially & mandibular incisors fitthe maxillary incisors labially & mandibular incisors fit
deep into impressions in the palatal mucosa.deep into impressions in the palatal mucosa.
 Milwaukee brace or similar braces in the treatment ofMilwaukee brace or similar braces in the treatment of
scoliosis.scoliosis.

TERATOGENS AFFECTINGTERATOGENS AFFECTING
DENTOFACIAL DEVELOPMENT:DENTOFACIAL DEVELOPMENT:
 Aspirin – cleft lip and palateAspirin – cleft lip and palate
 Aminopterin – anecephalyAminopterin – anecephaly
 Dilantin – cleft lip and palateDilantin – cleft lip and palate
 Ethyl alcohol – central and mid face deficiency, alcoholEthyl alcohol – central and mid face deficiency, alcohol
fetal syndrome.fetal syndrome.
 5 – mercapturine – cleft palate5 – mercapturine – cleft palate
 Valium – cleft lip and palateValium – cleft lip and palate
 Diazepam – floppy baby syndrome.Diazepam – floppy baby syndrome.
 Anesthetics –abortion and multiple defect.Anesthetics –abortion and multiple defect.
(Chloroform, Halothane)(Chloroform, Halothane)

 Thalidomide – Phocomelia, multiple defects and growth.Thalidomide – Phocomelia, multiple defects and growth.
 Corticosteroids – cleft palate and lipCorticosteroids – cleft palate and lip
 Tetracycline –Discolored and deformed teeth,Tetracycline –Discolored and deformed teeth,
retarded bone growth.retarded bone growth.
 Phenytoin - Hypoplastic phalanges, cleft lip and palatePhenytoin - Hypoplastic phalanges, cleft lip and palate
 Warfarin – Nose, eye and hand defects, growthWarfarin – Nose, eye and hand defects, growth
retardation.retardation.
 Oral contraceptives – cardiac, ear and CNS defects.Oral contraceptives – cardiac, ear and CNS defects.
 Oral hypoglycaemics – neonatal hypoglycemia.Oral hypoglycaemics – neonatal hypoglycemia.
 Antithyroids – goiter with hypothyroidism.Antithyroids – goiter with hypothyroidism.
 ACE inhibitors – intrauterine growth retardation.ACE inhibitors – intrauterine growth retardation.

 Antihypertensive – anuria and multiple defects.Antihypertensive – anuria and multiple defects.
 Antiemetics – cleft palate and cardiovascular defects.Antiemetics – cleft palate and cardiovascular defects.
 Cigarette smoking – cleft lip and palate.Cigarette smoking – cleft lip and palate.
 Cytomegalovirus – microcephaly, hydrocephaly.Cytomegalovirus – microcephaly, hydrocephaly.
 X-radiation – microcephaly.X-radiation – microcephaly.
 Vitamin D excess – premature suture closure.Vitamin D excess – premature suture closure.

Equilibrium theory and dental malocclusion:Equilibrium theory and dental malocclusion:
 It follows that if any object is subjected to a set of forcesIt follows that if any object is subjected to a set of forces
but remains in the same position those forces must be inbut remains in the same position those forces must be in
balance or equilibriumbalance or equilibrium
 The dentition in equilibrium, subjected to variety of forcesThe dentition in equilibrium, subjected to variety of forces
but do not move to a new location under usualbut do not move to a new location under usual
circumstancescircumstances
 it also apply to the skeleton including the facial skeletonit also apply to the skeleton including the facial skeleton
 Equilibrium effects on dentition: the contributors ofEquilibrium effects on dentition: the contributors of
equilibrium that governs the tooth position are-equilibrium that governs the tooth position are-
 Fluid filled PDL acts as shock absorberFluid filled PDL acts as shock absorber

 pressure from cheek lips & tonguepressure from cheek lips & tongue
 pressure from external sources: habits, orthodonticpressure from external sources: habits, orthodontic
appliancesappliances
 Equilibrium effects on the jaw size & shape:Equilibrium effects on the jaw size & shape:
 Muscular processes- the growth of the muscle helpsMuscular processes- the growth of the muscle helps
determining the position of the attachment & so muscledetermining the position of the attachment & so muscle
growth can produce a change in shape of the jawgrowth can produce a change in shape of the jaw
particularly at the coronoid process & the angle of theparticularly at the coronoid process & the angle of the
mandiblemandible
 The equilibrium influences would affect the vertical asThe equilibrium influences would affect the vertical as
well as horizontal position of the teeth & could have awell as horizontal position of the teeth & could have a
profound effect on tooth erruptionprofound effect on tooth erruption

