International Dental Journal (2003) 53, 13-18
Malocclusionand orthodontic
treatment need of handicapped
individuals in South Canara, India
Dinesh Rao B, Arnitha Hegde M and A.K. Munshi
Mangalore, India
Aims: To estimate the prevalence and the severity of malocclusion and
treatment need for 329 handicapped individuals. Subjects and setting:
329 handicapped individuals aged 11-30 years, attending eight different
nonresidential special schools of South Canara, India. Method: Examination and recording using the Dental Aesthetic Index (DAI). Results: 53%
had a dental appearance which required no orthodontic treatment, 24% had
a definite malocclusion,where treatment was ‘elective’ and treatment for a
further 12%was consideredto be ‘highly desirable’. The remaining subjects
(11Yo)had a handicapping malocclusionwhere treatment was considered
mandatory. Conclusions: The prevalence of definite and severe
malocclusions was higher in the mentally subnormal individuals when
compared to other handicapping conditions. Orthodontic services for the
handicapped have generally been neglected.
Key words: Malocclusion, handicapped, oral health, Dental Aesthetic index
Correspondence to: Dr. Dinesh Rao B, 2-156(4), Subhas Nagar Kuthar, Munnur Post,
Mangalore - 574 183, Karnataka State, India. E-mail dineshraoG3 rediffmail.com
0 2003 FDlMlorld Dental Press
0020-6539/03/01013-06
India is the second most populous
nation, with an estimated population of about over one billion. Even
though the latest exact number of
handicapped individuals is not
known, the gravity of the situation
can be judged as every year about
200,000 children become handicapped due to poliomyelitis alone’.
According to the National Sample
Survey of 1981, about two per cent
of the population was mentally
handicapped, while another 1.8 per
cent was physically, visually or hearing impaired2. According to the
1991 census there were nine million
children, either suffering from
mental subnormality or with
disabilities that might have led to it.
The data collected by the Rehabilitation Council of India, the statutory body in bringing the handicapped into the mainstream of
society, points out the fact that there
are less than 800 special schools in
whole of the country, providing
services to an estimated 25,000
special children only. These statistics clearly show that that handicapped individuals in India are
neglected.
Two centuries ago, the famous
poet William Cowper stated
“Variety is the spice of life, that
gives it all its f l a v o ~ r ” To
~ . paraphrase him, occlusal variation is the
real spice of corrective treatment,
which gives it flavour. Salzman
stated, ‘The epidemiologic determination of a disease is the first
14
Table 1 Studies conducted on normal individuals in India
Author@) and year of study
Sample size and city
Age group
(in years)
Miglani and Sharma (1961)s
Jacob and Mathew (1969)7
Prasad et a/. (1971)8
Nagaraja Rao et a/. (1980)g
Jalili eta/.(1989)'O
Kharbanda et a/. (1995)"
Kharbanda el a/. (1 995)'*
Singh el a/. (1998)13
1158 (Madras)
1001 (Trivandrum)
1033 (Bangalore)
511 (Udupi)
1085 (Mandu)
2817 (Delhi)
2737 (Delhi)
1019 (Rural Haryana)
15-25
12-15
5-1 5
5-1 5
6-1 4
5-9
10-13
12-16
Malocclusion
(in percentages)
19.6
49.2
51.5
28.8
14.4
20.3
45.7
55.3
Table 2 Distribution of mentally subnormal individuals
Type of mental subnormality
1.Mild mental subnormality
2.Moderate mental subnormality
3.Severe mental subnormality
Total
step in public health endeavour^"^.
Although in India a number of
studies have been conducted to
estimate the prevalence of
malocclusion in normal individuals, it is quite difficult to estimate
the proportion that requires orthodontic treatment (Table
This
is due partly to the multiplicity of
measurement methods and the
difficulty in standardising criteria.
The lack of suitable universal methods for recording and grading
malocclusion and the different
criteria used to define malocclusion
have made comparison between
studies difficult. However, it is
unfortunate to find that occlusal
anomalies of handicapped children
have received scant attention. In
fact, for these children, it should
be possible to improve the
dentofacial apparatus, not only for
better oral functions, but also to
have a proper co-ordination within
society.
With the Dental Aesthetic Index
(DAI), the WHO has attempted
to establish a simple universally
acceptable index which can be used
in epidemiological surveys to assess
unmet orthodontic treatment need
and a screening tool for determining priority for orthodontic care in
public financed programme^'^. The
DAI is an orthodontic index that
International Dental Journal (2003) Vol. 53/No. 1
Total number
of individuals
Down syndrome
individuals
74
52
52
178
23 (31.08%)
24 (46.15%)
27 (51.92%)
74 (41.57%)
links clinical and aesthetic components mathematically to produce a
single scoreI5.
