Classification and Etiology

7/31/2019 Classification and Etiology

1/74

1

ETIOLOGY OF MALOCCLUSION

&HABITS

Dr. Biswaroop Mohanty


2/74

Malocclusion is a developmental condition.

Any perversion of normal occlusion of teeth.

Malposed teeth are but the symptoms of

errors of growth in the osseous framework of

the facial structures.

2


3/74

Grabers Classification General factors

1. Hereditary.2. Congenital defects.

- Cleft palate.- Torticollis.

- Cleidocranial dysostosis- Cerebral palsy.- Syphilis.

3. Environmentala. Prenatal

- Trauma.- Maternal diet.- Maternal metabolism.- German measles.

3

b. Postnatal

- Birth injuries.

- Cerebral palsy.

- TMJ injuries.


4/74

4. Predisposing metabolic climate & disease

a. Endocrine imbalance.b. Metabolic disturbances.c. Infectious diseases (poliomyelitis).

5. Dietary problems.

6. Abnormal pressure habits & functional

aberrations.a. Abnormal suckling.b. Thumb & finger sucking.

4


5/74

c. Tongue thrusting & sucking.d. Lip/nail biting.e. Abnormal swallowing.

f. Speech defects.g. Respiratory abnormalities.h. Tonsils/adenoids.i. Psychogenic aberrations clenching/bruxism.

7. Posture.

8. Trauma.

5


6/74

Local factors

1. Anomalies of number.

a. Missing.

b. Supernumerary.

2. Abnormalities in tooth size.

3. Abnormalities in tooth shape.

4. Abnormal labial frenum, mucosal barriers.5. Premature loss.

6. Prolonged retention.

7. Delayed eruption of permanent teeth.

8. Abnormal eruptive path.9. Ankylosis.

10. Dental caries.

11. Improper dental restorations.

6


7/74

Hereditary / Genetic factors in

malocclusion Strong influence of heritance of facial

features- obvious at a glance.

The Hapsburg jaw- prognathic mandible.

7


8/74

Heredity also plays an important role in the foll.conditions-

1. Congenital deformities.2. Facial asymmetries.

3. Macro/micrognathia.

4. Macro/microdontia.

5. Oligodontia & anodontia.6. Tooth shape variations.

7. Cleft-lip/palate.

8. Frenum diastemas.

9. Deep overbites.10. Crowding & rotation of teeth.

11. Mandibular retrusion.

12. Mandibular prognathism.8


9/74

Congenital defects

CLEFT LIP & CLEFT PALATE.

9

1in every 800 live births.

Both dental & skeletal

components affected.

More common in maxilla-damage to profile due tomaxillary deficiency.


10/74

Lack of muscular co-ordination.

Intracranial

lesion,Birth-injury. Lack of motor control-

abnormal musclefunction.

Upset musclebalance-malocclusion.

10

CEREBRAL PALSY


11/74

TORTICOLLIS (Wry Neck):

Foreshortening of sternocleidomastoid.

Profound changes in bony morphology ofcranium & face.

11


12/7412

CLEIDOCRANIAL

DYSOSTOSIS:

Hereditaryimportant cause ofmalocclusion.

Unilateral/bilateral absence ofclavicles.

Delayed closure of cranialsutures.

Maxillary retrusion.

Mandibular protrusion.

Retarded eruption of permanentteeth

Retained deciduous teeth.

Multiple impacted

supernumerary teeth.


13/74

CRANIOFACIAL DYSOSTOSIS (Crouzons disease):

13

Genetic disease.

Cranial & facial deformities.Hypoplasia of maxilla.

Mandibular prognathism.

High-arched palates & clefts.


14/74

Hereditary.

Hypoplasia of mandible. Microstomia.

High-arched palate with

/without cleft.

Abnormal positions ofteeth.

14

MANDIBULOFACIAL DYSOSTOSIS

(Treacher-Collins Syndrome)


15/74

PIERRE ROBIN SYNDROME:

15

May/may not be genetic.

Characterised by- cleft palate,micrognathia,glossoptosis.

Primary defect in the mandible.

Respiratory difficulty due to epiglotticobstruction.


16/74

Etiology unknown-hormonal imbalance orchromosomal abnormalities.

Effects on the dentition-increase in crownsize(50%),root size,increased rate ofdevelopment.

Maxilla and mandible enlarged. 16

FACIAL HEMIHYPERTROPHY


17/74

CONGENITAL SYPHILIS.

17

Abnormally shaped & malposed teeth.Screw-driver incisors, mulberry molars.

Short maxilla, high-arched palate.


18/74


19/74

Environment PRE-NATAL

Intrauterine moulding:

Pressure against rapidly growing areas

leads to distortion

Arm pressed against the face-maxillary

deficiency

Head flexed against the chest-

mandibular deficiency.