Systemic diseases and endocrinalSystemic diseases and endocrinal
disorders:disorders:
 Acute febrile disease may slow down the pace of growthAcute febrile disease may slow down the pace of growth
and developmentand development
 Disease with paralytic effect such as poliomyelitis areDisease with paralytic effect such as poliomyelitis are
capable of producing bizzare malocclusioncapable of producing bizzare malocclusion
 Disease with muscle malfunction such as muscularDisease with muscle malfunction such as muscular
dystrophy & cerebral palsy have characteristic effect ondystrophy & cerebral palsy have characteristic effect on
the dental archthe dental arch
 Thyroid problems afflict an estimated 2 or 3% of ourThyroid problems afflict an estimated 2 or 3% of our
populationpopulation

Role of thyroid:Role of thyroid:
 Plays an essential role in the differentiation growth,Plays an essential role in the differentiation growth,
maturation, water balance, electrolyte balance, proteinmaturation, water balance, electrolyte balance, protein
storage, carbohydrate & lipid metabolism & otherstorage, carbohydrate & lipid metabolism & other
physiologic functionphysiologic function
 Thyroxin stimulates the erruptive movement & tooth sizeThyroxin stimulates the erruptive movement & tooth size
but has little influence on alveolar growthbut has little influence on alveolar growth
 HYPOTHYROIDISM:HYPOTHYROIDISM:
 Retardation in the rate of calcium deposition in bonesRetardation in the rate of calcium deposition in bones
and teethand teeth
 Leads to mental defects, retarded somatic growth,Leads to mental defects, retarded somatic growth,
generalized edema & other changes depending on thegeneralized edema & other changes depending on the
severity of deficiencyseverity of deficiency

 Base of the skull isBase of the skull is
shortened, retraction ofshortened, retraction of
the bridge of nose withthe bridge of nose with
flaringflaring
 Mandible isMandible is
underdeveloped, maxillaunderdeveloped, maxilla
is overdevelopedis overdeveloped
 Tongue is enlarged &Tongue is enlarged &
may protrudemay protrude
continuously leading tocontinuously leading to
malocclusionmalocclusion
 Erruption rate ofErruption rate of
permanent teeth ispermanent teeth is
delayed & decidous teethdelayed & decidous teeth
are over retainedare over retained

 HYPERTHYROIDISM:HYPERTHYROIDISM:
 Increased basal metabolic rateIncreased basal metabolic rate
 Alveolar atrophy occurs in advanced casesAlveolar atrophy occurs in advanced cases
 Shedding of decidous teeth occurs earlier than theShedding of decidous teeth occurs earlier than the
normal & erruption of permanent teeth is acceleratednormal & erruption of permanent teeth is accelerated
 Retardation of skeletal growthRetardation of skeletal growth
 Early closure of epiphyseal growth centre- resulting inEarly closure of epiphyseal growth centre- resulting in
dwarfismdwarfism

Role of parathyroid glands:Role of parathyroid glands:
 Parathyroid gland regulates the level of blood calciumParathyroid gland regulates the level of blood calcium
and phosphorous metabolism. They play an importantand phosphorous metabolism. They play an important
role in the calcification of the teeth and bone.role in the calcification of the teeth and bone.
 HYPERPARATHYROIDISM:HYPERPARATHYROIDISM:
 Disease is 3 times common in women than in menDisease is 3 times common in women than in men
 Loss of calcium & phosphorus results in generalizedLoss of calcium & phosphorus results in generalized
osteoporosis with abortive attempts at bone repair &osteoporosis with abortive attempts at bone repair &
bone formationbone formation
 Pathologic fracture, bone pain & joint stiffnessPathologic fracture, bone pain & joint stiffness
 Teeth may become mobile due to bone resorptionTeeth may become mobile due to bone resorption