The aims of the present study
were to determine the prevalence
and severity of malocclusion, and
the treatment need as well as the
provisions that could be provided
to handicapped individuals attending different special schools of
South Canara District of Karnataka
State in India.
Materials and methods
The study population consisted of
329 individuals (202 males and 127
females) aged between 11-30 years
with a permanent dentition, attending eight special schools for the
handicapped in the South Canara
district of Karnataka State, India.
The representative sample belong
to the following eight major
disability groups:
Mentally subnormal individuals,
whose intellectual development and
ability to adapt to the environment
is significantly lower than that of
normal. This group contained both
Down syndrome as well as nonDown syndrome mentally subnormal individuals. This group was
further subdivided into mild,
moderate and severe mental
subnormalities based on the level
Non Down syndrome
individuals
51 (68.92%)
28 (53.85%)
25 (48.08°~)
104 (58.43%)
of the Stanford-Binet general intelligence test, as recorded by the
psychologist of the institutions at
the start of the academic year
(Table2)
Mild mentally subnormal (Mdd
MS) individuals, whose IQ is
between 52-67 (Educable mental. subnormal)
Moderate mentally subnormal
(Mod MS) individuals whose I Q
is between 36-51 (Trainable ment a l . subnormal)
Severe mentally subnormal (Sev
MS) individuals, whose IQ is
lower than 35 (nron trainable
mentalb subnormal)
Visually impaired (Vis 1) are
those with limited power of
vision, which restricts normal
activity to a certain degree
Hearing impaired (Hear 1) are
those with poor hearing levels
for speech, which restricts the
ability to understand language
Physically handicapped (Phy H)
individuals are those prevented
by a physical condition [from
full participation in normal
activities], such as muscular dystrophy, congenital limb defects,
etc.
Medical handicap (Med H) are
those with medical conditions
which put general health at
further risk, such as bleeding
15
Table 3
The standard DAI regression equation
DAl components
Weights
1.
Number of missing visible teeth (incisor, canine and premolar teeth in the maxillary and mandibular arches)
6
2.
Crowding in the incisal segments: O=no segment crowded, 1=1 segment crowded, 2=2 segments crowded
1
3.
Spacing in the incisal segments: O=no spacing, 1=1 segment spaced, 2=2 segments spaced
1
4.
Midline diastema in millimetres
3
5.
Largest anterior irregularity in the maxilla in millimetres
1
6.
Largest anterior irregularity in the mandible in millimetres
1
7.
Anterior maxillary overjet in millimetres
2
8.
Anterior mandibular overjet in millimetres
4
9.
Vertical anterior openbite in millimetres
4
10. Antero-posterior molar relation; largest deviation from normal either left or right: O=normal, 1=% cusp either
mesial or distal, 2= one full cusp or more either mesial or distal
3
13
11. Constant
Total
DAI Score
Table 4
The distribution of the handicapped subjects according to antero-posterior molar
relationships
Type of handicap
Total number
of individuals
1. Mild mental subnormality
2. Moderate mental subnormality
3. Severe mental subnormality
4. Visual impairment
5. Hearing impairment
6. Physical handicap
7. Medical handicap
8. Multiple handicap
Total
disorders, kidney disorders, etc.
Multiple handicap (Mult H) are
those with more than one variety of the listed disabilities.
Prior consent was obtained
from the respective school authorities and from the parents or guardians through the schools to conduct
the study. The handicapped subjects
were examined at their respective
schools, seated on an ordinary chair
unless they were confined to a
wheelchair, under natural light. All
examinations were conducted by a
single investigator, assisted by a
previously trained recording clerk.
The occlusal anomalies were
recorded as per the Dental Aesthetic Index, applicable only to the
permanent dentition", according to
the WHO guideline components"
and using all 10 measures (Table 3).
The data collated were analysed
and tested for significance using
statistical software packages, SPSS
74
52
52
12
68
38
20
13
329
Half cusp
Normal
37
38
33
8
51
30
15
10
222
(50%)
(73.08%)
(63.46%)
(66.66%)
(75%)
(78.95%)
(75%)
(76.92%)
(67.48%)
32
12
15
2
16
6
2
1
86
(version 6.0) and Arcus Differences
in frequencies between the groups
were tested by means of the 'Chisquare test'.
Results
The distribution of the study population based on the anterio-posterior molar relations is given in
Table 4. Of the 329 subjects examined, 222 (67.48 per cent) presented
with normal molar relationships,
86 (26.14 per cent) with half cusp
and 21(6.38 per cent) with full cusp
relationships respectively. The
prevalence of half cusp and full
cuspal molar relations were significantly higher among the mentally
subnormal individuals when
compared to other handicapping
conditions (x' = 8.179, p<O 01).
