Epidemiological indices - Dr. Shubham Narnoli

By:- Dr. Shubham Narnoli
PG 1st year
Department of Orthodontics and DentofacialOrthopedics

1. Occlusal Feature Index (Poulton & Aaronson, 1961)
2. Index ofTooth Position (Massler & Frankel, 1951)
3. Malalignment Index (Van Kirk & Pennel, 1959)
4. The Bjork Method (1964)
5. Summers’Occlusal Index (1971)
6. The FDI method (Baume et al, 1973)
7. Little’s Irregularity Index (1975)
8. Handicapping Labio-lingual Deviation index (HLD) (Draker, 1960, 1967)
9. Swedish Medical Board Index (SMHB 1966; LinderAronson, 1974, 1976)
10. Dental Aesthetic Index (DAI) (Cons et al, 1986)
11. Index of Orthodontic treatment Need (IOTN) (Brook & Shaw, 1989)
12. Index of Complexity, Outcome & Need (ICON) (Daniel & Richmond, 2000)
13. Peer Assessment Rating Index (PAR) (Richmond et al, 1992)

 An index must be simple, reproducible, and objective.
 EpidemiologicApproach.-The basic difference in the viewpoints of the
clinician and the epidemiologist largely determines the different
methods used by each.
 The clinician is concerned with the person suffering from the disease
(i.e., the effects of the disease upon the individual) while the
epidemiologist is primarily concerned with the characteristics of the
disease itself (i.e., its extent, pattern of distribution, and behavior).To
the epidemiologist, the patient is an abstract concept called “the average
person. ”

 DONALD R. POULTON, D.D.S.,”AND SANFORD A. AARONSON, D.D.S.“
 Achieving the ideal in tooth form, tissue contour, and facial harmony is
the ultimate goal of treatment procedures in the various branches of
dentistry.
 Because of the clinical importance of the relationship between occlusion
and periodontal status, a survey was undertaken to measure the
incidence of these variables in a population group.

 Massler and Frankel provided an excellent historical review of the problem and
proposed an index based on the unit of occlusion.
 A score for each individual is obtained on the basis of the number of maloccluded
teeth observed.
 Because this examination is made with the mouth open and the alignment is evaluated
only from the occlusal aspect, scoring is easier and probably more consistent.
 Method appears to measure malocclusion indirectly, though, since the score is not
affected in any way by the relationship of the upper and the lower teeth in
occlusion.

 Index of occlusion was developed at the National Institute of Dental
Research in 1957.
 The Occlusion Feature Index (OFI) is based on four primary features of
occlusion which are of importance in an orthodontic examination.
1. Lower anterior crowding
2. Cuspal interdigitation
3. Vertical overbite
4. Horizontal overjet

 In the canine-to-canine area
 0 - None
 1 - Crowding of lower anterior teeth equivalent to one-half the
width of the lower right central incisor
 2 - Crowding the width of one central incisor
 3 - Crowding exceeding the width of one central incisor

 Observed in occlusion looking at the right PM to M area
from the buccal aspect
 0 - Cusp-to-groove relationship
 1 - Between cusp and groove
 2 - Cusp-to-cusp

 Measured by that portion of the lower incisors covered by
upper central incisors in occlusion
 0 - Incisal third of lower incisors
 1 - Middle third of lower incisors
 2 - Gingival third of lower incisors

 Measured in occlusion with a small ruler from labial surface
of upper incisors to labial surface of lower incisors
 0 - 0 to 1.5 mm.
 1 - 1.5 to 3 mm.
 2 - 3 mm. and over

The possible range is from 0 to 9 ( by adding them together).
 Scoring done according following criteria:
1. Slight (0-1): No need for orthodontic treatment
2. Mild (2-3) : Some variation from ideal occlusion but not sufficient to
need treatment
3. Moderate(4-5): Orthodontic treatment indicated and would be beneficial
4. Severe(6-9): Treatment essential

 It seems justifiable to say, then, that these four simple observations,
which depend on easily defined criteria, yield a numerical score which
will agree very closely with the findings of an orthodontic examination.