 HYPOPARATHYROIDISMHYPOPARATHYROIDISM
::
 Decrease excretion of calciumDecrease excretion of calcium
 Low concentration of serumLow concentration of serum
calcium and highcalcium and high
concentration of phosphorusconcentration of phosphorus
 Enamel hypoplasia frequentlyEnamel hypoplasia frequently
seenseen
 Skeletal growth is impairedSkeletal growth is impaired

Role of pitutary gland:Role of pitutary gland:
 It controls the entire spectrum of human growth &It controls the entire spectrum of human growth &
developmentdevelopment
 HYPOPITUTARISM:HYPOPITUTARISM:
 Deficiency may be congenital or due to destructiveDeficiency may be congenital or due to destructive
disease of the pitutarydisease of the pitutary
 Leads to pitutary dwarfismLeads to pitutary dwarfism
 Delayed erruption rate & shedding time of the teethDelayed erruption rate & shedding time of the teeth
 Clinical crown appears smaller than normalClinical crown appears smaller than normal
 Dental arches are small and cannot accommodate allDental arches are small and cannot accommodate all
teeth leading to malocclusionteeth leading to malocclusion

 Roots are shorter & supporting structures are retarded inRoots are shorter & supporting structures are retarded in
growthgrowth
 Osseous development of mandible is retardedOsseous development of mandible is retarded
 HYPERPITUTARISM:HYPERPITUTARISM:
 Gigantism is characterized by a general symmetric overGigantism is characterized by a general symmetric over
growth of the bodygrowth of the body
 Teeth are proportional to the size of the jaws & rest ofTeeth are proportional to the size of the jaws & rest of
the bodythe body
 Roots are longer than normalRoots are longer than normal
 Lips become thick & negroidLips become thick & negroid
 Enlarged tongue & shows indentations on the sides fromEnlarged tongue & shows indentations on the sides from
pressure against the teethpressure against the teeth
 Teeth are tipped to buccal or labial sideTeeth are tipped to buccal or labial side
 Accelerated condylar growth- large mandibleAccelerated condylar growth- large mandible

Nutritional deficiency:Nutritional deficiency:
 Malnutrition is more likely to effect the quality of tissuesMalnutrition is more likely to effect the quality of tissues
being formed & the rates of calcification than the size ofbeing formed & the rates of calcification than the size of
partsparts
 Nutritional related disorder such rickets, scurvy andNutritional related disorder such rickets, scurvy and
beriberi can produce severe malocclusion and mayberiberi can produce severe malocclusion and may
upset the dental developmentupset the dental development
 Combination of inorganic and organic elements areCombination of inorganic and organic elements are
active in many physiologic processes, constitute theactive in many physiologic processes, constitute the
basic structure of bone & teethbasic structure of bone & teeth

 CALCIUM PHOSPHORUS & MAGNESIUMCALCIUM PHOSPHORUS & MAGNESIUM ::
 Plays a major role in the formation of bones & teeth,Plays a major role in the formation of bones & teeth,
maintenance of skeletal structure & tooth structuremaintenance of skeletal structure & tooth structure
 Osteoporosis due to long term negative calcium balanceOsteoporosis due to long term negative calcium balance
 Magnesium deficient diet effects teeth & supportingMagnesium deficient diet effects teeth & supporting
structuresstructures
 Localized degeneration & subsequent formation ofLocalized degeneration & subsequent formation of
enamel hypoplasiaenamel hypoplasia