Decreased amniotic fluid-small

mandible-cleft palate results due to

upward displacement of tongue.

19


20/74

Teratogens

Chemicals and drugs consumed at lowdoses,causes malformation of dentofacial

structures.

20


21/74

German measles(Rubella)

When occurs in the I trimester of pregnancy

causes a number of developmental defects. Cleft lip/palate,enamel hypoplasia,delayed

eruption of teeth.

21


22/74

POST-NATAL

Birth injuriesTrauma tomandible

Most mandibular

deformities-due tocongenitalanomalies-butthought to be due

to birth trauma. Forceps delivery

TMJ damage.

22


23/74

Fractures of the jaw

Mandible more common than the maxilla.

Condylar neck is vulnerable. 75% of these fractures normal growthoccurs.

Asymmetric growth due to injury to the

soft tissue matrix scarring restricts thegrowth.

23


24/74

PREDISPOSING METABOLIC CLIMATE

AND DISEASE.

Endocrine imbalance.

Hypopituitarism:

Dwarf

Delayed eruption of permanent teeth anddelayed shedding of primary teeth.

Crowding due to smaller arch size. Mandibular growth more affected thanmaxilla.

24


25/74

Gigantism-large teeth and jaws.

Acromegaly-occurs after growth and ossificationis complete. Lips thick,tongue enlarged,shows scalloping. Accelerated condylar growth-large mandible.

Teeth tipped buccally due to large tongue. 25

Hyperpituitarism:


26/74

Hypothyroidism:

26

Delayed eruption.

Abnormal resorption pattern.

Retained deciduous teeth.

Malposed teeth-deflected from eruption path.

Gingival disturbances.

Hyperthyroidism:

Early shedding and eruption

Atrophy of alveolar bone.


27/74

Nutritional Deficiency.

Disturbances in the developmental timetable.

Rickets,scurvy and beri-beri can produce severemalocclusions.

Premature loss of teeth /Prolonged retention. Abnormal eruptive path. Poor tissue health

Poor absorption-hormonal /enzymaticdeficiency.

Decreased fluoride intake-loss of teeth due tocaries-malocclusion.

27


28/74

Abnormal Habits

All habits are learned patterns of musclecontraction of a very complex nature.

Habits such as normal lip action and

mastication-stimulants for normal growth,Undesirable habits malocclusion.

28


29/74

Duration not the only determinant butfrequency & intensity affect the end result.

The trident of habit factors.

29


30/74

Deleterious habitual patterns of musclesbehavior produce:

1. Perverted osseous growth.2. Tooth malpositions.

3. Disturbed breathing.

4. Difficulty in speech.5. Upset balance of facial musculature.

6. Psychological problems.

30


31/74

Thumb/Finger sucking

One of the most important factors in producing

and maintaining malocclusion. Begins at birth and outgrown by 3-4 years.

Finger sucking from birth to 4 years:

Suckling mechanism most important exchangewith the outside world.

Through suckling child obtains- nutrients,feelings of euphoria, sense of security and

feeling of warmth. 31


32/74

Digit Sucking & Malocclusion.

Large percentage of children practicing digit sucking but little

correlation with malocclusion. Sucking habits in primary dentition little or no long term effects.

Habits persist beyond the time that the permanent teeth erupt -malocclusion occurs.

Characterized by flared & spaced maxillary incisors, linguallypositioned lower incisors, anterior open bite, narrow upper arch.

32


33/74

Tongue Thrusting

Often associated with thumb sucking.

Tongue thrust is forward placement of thetongue between the anterior teeth & against thelower lip during swallowing- Schneider (1982).

Normal swallow the teeth are in occlusion, lipslightly closed, the tongue held against the palatebehind the anterior teeth.

33

T P t & T


34/74

Tongue Posture & Tongue

Size

TONGUE POSTURE:

Tongue thrust swallowing short duration to have impacton tooth position.

If posture of tongue isforward resting for longduration effects toothposition.

34


35/74

TONGUE SIZE:

Macroglossia can lead to proclination of

anteriors & anterior openbite.

35

Aglossia/Microglossia can lead to crowdingand lingual inclination of teeth.


36/74

Skeletal openbite

Steep mandibular plane. Increased anterior facial height.

Tongue thrusting results due to lack of

anterior seal.

36


37/74

Respiratory Pattern

Respiratory needs Primary determinants ofthe jaw & tongue.

Breathing through the mouth altersequilibrium of the jaws & teeth.

Lowering of the mandible & tongue &extension of the head is seen.

37


38/74

Effects of mouth-breathing:

Increase in facial height.

Supraeruption of posterior teeth.

Rotation of mandible downwards &backwards.

Open bite anteriorly.

Increase in overjet.