The prevalence of normal molar
relationship in the mild mental
subnormal group was lower, when
(43.24%)
(23.08%)
(28.85%)
(16.67%)
(23.53%)
(15.79%)
(10%)
(7.69%)
(26.14%)
Full cusp
5 (6.76%)
2 (3.84%)
4 (7.69%)
2(16.67%)
1 (1.47%)
2 (5.26%)
3(15%)
2 (15.39%)
21 (6.38%)
compared to the moderate
mentally subnormal, hearing
impaired, physically handicapped
and medically handicapped groups
respectively
Open bite was observed in nine
individuals (2.74 per cent), of
which eight subjects were mentally
subnormal (Table 5). Nine subjects
(2.74 per cent) were found to have
an anterior cross bite with eight of
them being mentally subnormal
(Table 5).
Anterior overjet greater than
2mm was observed in 150 individuals (45.59 per cent) of whom
95 were mentally subnormal (?'able
5). The prevalence of increased
overjet was higher in the mentally
subnormal when compared to
other handicapping conditions,
which was statistically significant (x'
= 9.459,pcO.Ol).
The frequency distribution of
other malocclusion traits based on
Dinesh et a/.:Orthodontic treatment need of handicapped individuals
16
Table 5
The number and percentage of the handicapped subjects with increased overjet, open bite and
anterior cross bite
Type of handicap
Total number
of individuals
1. Mild mental subnormality
74
52
2. Moderate mental subnormality
3. Severe mental subnormality
52
4. Visual impairment
12
5. Hearing impairment
68
6. Physical handicap
38
7. Medical handicap
20
8. Multiple handicap
13
Total
329
Table 6
Anterior overjet
(23mm)
Anterior open bite Anterior cross bite
(2 Omm)
(2 Omm)
47
23
25
4
27
13
(63.51%)
(44.23%)
(48.08%)
(33.33%)
(39.7%)
(34.21%)
6 (30%)
5 (38.46%)
150 (45.59%)
(2.7%)
(1.92%)
(9.62%)
3
2
3
0
1
0
0
0
9
(7.69%)
(2.74%)
(4.05%)
(3.85%)
5.77%)
(1.47%)
(2.74%)
The frequency distribution of other malocclusion traits
according to DAI components (n=329)
DAI Component
Missing teeth
Crowding (incisal segments)
Spacing (incisal segments)
Diastema (mm)
Anterior maxilary irregularity (mm)
Anterior mandibular irregularity (mm)
21
1-2
1-2
21
21
21
Frequency
%
46
130
134
101
104
117
(13.98)
(39.51)
(40.73)
(30.7)
(31.61)
(35.56)
Table 7 The number and percentage of the subjects with dento-facial anomalies by the level of severity
Type of handicap
Total number
No abnormality or Definite malocclusion Severe malocclusion Very severe or
(DAI score 31-35)
handicapping
of individuals minor malocclusion (DAI score 26-30)
(DAI score 125)
malocclusion
(DAI score 236)
1. Mild mental subnormality
2. Moderate mental subnormality
3. Severe mental subnormality
4. Visual impairment
5. Hearing impairment
6. Physical handicap
7. Medical handicap
8. Multiple handicap
Total
74
52
52
12
68
38
20
13
329
the DAT components is shown in
Table 6. One or more missing anterior teeth were noted in 13.98 per
cent of the total study population.
Incisal crowding and spacing
was frequently measured at 39.51
and 40.73 per cent respectively.
Median diastema, occurred in about
30 per cent of the total population
Anterior maxillary and mandibular
irregularities were measured at
31.61 and 35.50 per cent respectively.
As per the DAI scores, the
entire population sample of 329
was distributed into four groups.
Over half of the study group (53.49
per cent) had a dental appearance
where orthodontic treatment need
International Dental Journal (2003) Vol. 53INo.l
30
32
20
5
44
27
13
5
176
(40.54%)
(62.54%)
(38.46%)
(41.66%)
(64.71%)
(71.05%)
(65%)
(38.46%)
(53.49%)
21 (28.38%)
8(15.39%)
12(23.08%)
2(16.67%)
20 (29.41%)
5 ( 13.1 6%)
4 (20%)
6(46.15%)
78 (23.71 %)
was ‘slight’ or ‘not indicated’. A
substantial portion (23.71 per cent)
of the population had ‘definite
malocclusion’, where treatment
need was elective. However, over
12 per cent fell into the group of
‘severe malocclusion’, where treatment was considered to be ‘highly
desirable’. The rest of the sample
(10.64 per cent) had ‘handicapping
malocclusion’ where treatment was
mandatory (Table 7).