 DISTURBANCES IN PROTEIN METABOLISMDISTURBANCES IN PROTEIN METABOLISM ::
 overall growth & growth of the jaws is decreasedoverall growth & growth of the jaws is decreased
 Enamel is affected, incisors exhibit increase acidEnamel is affected, incisors exhibit increase acid
solubility & increase dental cariessolubility & increase dental caries
 Gingiva and PDL exhibit varying degree of degenerationGingiva and PDL exhibit varying degree of degeneration
 Teeth small & widely spaced, delayed erruption timeTeeth small & widely spaced, delayed erruption time
 DISTURBANCE IN LIPID METABOLISMDISTURBANCE IN LIPID METABOLISM ::
 Hand schuller christian diseaseHand schuller christian disease
 Sore mouth, gingivitisSore mouth, gingivitis
 Exfoliation of teeth & failure of healing of tooth socketsExfoliation of teeth & failure of healing of tooth sockets
following extractionfollowing extraction
 Loss of supporting alveolar boneLoss of supporting alveolar bone

 AVITAMINOSES:AVITAMINOSES:
 VITAMIN A:VITAMIN A:
 In vitamin A deficiency cells fail to differentiateIn vitamin A deficiency cells fail to differentiate
 Calcification is disturbed & enamel hypoplasia resultsCalcification is disturbed & enamel hypoplasia results
 Distortion of the shape of the toothDistortion of the shape of the tooth
 Erruption rate is retardedErruption rate is retarded
 VITAMIN D:VITAMIN D:
 Helps in bone growth and osseous structureHelps in bone growth and osseous structure
 Deficiency leads to ricketsDeficiency leads to rickets
 Developmental abnormalities of dentin & enamel &Developmental abnormalities of dentin & enamel &
misalignment of the teeth in the jawsmisalignment of the teeth in the jaws
 Erruption rate of the decidous & permanent teeth isErruption rate of the decidous & permanent teeth is
retardedretarded
 Poorly defined alveolar bone patternPoorly defined alveolar bone pattern

 VITAMIN C:VITAMIN C:
 Scurvy results fromScurvy results from
vitamin C deficiencyvitamin C deficiency
 deficiency in thedeficiency in the
development of bone,development of bone,
cartilage, dentin &cartilage, dentin &
connective tissueconnective tissue
 Deficiency occurs chieflyDeficiency occurs chiefly
in gingiva & periodontalin gingiva & periodontal
tissuestissues
 Loss of bone & looseningLoss of bone & loosening
of teeth seenof teeth seen

 VITAMIN BVITAMIN B::
 Deficiency of vitamin B1 (thiamin) leads to beri beri.Deficiency of vitamin B1 (thiamin) leads to beri beri.
 Characterized by multiple neuritis & often associatedCharacterized by multiple neuritis & often associated
with congestive cardiac failure.with congestive cardiac failure.
 Vitamin B2 (riboflavin) deficiency seen among childrenVitamin B2 (riboflavin) deficiency seen among children
who do not drink milk.who do not drink milk.
 Glossitis which begins with the soreness of the tip &Glossitis which begins with the soreness of the tip &
lateral margins of the tongue.lateral margins of the tongue.
 Retarded growth of the dentofacial tissues.Retarded growth of the dentofacial tissues.

Abnormal pressure habits:Abnormal pressure habits:
 Severity of malocclusion caused due to abnormal habitSeverity of malocclusion caused due to abnormal habit
depends upon the trident of factor ie. Frequency,depends upon the trident of factor ie. Frequency,
intensity, and duration. The role of abnormal pressureintensity, and duration. The role of abnormal pressure
habit in the cause of malocclusion will be dealt with thehabit in the cause of malocclusion will be dealt with the
followingfollowing
 All pressures fall into one of two classifications,All pressures fall into one of two classifications,
intentionalintentional
unintentionalunintentional

1.The intentional are the planned pressures1.The intentional are the planned pressures
A. Orthodontic treatment appliancesA. Orthodontic treatment appliances
B. Myofunctional therapyB. Myofunctional therapy
D. Giraffe-necks of the Padaung womenD. Giraffe-necks of the Padaung women
E. Chinese custom of foot bindingE. Chinese custom of foot binding