Pressures from stretched cheeks narrowmaxillary arch.-Posterior crossbite .

&class II malocclusion.

38


39/74

Causes leading to mouth breathing:

1. Chronic respiratory obstruction.

2. Mechanical obstruction.

3. Size of the nostril.4. Pharyngeal tonsils or adenoids (adenoid facies).

Greater effort required to breath through thenose tortuous nasal passages.

Partial blockage of the nose leads to resistanceof airflow person shifts to mouth breathing.

39


40/74

Lip-Sucking & Lip-Biting

May be seen on its own or associated with thumb

sucking. Mandibular lip mostly involved.

Results in labioversion of maxillary teeth.

Open bite & linguoversion of mandibular incisors.

40


41/74

Nail-Biting

Seen in high strung & nervous children.

Symptom of social & psychologicmaladjustment.

Often mentioned to cause malposition butrarely does.

41


42/74

Clenching & Bruxism

Very obscure in relation to malocclusion.

Is rhythmic contraction of the masticatory

muscle side to side grinding & gnashing ofteeth during sleep.

Wearing down of teeth occurs damages theocclusion.

42


43/74

Can occur due to nervous tension or when

there is existing malocclusion deep biteor single high contact due to restorationsor malpositions.

Vicious circle one leading to another.

43


44/74

Posture

Frequently suggested that poor posture canlead to malocclusion.

Stooping with chin on the chest- mandibular

retrusion.Child resting head on hand or sleeping on

arm or fist- possible development ofmalocclusion.

May accentuate existing malocclusion.

44

Appliances Leading to


45/74

Appliances Leading to

Malocclusion Milwaukee Brace

Given in thetreatment ofscoliosis.

Holds the head inextended position.

Constant pressure

on the mandible causesmalocclusion.

45


46/74

Accident or Trauma

Undiscovered traumatic experiences-significant in malocclusion.

Eruptive abnormalities.

Abnormal resorption.

Loss of vitality.

46

Local factors


47/74

Local factors

Anomalies in number of teeth.

Supernumerary & missing teeth.

Additions or deletions of teeth causes adisturbance within the arch & the opposing

arch.Supernumerary teeth.

Closely resembles the teeth / group of teethto which it belongs molars, premolars or

anteriors. .

47


48/74

Etiology

Splitting of the permanent tooth bud. Hereditary tendency.

Commonly found in the maxilla.

Commonest mesiodens between maxillarycentral incisors.

Can be conical in shape, singly or in pairs,inverted or fused.

48


49/74

Maxillary 4th molar second most common.Causes malocclusion deflection or non-eruptio

of the permanent teeth.

Cause malposition of adjacent teeth.Careful removal of these teeth required,

49


50/74

Complications :

Delayed eruption- drifting of teeth, arch lengthdecrease

Displaced, rotated teeth 82% displaced labially Diastema

Dilacerations/ malformation of teeth

Crowding

Cyst formation dentigerous cyst Eruption into nasal cavity

Resorption of adjacent roots

50


51/74

Management :

Early surgical removal

1. Reduces risk of mid line deviation

2. Reduces cross bite decreases mal occlusion Delayed extraction

1. If doesnt interfere with eruption of adjacentteeth

2. Observation recommended3. Can lead to displacement of permanent tooth

buds

4. Child tolerates extractions better at an older age

51


52/74

More frequent than supernumerary.

Frequent in permanent than deciduous.

False/induced anodontia result of extractionof teeth.

True partial anodontia (hypodontia /oligodontia) congenitally missing one ormore teeth (hereditary).

52

2. Missing teeth


53/74

Commonly missingteeth.

Maxillary &mandibular thirdmolars.

Maxillary lateral

incisor. Mandibular 2nd

premolar.

Maxillary incisors. Maxillary 2nd

premolars.

53


54/74

Malocclusions due to absence of teeth.

Spacing. Drifting of teeth.

Abnormal eruption permanent canines

erupt mesially if maxillary lateral incisors aremissing.

If permanent tooth is lost one must decide

its space has to be maintained or can be usedfor orthodontic therapy.

54


55/74

Anomalies of tooth size

55

Discrepancies in size makes normal alignment& occlusion impossible.

Size largely determined by heredity.

1. Microdontia-

Teeth smaller than normal.

Generalized microdontia leads to spacing.Seen in pituitary dwarfism.

Single tooth microdontia more common.

Commonly affected -


56/74

Commonly affected

Maxillary lateral incisors.

3rd molars.

Mandibular 2

nd

premolar.2. Macrodontia-

Teeth larger than normal.

Generalized macrodontia rare condition pituitarygigantism.

Single tooth macrodontia unknown etiology causescrowding.

56


57/74

Anomalies of tooth shape:

Peg lateral - most common spacing in themaxillary anterior segment.

