1. Epidemiology of Malocclusion
Dr. Nabil Al-Zubair

2. The prevalence of malocclusions in modern populations

3. Orthodontic Anomalies of any kind and malocclusions are relative
infrequently analyzed in bio-archaeological investigations
There are at least three reasons for this

4. First:
orthodontic anomalies and
malocclusions are not recognized by
bioarchaeologists, anthropologists,
and related scientists as an important
and useful source of data about the
oral and general health of ancient
populations, as well as an important
source of data about other aspects of
their everyday life
‫لم يتم التعرف على حاالت سوء اإلطباق بواسطة‬
،‫علماء اآلثارالبيولوجية، علماء األنثروبولوجيا‬
‫كمصدر مهم ومفيد من البيانات حول صحة الفم‬
‫والعامة من الشعوب القديمة، وكذلك مصدرا‬
‫مهما للبيانات عن الجوانب األخرى من حياتهم‬
‫اليومية‬

5. Second:
Scientists involved in the examination of skeletal remains derived
from archaeological contexts usually do not have enough
knowledge for the identification (diagnosis) of orthodontic
anomaliesor for the interpretation of malocclusions
‫العلماء المشاركين في دراسة بقايا الهياكل العظمية المستمدة من‬
‫سياقات األثرية عادة ليس لديهم ما يكفي من المعرفة لتفسير سوء‬
.‫اإلطباق‬
Dentists, as experts educated in the diagnosis and
interpretations of orthodontic status are rarely
involved in bio-archaeological investigations.
.‫أطباء األسنان، وخبراء التشخيص نادرا ما يشاركوا في التحقيقات األثرية‬

6. Third: ‫حتى عندما يتم التعرف على أهمية تقويم األسنان، وأنها هي‬
even when the importance of ‫محور التحقيق، وحتى لو أحد الباحثين هو طبيب أسنان، هناك‬
orthodontic anomalies is recognised, ‫مشكلة هامة هي: عدم وجود عينات صالحة لالستعمال‬
and they are a focus of the
investigation, and even if one of the
researchers is a dentist, there is the
final and possibly most important
problem: the lack of usable samples
Papers and reports about
malocclusions and orthodontic
anomalies in skeletal populations
from archaeological contexts are
relatively rare and often based on
small samples

7. Although Malocclusion Now Generally Occurs In Much Of The Population, this was not always the case.
Skeletal remains show that malocclusions were relatively unusual before the 19th and
20th centuries

8. However Malocclusions were not absent
ً‫اإلنسان البدائ‬ Neanderthal specimen CROWDING , although the
estimated to be 100,000 Neanderthals had little rotation and
years old displacement of teeth with close a
proximal contacts
ancient skull dated about Impacted maxillary canines
7250 to 6700 BC. congenitally missing third molars
since Medieval Times
Several reports found increases in
‫العصور الوسطى‬
the frequency of malocclusion
the last 150 years increases in malocclusion frequency
seem to have accelerated in modern
industrialized societies , after only
modest changes for 6000 years

9. Problems of Dental Public Health
Caries Periodontal Malocclusion others
disease
Malocclusions are THIRD in the ranking of priorities among the problems of
Currently
dental public health worldwide, surpassed only by dental cavity and
periodontal diseases
with the reduction of caries in children and adolescents in recent decades,
However,
this condition has received more attention

10. ‫الدراسات االستقصائية‬
Many organized surveys have been carried out in different parts of the world
with the objective of
Estimating prevalence of malocclusion & orthodontic treatment needs
The ultimate goal being to identify etiologic factors
Prevalence is when
something is widespread
The total number of cases of
a condition in a given
population at a specific time

11. Prevalence of malocclusion
Country % of malocclusion
Chinese children 67.82
Nigeria children 84 % Class I malocclusion
1.7 % Class II malocclusion
Indian Children 19.6 %
American 34 % whites
15 % blacks
is estimated to be HIGHER in
Developed countries > developing & under-developed countries

12. Measurement of malocclusion
Malocclusion & dento-facial deformity are conditions that
‫تشكل خطرا على المحافظة على صحة الفم واألسنان‬
- Constitute a hazard to the maintenance of oral health
- Interfere with the well being of the person by adversely
affecting dento-facial aesthetics, mandibular function or speech

13. Measurement of malocclusion
as a public health problem is extremely difficult
since most orthodontic treatment is undertaken for AESTHETIC REASONS
It is very difficult to estimate the extent to which malposed teeth or
dento-facial anomalies constitute a psychological hazard
‫من الصعب للغاٌة تقدٌر المدى إلى أي حد ٌشكل سو اإلطباق مشكلة نفسٌة‬

14. Malocclusion has proved to be a difficult entity to define
because
individual perceptions of what constitute a malocclusion problem differ widely
‫تختلف التصورات الفردية فبما يعتبر مشكلة سو اإلطبلق على نطاق واسع‬
As a result
No generally accepted
epidemiological index of
malocclusion has yet
been devised