2.The unintentional or abnormal pressure habits are of2.The unintentional or abnormal pressure habits are of
three typesthree types
A. intrinsic or pressure habits within the mouth;A. intrinsic or pressure habits within the mouth;
 thumb-sucking,thumb-sucking,
 finger-sucking,finger-sucking,
 lip biting,lip biting,
 tongue thrustingtongue thrusting
 mouth breathingmouth breathing
 Lip-suckingLip-sucking
 Cheek-suckingCheek-sucking

B. extraneous or extrinsic, abnormal pressure habits on theB. extraneous or extrinsic, abnormal pressure habits on the
face;face;
1. chin propping,1. chin propping,
2. face leaning on forearm or hands,2. face leaning on forearm or hands,
3. abnormal pillowing positions3. abnormal pillowing positions
C. functional pressures.C. functional pressures.
1. Warping bones of the foot by wearing shoes that do1. Warping bones of the foot by wearing shoes that do
not fit properlynot fit properly
2. Narrowing the external auditory meatus on one side2. Narrowing the external auditory meatus on one side
by sleeping on that side of the head more than on theby sleeping on that side of the head more than on the
otherother
3. Malocclusion frequently developed in musicians from3. Malocclusion frequently developed in musicians from
pressure exerted on their teeth or facepressure exerted on their teeth or face
4. Flattening of an infant's head by laying infant4. Flattening of an infant's head by laying infant
habitually in one position for prolonged periods.habitually in one position for prolonged periods.

Thumb sucking:Thumb sucking:
 The severity of malocclusion caused by thumb suckingThe severity of malocclusion caused by thumb sucking
 Proclination of maxillary anterior teethProclination of maxillary anterior teeth
 Increase in overjet also due to lingual tipping of theIncrease in overjet also due to lingual tipping of the
mandibular incisorsmandibular incisors
 Anterior open bite due to restriction of incisor erruptionAnterior open bite due to restriction of incisor erruption
 Narrow maxillary arch with posterior crossbite due toNarrow maxillary arch with posterior crossbite due to
cheek muscle contractioncheek muscle contraction
 hypotonic upper lip & hyperactive mentalis activityhypotonic upper lip & hyperactive mentalis activity
 Characteristic pattern of class II malocclusionCharacteristic pattern of class II malocclusion

Tongue thrusting:Tongue thrusting:
 Proclination of anterior teethProclination of anterior teeth
 Increase in overbite & overjetIncrease in overbite & overjet
 Bimaxillary protrusionBimaxillary protrusion
 Posterior crossbitePosterior crossbite
 Posterior teeth errupts & gradually eliminate the interPosterior teeth errupts & gradually eliminate the inter
occlusal clearance.occlusal clearance.

Mouth breathing:Mouth breathing:
 Long and narrow face, facial height would increaseLong and narrow face, facial height would increase
 Narrow nose and nasal passageNarrow nose and nasal passage
 Short & flaccid upper lipShort & flaccid upper lip
 Contracted maxillary arch with possibility of posteriorContracted maxillary arch with possibility of posterior
cross bite & more upright incisorscross bite & more upright incisors
 Increased overjet as a result of flaring of incisors,Increased overjet as a result of flaring of incisors,
anterior open bite can occuranterior open bite can occur

Trauma:Trauma:
 Both prenatal trauma to the fetus and postnatal injuriesBoth prenatal trauma to the fetus and postnatal injuries
results in dentofacial deformityresults in dentofacial deformity
 prenatal trauma and birth injuryprenatal trauma and birth injury
 Postnatal – as a child learns to crawl and walk, face andPostnatal – as a child learns to crawl and walk, face and
dental process receive many blows that are not recordeddental process receive many blows that are not recorded
in history.in history.
 Such undiscovered traumatic experience many explainSuch undiscovered traumatic experience many explain
so called idiopathic eruptive abnormalities.so called idiopathic eruptive abnormalities.
 non vital deciduous teeth have abnormal resorptionnon vital deciduous teeth have abnormal resorption
patterns and may defect the permanent successors.patterns and may defect the permanent successors.
 If blow to the dental areas is strong, it may causesIf blow to the dental areas is strong, it may causes
fracture of jaws and tooth (as in automobile accidents).fracture of jaws and tooth (as in automobile accidents).
 Eg: When bilateral condylar fractures occur, anteriorEg: When bilateral condylar fractures occur, anterior
openbite and distal movement of the lower arch will beopenbite and distal movement of the lower arch will be
present, since the ramus shortens bilaterally.present, since the ramus shortens bilaterally.