 1. OFI described here appears to be a workable, meaningful means of
recording malocclusion in population studies.
 2. OFI scores on 152 subjects did not differ significantly when obtained
by two examiners, and they showed close correlation with a separate
need-for orthodontic-treatment rating.
 3. OFI and periodontal status scores were run on a group of 908 male
subjects and a significant correlation was shown, leading to the
hypothesis that malocclusion may be important in the etiology of early
periodontal disease.

 4. On the basis of these findings, each of the following features of occlusion
showed A significant relationship to periodontal status:
(A) vertical incisor overbite
(B) posterior cuspal interdigitation
(C) lower anterior crowding
(D) horizontal incisor overjet.

 This method is simple and is subject to statistical discipline.
 It was the purpose of this study to test the usefulness of this method and
to accumulate reliable epidemiologic data on the prevalence of
malocclusion in a group of children 14 to 18 years of age.

 Most of the methods of assessment were based upon Angle’s
designation of “normal ’’ and ‘‘ abnormal ’’ occlusion
 Most of the classifications used today are based upon Angle’s
designation of molar relationships and Class I, Class II. and Class III
malocclusions.
 A few include designation of the relationships of the anterior segments.

 This method uses the individual tooth as the unit of occlusion rather
than a segment of the arch.
 Each tooth is examined to determine whether it is in correct occlusion or
is maloccluded.The number of maloccluded teeth in each individual is
then counted and recorded.
 The total number of maloccluded teeth per person is the basis for the
evaluation of the prevalence and incidence of malocclusion in large
groups of individuals.

 Definition of maloccluded tooth - In 1907,Angle stated that a tooth could be
maloccluded in any one of seven positions or combinations of positions.
 These were described as:
1. Buccal (labial)
2. Lingual
3. Mesial
4. Distal
5.Torsoocclusion (rotation )
6. Infraocclusion
7. Supraoclusion
1. Buccal (labial) or lingual
displacement
2. Mesial or distal displacement
3. Rotated
4. Infraoccluded or supraoccluded

 A given tooth can therefore be in only one of three positions within the
arch : correct occlusion, malpositioned, or missing.
 If malpositioned, the tooth can be displaced in as many as four different
spatial relationships.
 For example, a tooth can be out of the line of occlusion both buccally
and distally; it can also be rotated and supraerupted, all at the same
time.
 The exact malposition of each tooth was noted by appropriate symbols
on the recording sheet

 The first examination consisted of an
inspection of each tooth from the occlusal
view of each arch in order to determine
best its relation to the adjacent teeth and to
the contact line – Buccal or Lingual

 Bite was registered-The interdigitation of the
teeth was then inspected from the buccal and
labial aspect in the occluded position.The
relation of each tooth to the plane of occlusion
was readily revealed by this inspection .
 This view readily revealed supra and infra
eruptions of the teeth.
 The mesiodistal relationships of the individual
teeth were also best discerned from this point
of view

 Thus a given tooth might have been recorded as having been malposed
in four different, ways, but was counted only once as one maloccluded
tooth.
 The number of maloccluded teeth in each individual was then counted,
and this figure used in all subsequent analyses.
 Given individual resulted in a number from zero (0) for a dentition with
no maloccluded teeth to twenty-eight (28) if all of the teeth were
maloccluded.
 Missing teeth were considered only as absent.

 During the analysis of the data it became apparent that the amount of
malocclusion in any population group will depend a great deal upon the definition
of what constitutes malocclusion.
 The mere presence of one or two very slightly displaced teeth which in no way
interfere with proper function or with esthetics does not constitute a
“malocclusion.”
 An analysis of the data showed that this subjective estimate of “normal” was
limited to patients with less than the average number of 10 malpositioned teeth.
 The designation of “malocclusion” was reserved for those patients in whom the
malpositioning of the teeth was sufficiently severe in degree to require
orthodontic treatment, and/or any case having more than 10 malpositioned
teeth.

 Class I malocclusion was the most common form of malocclusion.
Fifty per cent of all the children were thus affected.
 79 per cent of all the children showed some form of malocclusion.
 This means that 50 out of 79 (63.3 per cent) children with malocclusion
were Class I (Table II).
 Class II, Division 1 malocclusion was encountered in 16.7 per cent of total.
 Class II Division 1 malocclusion was encountered in 17 out of 79 (21.5 per
cent) children with malocclusion.
 Class III malocclusion was present in 9.4 out of 79 children with
malocclusions (11.9 per cent).