15. Malocclusion is not an acute condition
therefore
Treatment of malocclusion has been associated with a great degree of subjectivity
and distorted perceptions of treatment need

16. EPIDEMIOLOGY OF MALOCCLUSION
"‫"دراسة لديناميكية حدوث حالة أو سمة في مجتمع أو مجموعة‬
NHANES III USPHS survey
• “study of the dynamics of occurrence of a
(1989-1994) condition or trait in a population or
(1963, 1969 &1970)
group”
14,000 individuals surveyed
data on :
provides current information Epidemiology 6 - 11 and 12 -17 year-
on children, adults and major
old children
ethnic groups

17. Current Malocclusion Prevalence Data
NHANES III ( National Health And Nutrition Estimates Survey III) 1989-1994
Study design
 14,000 individuals sampled
 Target population of 150,000,000
 Statistically designed weighted
samples
 75% Whites, 11% African Americans
and 8% Hispanics

18. WHAT IS MALOCCLUSION?
 Malocclusion is not a disease,
but a spectrum representing biological
variability/diversity
 When the deviation from the
normal reaches a certain degree of
severity (threshold), then it is
termed malocclusion
 What is of relevance is “clinically significant” deviation from normal occlusion

19. NORMAL
OCCLUSION

20. 20%
Mild 35%
Normal
5%
20% 20%
Moderate
20%
Severe 20% 5%
20% Handicapped
Malocclusion

21. A handicapping malocclusion
DEFINITION: Abnormal dental development with at least one of the following:
(a) A medical condition and/or a nutritional
deficiency with medical physiological impact,
that is documented in the physician progress
notes that predate the diagnosis and request
for orthodontics.
The condition must be non-responsive to
medical treatment without orthodontic
treatment.
(b) The presence of a speech pathology, that is documented in speech therapy progress notes
that predate the diagnosis and request for orthodontics.
The condition must be non-responsive to speech therapy without orthodontic treatment.

22. (c) Palatal tissue laceration from a
deep impinging overbite where
lower incisor teeth contact palatal
mucosa.
This does not include occasional
biting of the cheek

23. COMPONENTS OF MALOCCLUSION
 Sagittal or Antero-
posterior
 Vertical
 Transverse
 Intra-arch
(crowding/spacing)

24. NHANES III TRAITS
‫الصفات‬
 Irregularity index
 Midline Diastema (spacing)
 Posterior cross-bite (transverse)
 Overjet (antero-posterior)
 Overbite/ Openbite (vertical)

25. IRREGULARITY OR CROWDING

26. DIASTEMA

27.  Little more than 50% surveyed had little or no
IRREGULARITY and DIASTEMA crowding with about 6-8 % exhibiting severe to
extreme crowding in the younger age group
Irregularity increased between childhood and  26% had maxillary midline diastemas in the
youth, and was largely stable between youth 8-11 age group, which decreased to 6% in
and adult EXCEPT for mandibular crowding later age groups
which increased

28. ANGLE’S CLASSIFICATION –
Antero-posterior component
Class I malocclusion Class II malocclusion Class III malocclusion
ANTERO-POSTERIOR COMPONENT

29. Antero-Posterior Dimension
Class II
Overjet 8-11 yrs 12-17yrs 18-50 yrs
10mm 0.2 0.2 0.4
7-10 3.4 3.5 3.9
5-6 18.9 11.9 9.1
3-4 45.2 39.5 37.7
Ideal 1-2 29.6 39.3 43.0
Class III
0 2.2 4.6 4.8
-1 to -2 0.7 0.5 0.7
-3 to -4 0 0.6 0.2
-4 0 0 0.1

30. Antero-Posterior Dimension, By Ethnicity
Class II
Overjet EA AA Hispanic
10mm 0.3 0.4 0.4
7-10 3.8 4.3 2.2
5-6 10.1 11.8 6.5
3-4 38.0 39.8 49.0
Ideal 1-2 42.4 35.6 33.6
Class III
0 4.1 6.1 6.7
-1 to -2 0.5 1.5 0.9
-3 to -4 0.2 0.4 0.4
-4 0.1 0.1 0.3

31. VERTICAL COMPONENTS TRANSVERSE COMPONENT
NORMAL OCCLUSION
LINGUAL POSTERIOR CROSS BITE

32. PREVALENCE
 Vertical problems of anterior open bite versus
anterior deep bite exhibits RACIAL DIFFERENCES
 Anterior open bites  Anterior deep bites
affect significantly are more common
larger number of in European-
African-Americans Americans

33. SUMMARY OF PREVALENCE
 30% had normal Class I occlusion  15-20% had Class II malocclusions
 50-55% had Class I malocclusions (crowding)  Less than 1% had Class III malocclusions
Class II malocclusions Normal Class I occlusion
 Class II problems were
most prevalent in
Class I malocclusions (crowding)
people of European
descent
 Class III problems were MORE prevalent in the African American, Hispanic and East Asian populations

