• Classification of etiology of malocclusion
• Moyer’s classification
• Graber’s classification
Development of Dentition and Occlusion
Dent alveolar
Neuromuscular
Skeletal
Localization of possible etiology of malocclusion
is a difficult.
• Classification of etiology of malocclusionMoyer’s classification
Graber’s classification
Moyer’s classification
1.
Hereditary
a. Neuromuscular system
c. Teeth
b. Bone
d. Soft parts
2. Developmental defects of unknown origin
3. Trauma
a. Prenatal trauma and birth injuries.
4. Physical agents
5. Habits
6. Diseases
7. Malnutrition
B. post natal trauma
a. Premature extraction of primary teeth
a. Thumb sucking and finger sucking
c. Lip sucking and lip biting
e. Nail biting
b. nature of food
b. tongue thrusting
d. posture
f. other habits
a. Systemic disease
b. endocrine disease
c. Local diseases1. Nasopharyngeal diseases and disturbed respiratory functions
2. Gingival and Periodontal diseases
3. Tumors
4. Caries
Graber’s classification
1.
2.
Hereditary
Congenital
3.
Environmental
a. Pre-natal (trauma , maternal diet, german
measles, maternal metabolism etc…
b. Post- natal ( birth injury, cerebral palsy, T.M.J.
injury)
4.
Pre- disposing metabolic and climate diseases
a. Endocrine imbalances
b. Metabolic disturbances
c. Infectious diseases
5.
Dietary problems ( nutritional deficiency)
Graber’s classification
6. Abnormal pressure habits and functional aberrations
a. Abnormal sucking
b. Thumb and finger sucking
c. Tongue thrust and
d. Lip and nail biting
e. Abnormal swallowing habits ( improper deglutition)
f. Speech defects
g. Respiratory abnormalities ( mouth breathing etc….)
h. Tonsils and adenoids
i. psychogenic tics and bruxism
7. Posture
8. Trauma and accidents
Graber’s classification
Local Factors
1. Anomalies in number
Supernumerary teeth
Missing teeth ( congenital absence or loss due to accidents
, caries etc. )
2. Anomalies of tooth size
3. Anomalies of tooth shape
4. Abnormal labial frenum : mucosal barriers
5. Premature loss of deciduous teeth
6. Prolonged retention of deciduous teeth
7. Delayed eruption of permanent teeth
8. Abnormal eruptive path
9. Ankylosis
10. Dental caries
11. Improper dental restoration
Hereditary
• According to Lundstrom human traits that are
influenced by the genes includes• Tooth size
• Arch dimensions
• Crowding / spacing
• Abnormalities of tooth shape
• Abnormalities of tooth number
• Overjet
• Inter- arch variations
• Frenum – size , position and shape.
Congenital Defects
Malformations seen at the time of birth.
May caused by genetic, radiologic, chemical, endocrine, infectious and or
mechanical factors.
a.
b.
c.
d.
e.
f.
g.
h.
General congenital factors
abnormal state of mother during
pregnancy
Malnutrition
Endocrinopathies
Infectious diseases
Metabolic and nutritional
disturbances
Accidents during pregnancy and
childbirth
Intrauterine pressure
Accidental traumatization of the fetus
by external forces
Local congenital factors
a. Abnomalities of jaw
development due to intra
uterine position
b. Clefts of the face and
palate
c. Macro and microglossia
d. Cleidocranial dysostosis
Environmental
• Prenatal factors
 Maternal fibroids
 Amniotic lesions
 Maternal diet and
metabolism.
• Post natal factors
 Forcep delivery
 Cerebral palsy- loss of
muscle balance
 Condylar facture
 Scar tissue- burns or
cleft lip and palate
 Milwaukee braces ---- in
scoliosis--- mandibuar
retardation
Predisposing metabolic climate and diseases
Endocrine imbalance
Hypothyroidism--Delay in tooth bud formation
and eruption
Over retained deciduous teeth
Abnormal root resorption
Crowding
HyperthyroidismPremature exfoliation of
deciduous teeth
Disturbed root resorption of
deciduous teeth
Early eruption of permanent
teeth
Patient may have
osteoporosis which
contraindicates orthodontic
treatment.
Endocrine imbalance
•
•
•
•
Hypoparathyroidism
Delay in tooth eruption
Altered tooth
morphology
Delayed eruption of
deciduous and
permanent teeth
Hypoplastic eeth
Hyperparathyroidism
• Interruption of tooth
development
• Tooth mobile due to
loss of cortical bone and
resorption of alveolar
process.
 Metabolic disturbances
Acute febrile diseases
slow down pace of
growth and
development.
These conditions may
cause disturbance in
tooth eruption and
shedding hence
increases risk of
malocclusion.
 Accidents and trauma
Children---- when they
learn to crawl, walk or
during play.
Non vital teeth--- root
do not resorb.
Deflection of erupting
permanent teeth into
abnormal position.
Anomalies in tooth no.
Supernumerary teeth- mesiodens
Supplemental teeth
Missing teeth- congenitally missing--third molars,
maxillary lateral incisors,
mandibular second premolars,
mandibular incisors,
maxillary second premolars.
Anomalies of tooth size
Macrodontia & Microdontia
Anamolies of tooth shape
• Peg shaped maxillary lateral incisor
• Large cingulum on maxillary incisors
• Congenital syphilis- peg shaped lateral and
mulberry molars.
• Dilaceration
• Developmental defects- amelogenesis
imperfecta, hypoplasia of teeth, fusion,
gemination.
Abnormal labial frenum- diastema
Premature loss of deciduous teeth.
Prolonged retention of deciduous teeth.
Delayed eruption of permanent teeth
Abnormal eruptive path
Ankylosis
Dental caries
Improper dental restorations