 The 2,758 children examined in this study had a total of 29,103 maloccluded
teeth or an average of 10.55 maloccluded teeth per child
 Sex differences -Boys were slightly but consistently more often affected
 The most frequently maloccluded teeth were the lower central incisors
 And, the least often maloccluded teeth, the upper first molars
 The fact that the upper first molar was least often maloccluded was
undoubtedly related to the fact that this tooth was used as a point of reference
for assessing the position of other teeth.

 The right side of the arch showed slight but consistently greater
numbers of maloccluded teeth than did the left side
 Greater number of maloccluded teeth were found in the lower arch.
 Greater number of maloccluded teeth in the anterior segments than in
the posterior
 Teeth most frequently lost by extraction were the lower first molars
 A missing tooth may be considered to be also a maloccluded tooth on
the basis that it contributes nothing to a good occlusion and, in fact,
fosters malpositioning of the adjacent teeth.

 The assessment method differs from that followed in a
routine clinical examination by an orthodontist or other
dentist.
 Neither a conventional dental chair nor an examination light
is used, although an adequate fixed source of light is
essential.

 A small plastic, gauge like tool especially designed for the work is the only
instrument used in making the necessary measurements for assessment.

 Malalignment of teeth was selected for measurement
because of the frequency of its occurrence.
 Scoring of individual tooth findings are summated for the
anterior and right and left posterior segments of each arch.
 A final malalignment index is obtained as the total of the six
segment scores.

 The segments are assessed in the following order:
1. Maxillary anterior
2. Maxillary right posterior
3. Maxillary left posterior
4. Mandibular anterior
5. Mandibular right posterior
6. Mandibular left posterior

 Each tooth present in a segment is scored 0, 1, or 2.
 Score 0 - for ideal alignment. Here the tooth shows no apparent deviation from
the ideal arch line as projected through the contact areas.

 Score 1 - minor malalignment of two
types.
1. Rotation - Angle formed by the line
projected through the contact areas of
observed tooth and the ideal arch line is
less than 450 .
2. Displacement- Both contact areas of the
tooth are removed in the same direction
from their position in ideal alignment but
less than 1.5 mm removed.

 Score 2 - major malalignments of
rotation and displacement.
1. Major rotation - Angle formed by the
line projected through the contact
areas of the observed tooth and the
ideal arch line is 450 or larger.
2. Major displacement - Both contact
areas of the tooth are removed from
their position in ideal alignment by 1.5
mm or more

 The plastic instrument is superimposed over the teeth for
the scoring measurements.
 The values are summated to give a score each segment.
 The final malalignment index is obtained as the sum of the
scores recorded for all six segments.

 The range of values may extend from 0 to 64 in mouths with
32 teeth present.
 2100 junior high school children
 12 and 15 years of age their average age was 13.9 years.
 Average malalignment score of 7.5, and the values scored
ranged from 0 to 21
 Average malalignment scores built up in an orderly fashion
as age increased.

 The contribution of the segment scores to the total
malalignment index built up to somewhat greater levels in
anterior than in posterior.
 Scores were greater in the mandible than in the maxilla.
 As age increase malalignment in posteriors increase more
than that in anterior.

 A thorough investigation of the occurrence of malocclusions among school-
children would be of major importance in the planning of orthodontic treatment
in the Public Dental Health Service.
 For this purpose it is necessary to have available detailed information on the
prevalence of individual malocclusions among boys and girls at different ages,
distributed regionally, and moreover, an analysis of the need for orthodontic
treatment in the different school classes.
 An analysis of such data collected from large groups of children would throw light
on the relationship between different types of malocclusion, widen our knowledge
of their etiology and hence increase the possibility of preventing them.

 An instrument for evaluation of certain
malocclusion. It consists of handle with
two blades, one of them 2 mm and the
other 1 mm in thickness.