34. For many years,
Epidemiologic studies of malocclusion suffered from:
considerable DISAGREEMENT among the investigators
100 % of malocclusion
The considerable variations 90
in malocclusion frequency 80
and treatment need relate to: 70
- different ages, 60
- genetics,
50
- methods of registrations.
40
- the size and composition
30
of the group studied (for
example age and racial 20
characteristics), 10
0
1930 1945 1955 1965
Prevalence of malocclusion in the United States

35. Prevalence of crowding
70
60
50 Age= 13
n= 200
40 Age= 13
Age= 10 -12 n= 200
30 n= 479
20 Age≥20 Age= 12
n=669 n= 5744
10
0
Libya Jordan Jordan Iraq
(Max. (Mand. Iraq Sweden
ant) (Max. (Mand. Sweden South
ant) ant) Male Female
ant) Africa

36. Mean overjet and prevalences of increased overjet
16
14
12
10
mean OJ
8
OJ ≥ 6
6
4
2
0
Jordan America England Iraq

37. Evolution
 There was a tendency to decreased size and number of teeth
 Modern Humans have underdeveloped jaws
 Imbalance between the progressive decreased jaw size and tooth
size can lead to teeth crowding or spacing
 Less use of masticatory forces with softer food could have lead to
an increase in malocclusion

38. Need for orthodontic treatment
Protruding, IRREGULAR, or MALOCCLUDED TEETH
can cause three types of problems for the patient:
‫التمٌٌز‬
1- Discrimination because of facial appearance
2- Problems of Oral functions and TMD
3- Greater susceptibility to trauma,
periodontal disease, or tooth decay

39. • Psychological problems
Malocclusion is likely to be a social handicap
‫ٌحتمل أن ٌكون عائقا اجتماعٌة‬
 Well-aligned teeth and  Appearance makes a
pleasing smile carry difference in teachers'
Positive Status to all expectations and therefore
social levels student progress, in
employment and in
competition for a mate.
 An individual who is grossly disfigured can anticipate a consistently Negative Response.
‫مشوه‬

40. • Oral function
Severe malocclusion can
Compromise mastication as in open bite cases
certain sounds might be impossible to be
produced and patients usually need speech
therapy (as in Cleft lip/palate patients)
(Class III, anterior open bite, posterior cross
bite and rotated/tipped teeth) correlate
positively to TMD
So, Malocclusion + TMD may indicate the need for orthodontic treatment

41. Relationship to injury and Dental diseases
 Malocclusion contributes to caries and
periodontal disease by increasing the areas of
food stagnation.
 Trauma from occlusion due to improper
alignment of teeth can cause periodontal
diseases.
 Protruded incisors as in Class II Division 1
malocclusion, can make the patient more prone
to trauma than well-aligned incisors.

42. Epidemiologic estimate of orthodontic treatment need and demand:
: ‫تقدير الحاجة والطلب إلى عالج تقويم األسنان‬
 About 35 % of adolescents are perceived by
parents and peers as needing orthodontic
treatment
 Dentists recommend treatment for another 20%
 There is more orthodontic need in urban areas
than in rural areas
 Demand for orthodontic need is correlated to family income

43. Occlusal indices

44. Occlusal indices
Diagnostic Epidemiologic Treatment needs Treatment outcome Treatment complexity
indices indices indices indices Index

45. Occlusal indices
Diagnostic Epidemiologic Treatment needs Treatment outcome Treatment complexity
indices indices indices indices Index
Dental esthetic DAI components include:
index (DAI), Cons 1. Number of visible missing teeth (incisors, canines and premolars in
(1986) maxillary and mandibular arch).
2. Incisal segment crowding
3. Incisal segment spacing
4. Midline diastema
5. Maxillary anterior irregularity
6. Mandibular anterior irregularity
7. Maxillary overjet
8. Mandibular overjet
9. Vertical anterior open bite
10. Anteroposterior molar relationship

46. Occlusal indices
Diagnostic Epidemiologic Treatment needs Treatment outcome Treatment complexity
indices indices indices indices Index
DAI score Severity levels
Normal or minor malocclusion
 25
No treatment need or slight need
Definite malocclusion Treatment elective
26 – 30
Severe malocclusion Treatment highly desirable
31 – 35
Very severe (handicapping) malocclusion
 36 Treatment mandatory

47. INDEX OF ORTHODONTIC TREATMENT NEED IOTN
It has two components
A. Dental health component (DHC):
has five grades
Grade 1—none: variations in occlusion
including displacement less than or
equal to 1 mm.
Grade 2—little
Grade 3—moderate
Grade 4—great
Grade 5—Very great
B. Esthetic component of IOTN

48. Dr. Nabil Al-Zubair