The prevalence of definite, severe
and handicapping malocclusions
were higher in the mentally subnormal group, compared to other
handicapping conditions, which
was ‘statistically significant
8.6,
p<O.Ol).
a2=
13 (17.57%)
4 (7.69%)
12(23.08%)
3 (25%)
2 (2.94%)
4 (10.53%)
2(10%)
0 (0%)
40 (12.1 6%)
10
8
8
2
2
2
1
2
35
(13.51%)
(15.38%)
(15.38%)
(16.67%)
(2.94%)
(5.26%)
(5%)
(15.39%)
(10.64%)
Discussion
Nature is infinitely variable. The
human species comprising of
varied racial and ethnic groups are
distinct in several aspects of
dentofacial morphology5. Ideal
occlusion, a hypothetical concept
based on the anatomy of the teeth,
is rarely found in nature. Thus, to
be able to treat any malocclusion
we must know the nature and
features of the same.
McLain and Proffit have stated,
‘Occlusal .... problems cannot be
defined solely in physical terms””.
The psychosocial consequences of
malocclusion due to unacceptable
dental aesthetics may be as serious
17
or even more serious than the
biological problems'". Thus the
Dental Aesthetic Index (DAI) is an
orthodontic index based o n
socially defined aesthetic standards'", even though a limited
number o f studies have been
reported using it.
Although there is considerable
information available about the
occlusal pattern of normal children,
there is a paucity of comparable
information about handicapped
individuals. Also, comparison
between different studies is difficult because of a lack of common
indices. In their literature review,
Brown and Schodel found that
except for individuals with Down
syndrome and severe cerebral palsy,
there was n o clear evidence that
malocclusion was common
amongst the handicapped'".
In our present study, the
mentally subnormal had a proportionally lesser number o f the
individuals with normal molar
relations when compared to other
groups. This may be due to a large
number o f D o w n syndrome
subjects included in this group.
The mentally subnormal subjects
had increased frequencies of anterior open bite and cross bite
respectively when compared to
other handicapped subjects. Vigild
reported 38 per cent anterior open
bite and 41 per cent anterior cross
bite in Down syndrome individuals and 23 per cent anterior open
bite, 29 per cent cross bite in nonDown syndrome mentally subnormal subjects respectivelf'.
Many aetiological factors have
been associated with the high incidence o f open bite among
mentally subnormal individuals.
Deficient maxillary growth and
abnormal tongue size have been
reported as the contributing
factors in the production of anterior open bite in Down syndrome
individuals''~'3. Also, a mentally
subnormal child is sensitive and
more vulnerable to stress because
he or she has inadequate concepts
of his or her environment. This
may result in emotional insecurity
and forces the child to diversify
into deleterious oral habits, such as
thumb sucking, tongue thrusting,
etc. These habits bring about harmful unbalanced pressures to bear
upon the immature, highly malleable alveolar ridges, the potential
changes in position of teeth and in
occlusions.
The mentally subnormal group
had a proportionally greater
number of the individuals with
severe and handicapping malocclusion especially when compared to
those with visual and hearing
impairments. A correlation seems
to exist between the incidence of
mental subnormality and the
severity of craniofacial handicap,
and thus, displays a higher incidence
of malocclusion than other handicapped
Oral
dysfunctions and parafunctions of
the masticatory system were
hypothesised as being responsible
for the increased prevalence of
malocclusion in mentally subnormal individuals". Mental status,
therefore, appeared more decisive
for the orthodontic status than a
common medical diagnosis.
Orthodontic treatment services
for the handicapped have been
neglected for a long time. Individuals with sensory and physical
disabilities come closest to being
'normal' and probably are able to
co-operate and can accept orthodontic mechanotherapy. T h e
mentally subnormal and those with
multiple handicaps are more difficult to manage and so it may not
be surprising to have more individuals in those groups requiring
urgent attention. The correction or
trainability of an abnormal oral
function will be crucial for the
stability of orthodontic treatment
in cases in which the particular function is a causative factor in the
malocclusion". The parents should
be informed about the existing
malocclusion and the long-term
risks of deleterious oral habits. An
improved accessibility to orthodontic services as well as oral health
education is necessary to ensure that
optimum oral health is within the
reach of these less fortunate individuals.
Conclusions
The present study provides an
insight into the dentofacial varieties
in the different handicapped individuals of South Canara district of
Karnataka State, India and forms a
basis for comparison with other
studies. The following conclusions
can be drawn:
The prevalence of definite and
severe malocclusions was higher
in the mentally subnormal individuals when compared to
other handicapping conditions.
Increased frequencies of anterior open-bite, overjet and cross
bites were noted among the
mentally subnormal subjects
respectively.
Normal molar relationships
were less prevalent in the mentally subnormal subjects when
compared to other handicapping conditions.
Orthodontic services for the
handicapped have generally been
neglected.
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