 The thickness of blades used in the measurement of mandibular overjet,
openbite, spacing, transverse forced bite, displacement of the midline and
medial diastema.
 The thinner blade has one side of 21 mm in length and may be used in the
evaluation of spacing in the lateral sections.
 Maxillary overjet is measured with the transverse lines 6 and 9 mm from
the edge on the thicker blade.

 The longitudinal lines 5 and 7 mm from the edge on the same blade are
used in the evaluation of deep bite.
 Rotation of incisors is measured either by means of the sloping lines of
150 on the thicker blade or by the sloping end surface of the thinner blade
forming an angle of 150 with the end surface of the thick blade.

 The registration of the malocclusions is divided into three parts :
A. Anomalies in the dentition, i.e. tooth anomalies, abnormal eruption and
misalignment of individual teeth.
B. Occlusal anomalies, i.e. deviations in the positional relationship
between the upper and lower dental arches.
C. Deviations in space conditions, i.e. spacing or crowding of the teeth.

 Advantage –
1. Malocclusion may be described in terms of a combination of
well defined single symptoms within these three groups.
2. An indication of the need for orthodontic treatment is
included in the registration.
3. Data are recorded in code according to a table of code
numbers and the code numbers are entered on a special
form.

 Extreme maxillary overjet:
 Grade 1: 6 to 9 mm.
 Grade 2: 9 mm and over.
 Mandibur Overjet
 Grade 1: 0 to 2 mm.
 Grade 2: 2 mm and over.
 Distal molar occlusion:
 Grade 1: One-half to one cusp width.
 Grade 2: One cusp width and over.

 Mesial molar oclusion
 Grade 1: One-half to one cusp width.
 Grade 2: One cusp width and over.
 Vertical occlusion - 0penbite frontal:
Grade 1: 0 to 2 mm.
Grade 2: 2 mm and over.
 Openbite lateral

 Deep bite, frontal
grade 1: 5 to 7 mm.
Grade 2: 7 mm and over
 Transverse occlusion
 Crossbite
 Scissors bite
 Spacing conditions
 Crowding
 Spacing
(registered when there is a deviation of at least 2 mm in a section)

 Unrecordable Subjects:
1. Multiple extraction
2. Cases with too extensive caries
3. Severe pathological conditions

 If orthodontic treatment is indicated, the need for treatment, its type, duration
and time are registered.
 Type of treatment (one or more groups may be registered):
1. Observation
2. Instruction
3. Grinding of teeth
4. Extraction of deciduous teeth
5. Extraction of permanent teeth
6. Appliance therapy
7. Oral surgery

 Duration of treatment (only one of the groups is registered):
1. Minor treatment: less than 6 months.
2. Moderate treatment: 7-12 months.
3. Major treatment: longer than 12 months.
 Time for treatment:
1. Present: Treatment to be performed within 2 years.
2. Later: Treatment not for 2 years or longer.

 A method for epidemiological registration of malocclusion.
 The method consists in a systematic registration of carefully defined
individual symptoms.
 The registration of some of the symptoms is facilitated by using a
specially designed instrument.
 The need for treatment is also investigated but this registration is
necessarily subjective.
 The study has been designed with view to electronic analysis of the
data.

 Variations in terminology, concepts, and methodology can
be cited as the major reasons for the present lack of a
universally acceptable index of occlusion.
 For these reasons, a study was undertaken to attempt to
develop an index of occlusion,This index is called the
occlusal index (OI).

 A basic orthodontic defect may be defined as a constant occlusal
dysfunction which may exist before, during, and after the development
of occlusion.This defect may be
 (1) Skeletal, such as a mandible disproportionate in size to the maxilla.
 (2) Dental, such as a discrepancy in the size of the teeth and the jaw.
 (3) Neuromuscular, such as a tongue-thrust.

 The basic orthodontic defect usually is present before the development
of occlusion, although it may not manifest until after the mixed-dentition
stage.
 As an example, a skeletal Class II malocclusion at age 7 is still a skeletal
Class II malocclusion at age 16, and yet it was present at age 2.

 Symptom of a developmental defect - defined as an adaptation to
development.
 The symptom may either be constant (present at all ages) or variable
(fluctuating with age).
 An example of a symptom is the flaring and spacing of the maxillary
permanent incisors normally seen in the early mixed dentition.

