in the name of god - bpums.ac.ir · 2016. 10. 8. · reference: *contemporary orthodontics chapter...
TRANSCRIPT
In the name of GOD
Orthodontic indices and Epidemiology of
malocclusion
Presented by:
Dr Somayeh Heidari
Orthodontist
Reference:
*Contemporary Orthodontics
Chapter 1
William R. Proffit, Henry W. Fields, David M.Sarver. Fifth Edition 2013. MosbyWilliam R. Proffit, Henry W. Fields, David M.Sarver. Fifth Edition 2013. Mosby
How much deviation from the
ideal occlusion
should be accepted within the bounds of normal?
Prevalence of malocclusion in the USA (1930- 1965)
35% 95%
Advantages of Angle’s classification
• simple
• clear
• assessment of antero-posterior dental relationships
Limitations of Angle’s classification
Anteroposterior dental arches discrepancies
≠≠
Anteroposterior facial imbalances
Limitations of Angle’s classification
No assessment of vertical and horizontal inter-arches problems.
Antero-posterior or Sagittal plane
•molars relationship ( class I / II / III )
• canines relationship ( class I / II / III )
• incisors relationships ( overjet / anterior cross bite)
Horizontal plane
• upper to lower midlines
• posterior cross bite (buccal or lingual)• posterior cross bite (buccal or lingual)
Vertical plane
• overbite (deep bite or open bite)
Limitations of Angle’s classification
No assessment of intra- arch problems
•malalignment (crowding, rotation, spacing, …)
•missing
• impaction
• …
Dental Aesthetic Index (DAI)
crowding
spacing
overjet
overbite
molars relationship
Index of Orthodontic Treatment Need (IOTN)
1- dental health component
derived from occlusion and alignmentderived from occlusion and alignment
2- esthetic component
derived from comparison of the dental appearance to
standard photographs
IOTN : Dental health component
• overjet
• over bite
• cross bite• cross bite
• crowding
• impaction
•missing: hypodontia
• craniofacial anomalies: cleft lip and palate , ...
IOTN: Dental health component
IOTN : Dental health component
Grade 5: Extreme / need treatment
Grade 4: Sever / need treatment
Grade 3: Moderate / borderline need
Grade 2: Mild / little need
Grade 1: No need
IOTN: Esthetic component
IOTN : Esthetic component
1 – 4 : no/slight need
5 – 7 : moderate/borderline need
8 – 10 : definite need
• IOTN grades seem to reflect clinical judgments better than previous
methods
• There is a surprisingly good correlation between treatment need
assessed by dental health and esthetic components of IOTN
Epidemiology of the usual orthodontic problems
Incisors alignment
in the age 8-11 years old, just over half of US children have well aligned incisors.
the percent with excellent alignment decreases in the age 12- 17 years as the
remaining permanent teeth erupt.remaining permanent teeth erupt.
incisors alignment remains essentially stable in the upper arch but worsens in
the lower arch for adults.
only 34% of adults have well aligned lower incisors.
Nearly 15% of adolescents and adults have severely or extremely irregular
Incisors alignment
Nearly 15% of adolescents and adults have severely or extremely irregular
incisors.
Maxillary diastema
a wide space between the maxillary central incisors often is present in childhood:
26% have >2mm space
this space tends to close but over 6% of youths and adults still have a noticeable
diastema.
Maxillary diastema
blacks are more than twice as likely to have a midline
diastema than whites and Hispanics.diastema than whites and Hispanics.
Posterior cross bite
posterior cross bite is relatively rare at all ages.
overjet
overjet of 5mm or more, suggesting Angle’s class II malocclusion, occurs in
23% of children
15% of youths
13% of adults
overjet
reverse overjet, indicative of class III malocclusion, is much less frequent:
about 1% of American children and increases slightly in youths and adults.
overjet
sever class II and class III problems occur in about 4% of the population.
sever class II problems is much more prevalent. sever class II problems is much more prevalent.
sever class II problems are less prevalent, and sever class III problems are
more prevalent in the Hispanic than the white and black groups.
overbite
• vertical deviations from the ideal overbite of 1-2mm are less frequent in adults
than children but occur in half of adult population, the great majority of them
have deep bite.
• sever deep bite (overbite ≥ 5mm) is found in nearly 20% of children
13% of adults
while open bite (negative overbite > -2mm) occur in less than 1%
overbite
• there are striking differences between the racial / ethnic groups in vertical
dental relationships.
• sever deep bite is nearly twice as prevalent in whites as blacks or Hispanics.
• open bite > 2mm is five times more prevalent in blacks than the whites and• open bite > 2mm is five times more prevalent in blacks than the whites andHispanics.
• despite their higher prevalence of antero-posterior problems, vertical problems
are less prevalent in Hispanics than either blacks or whites.
normal occlusion
class I malocclusion
30%
15%
1%
class I malocclusion
class II malocclusion
class III malocclusion
50-55%
class II problems are most prevalent in whites of northern Europe
class III problems are most prevalent in Oriental population
class III and open bite are more frequent in African than European class III and open bite are more frequent in African than European
population deep bite less frequent
Why is malocclusion so prevalent?
present prevalence of malocclusion is several times greater than it was only
a few hundred years ago.
crowding and malalignment of the teeth were uncommon but the majority
of a group might tend toward a mild antero-posterior or transverse discrepancies
, such as a class III or less commonly a class II jaw relationships., such as a class III or less commonly a class II jaw relationships.
the fossil record documents a decrease in the size of teeth,
decrease in the number of teeth, and a decrease in the size
of jaws.
the third incisor and third premolar have disappeared, as has the fourth molar
at present, the human third molar, second premolar, and second incisor often fail to
develop, which indicates that these teeth may be on their way out
the progressive reduction in jaw size, if not well matched to a decrease
in tooth size and number, could lead to crowding and malalignment.
malocclusion may be on of the “diseases of civilization”
increasing malocclusions perhaps resulting in part from less use of the increasing malocclusions perhaps resulting in part from less use of the
masticatory apparatus with softer foods now.
Although it is difficult to know the precise cause of any specific malocclusion,
we do know in general what the etiologic possibilities are.
What difference does it make if you have a malocclusion??!! What difference does it make if you have a malocclusion??!!