Maxillary central incisors exaggerated

cingulum / heavy marginal ridges preventnormal overbite & overjet.

Mandibular premolars with extralingual cuspincreases the mesiodistal dimension.

57


58/74

Conditions which affectthe tooth shape.

1. Gemination divisionof a single tooth germ.

2. Fusion union of twonormally seperated

teeth. Spacing & crowding

cause due to the aboveanomalies difficult toachieve propermidlines, esthetics &occlusion.

58


59/74

Concrescence

fusion of roots bycementum.

Dilaceration sharpbend or curve in theroot.

59

Taurodontism

bulky crownswith short roots.

Abnormal Labial Frenum


60/74

Abnormal Labial Frenum

Cause of spacing between maxillary central incisors. Midline diastema may also be caused by-

1. Abnormal habits.

2. Tooth size discrepancies.

3. Congenitally missing teeth.4. Mesiodens.

5. Midline cysts.

6. Ugly Duckling Stage.

60

P t L f D id


61/74

Premature Loss of Deciduous

Teeth

Deciduous teeth- best spacemaintainers.

Premature loss- childs own

dental development / timetable. Unscheduled loss of 1 or more

dental units imbalance indental timetable.

61


62/74

Loss of primary incisors:

Seldom requires spacemaintenance.

If lost before 4yrs.- regularradiographic exam.

62

Loss of primary cuspids: Premature loss of dec.

maxillary canines- spacing ofpermanent incisors,labioversion of canines.

Mandibular dec. canine loss-lingual tipping of 4mandibular permanentincisors.

Loss of first primary molars:


63/74

Loss of first primary molars:

Will cause mesial

movement of second dec.molar & first permanentmolar.

In mandible- 2nd premolar

blocked out.

63

Loss of second primary molars:

Early loss- mesial drifting of 1st

permanent molar & distalmovement of canine.

2nd premolar blocked out.

L f i l


64/74

Loss of 2 or more primary molars:

Mesial drifting of 1st

permanent molars &distal drifting of anteriors.

Cross-bite may occur as mandibular positionis changed to achieve occlusion.

64

P l d R t ti & Ab l


65/74

Prolonged Retention & Abnormal

Resorption of Deciduous Teeth.

Mechanicalobstruction- leadsto deflective path

of eruption orimpaction of thepermanent tooth.

Prolonged

retention-endocrine historycheck.

65


66/74

66

Radiographic exam. required when there is unusualdelay in eruption.

Familial patterns of eruption timings must beassessed.


67/74

Delayed Eruption of

Permanent Teeth

Causes:

1. Supernumerary tooth.

2. Mucosal barrier.

3. Premature loss of primary tooth-bony crypt forms in the line oferuption.

Delayed eruption- drifting ofadjacent teeth & space closure-blocking out or impaction ofpermanent tooth.

67

Abnormal Eruptive Path


68/74

p

Deflection in path oferuption due to-

1. Lack of space due toarch-length deficiency.

2. Supernumerary tooth.3. Presence of a root

fragment from primarytooth.4. Blow to the face-

deflection of primarytooth/ tooth bud.

5. Mechanical interferenceby orthodontictreatment.

6. Cysts.

68


69/74

In ectopic eruption erupting perm. toothmay resorb root of adjacent tooth-manifestation of arch-length deficiency.

69

Ankylosis


70/74

y

Maybe due to injury- disruptionof periodontal ligament.

Formation of bony bridge-replacement resorption.

Commonly seen in mandibularprimary second molar-Submerged Tooth.

Causes-

1. Impaction/ abnormal path oferuption of perm. successor.

2. Growth of alveolar bone is

affected.

70


71/74

Dental Caries

Loss of crown substance (several proximalcaries) severe arch-length loss.

Supra-eruption, abnormal axial inclination,tipping of the tooth occurs.

71

Improper Dental Restorations


72/74

Improper Dental Restorations

1. Undermined restorations- supra-eruption ofteeth.

2. High restorations- premature contacts-mandibular shifts.

3. Under-contoured proximal contacts- spaceloss.

4. Over-contoured adjacent teeth pushed

away-occlusal contacts disrupted- functionalprematurities.

5. Severe disruption- cross-bite.

72


73/74

Gingival & Periodontal

Disease. Causes malocclusion by-1. PDL breakdown- pathological

migration.

2. Tooth loss.

73

Tumours

Push teeth away as theyenlarge.

Severe malocclusion whenfound in articulatory region.


74/74

Conclusion

What we think we know today shatters the

errors and blunders of yesterday and istomorrow discarded as worthless. So we gofrom larger mistakes to smaller mistakes- solong as we do not lose courage. This is true of

all therapy; no method is final.

- Frederick Jensen

Documents

Classification and Etiology