Posture:Posture:
 Poor postured condition can cause malocclusionPoor postured condition can cause malocclusion
 A child with the head hung so that the chin rests on theA child with the head hung so that the chin rests on the
chest, has been accused of creating mandibularchest, has been accused of creating mandibular
retrusion.retrusion.
 Full fledged dental malocclusion may be caused by aFull fledged dental malocclusion may be caused by a
child resting his head for period of time each day orchild resting his head for period of time each day or
sleeping on his arm or fist.sleeping on his arm or fist.
 Also poor posture may accentuate on existingAlso poor posture may accentuate on existing
malocclusion.malocclusion.

Bibliography:Bibliography:
• T. M. Graber: Orthodontics Principles And Practice,3T. M. Graber: Orthodontics Principles And Practice,3rdrd
Ed, W. B. Saunders co. 1996,:255-395.Ed, W. B. Saunders co. 1996,:255-395.
• Nevillile, Damm, Allen, Bouqot: Oral And MaxillofacialNevillile, Damm, Allen, Bouqot: Oral And Maxillofacial
Pathology. 2Pathology. 2ndnd
Ed , Saunders 2005: 4,42-43.Ed , Saunders 2005: 4,42-43.
• Shafer, Hine, Levy: Textbook Of Oral Pathology, 5Shafer, Hine, Levy: Textbook Of Oral Pathology, 5thth
Ed,Elsevier.2005:453-454,52-55.Ed,Elsevier.2005:453-454,52-55.
• W R. Proffit, Contemporary Orthodontics; 4W R. Proffit, Contemporary Orthodontics; 4thth
Ed, Mosby,Ed, Mosby,
2007: 131-149.2007: 131-149.
• R.S.Satoskar, Bhandarkar, Ainapure:Pharmacology AndR.S.Satoskar, Bhandarkar, Ainapure:Pharmacology And
Pharmaco therapeutic, 17Pharmaco therapeutic, 17thth
Ed, Mumbai PopularEd, Mumbai Popular
Prakashan, 2001:1077.Prakashan, 2001:1077.

• T.C.White, J.H.Gardiner, Orthodontics for dentalT.C.White, J.H.Gardiner, Orthodontics for dental
students, 2students, 2ndnd
Ed, Macmillan Press 1983: 82Ed, Macmillan Press 1983: 82
• Robert E. Moyers- Handbook of orthodontics; 4Robert E. Moyers- Handbook of orthodontics; 4thth
edition;edition;
year book medical publishers; (147-157).year book medical publishers; (147-157).
• J.A. Salzman; practice of orthodontics; volume 1; (251-J.A. Salzman; practice of orthodontics; volume 1; (251-
270).270).
• Klein- Pressure habits, etiological factors in malocclusionKlein- Pressure habits, etiological factors in malocclusion
AJO-DO Volume 1952 Aug (569 - 587).AJO-DO Volume 1952 Aug (569 - 587).
• Lundström- The significance of genetic and non geneticLundström- The significance of genetic and non genetic
factors in the profile of the facial skeleton; AJO-DO,factors in the profile of the facial skeleton; AJO-DO,
Volume 1955 Dec (910 - 916).Volume 1955 Dec (910 - 916).
• Korkhaus- Disturbances in the development of the upperKorkhaus- Disturbances in the development of the upper
jaw and the middle face (Part I), Volume 1957 Nov (848 -jaw and the middle face (Part I), Volume 1957 Nov (848 -
868).868).

Classification of Etiologic Factors in Orthodontics

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Classification of Etiologic Factors in Orthodontics