 Nine characteristics are scored in the occlusal index:
1. Dental age
2. Molar relation
3. Overbite
4. Overjet
5. Posterior cross-bite
6. Posterior open-bite
7. Tooth displacement (actual and potential)
8. Midline relations
9. Missing permanent teeth.

 The purposes of describing these scoring procedures in detail are as
follows :
1. To standardize scoring procedures.
2. To indicate how each scoring procedure is mutually exclusive ; double
sc0ring is eliminated.
3. To enable investigators to apply subjective classifications to the
objective measurements, if needed for broad comparisons at a later
point in time.

Dental
age
Begins with Ends with Characteristic feature
0 Birth Eruption No erupted teeth
I Eruption of the first deciduous
tooth
When all deciduous teeth are in
occlusion
Development of the
deciduous dentition
Ii When all deciduous teeth are
in occlusion
The eruption of the first permanent
tooth
Completed deciduous
dentition
Iii Eruption of the first
permanent tooth
When all permanent central and
lateral incisors and first molars are
in occlusion
Early mixed dentition
Iv All permanent central and
lateral incisors and first molars
are in occlusion
Eruption of any permanent canine
or premolar
Middle mixed dentition.
V The eruption of any
permanent canine or premolar
When all the permanent canines
and premolars are in occlusion
Last stage of the mixed
dentition
Vi When all permanent canines
and bicuspids are in occlusion
Completed permanent
dentition

1. Defined “cut-off” points, where one type of relation ends and another
begins.
2. No classification intoAngle Class I, II, or III;Angle’s classification,
however, may be derived from these measurements.
3. The relation of the deciduous second (E) and permanent first molars (6)
is considered for each side.

 Five relations each for the deciduous and permanent molars were used.
 This is best described by considering dental age II (for the relation of E)
and dental ageVI (for the relation of 6). Morphologically, E and 6 are
similar, except that E is smaller than 6.

 The “cut-off” points are as follows :
 A. Deciduous teeth
 1. Mesial.The mesiobuccal cusp of E occludes with
the distobuccal cusp of E, as shown in Fig. 2, D.
 2. Distal.The mesiobuccal cusp of E occludes with
the mesiobuccal cusp of E, as shown in Fig. 2, B.

 B. Permanent teeth
 1. Mesial.The mesiobuccal cusp of 6
occludes with the distobuccal cusp of 6, as
shown in Fig. 2, N.
 2. Distal.The mesiobuccal cusp of 6
occludes with the mesiobuccal cusp of 6, as
shown in Fig. 2, L.

 The flush terminal plane also occurs when these cusps
are vertical ; the flush terminal plane can be used to
score “cusp to cusp,” distal of 6, because the plane is
more easily visualized and its position is determined
from a normal E relation

 Overbite - Overbite is scored as the vertical distance from the incisal
edge of the maxillary central incisor to the incisal edge of the mandibular
central incisor.
 Overjet - Overjet is scored as the horizontal distance from the labial
surface of the maxillary central incisor to the labial surface of the
mandibular central incisor in millimeters.The scores may be positive,
zero, or negative.

 Posterior cross-bite (osseous type) - Cross-bite may be dental,
functional, or osseous.Therefore, in order for posterior cross-bite to be
an indicator of the osseous relation, it must be differentiated from other
types of cross-bite.
 Dental cross-bite - usually involves a tipping of one tooth as a result of
space insufficiency.The condition is localized and does not affect the size
or shape of the basal bone.

 Function& cross-bite involves muscular adjustment to tooth
interferences.The teeth seem to be in normal arch alignment, but the
lower jaw will not close without shifting, thereby causing the functional
cross-bite.
 Osseous cross-bite involves a gross mesiolateral disharmony of the
craniofacial skeleton. All teeth seem to be in normal arch alignment.
When a single tooth is involved, it is usually the most posterior molar; the
premolars are in osseous cross-bite only when the molars are also in
cross-bite.

 Posterior open bite - defined as the lack of occlusal contact between
any opposing posterior teeth (posterior teeth include the deciduous
canines and molars, and the permanent canines, premolars, and molars)
with the jaws in “centric occlusion.”

 Tooth displacement.
NONMIXED DENTITIONS.The scoring of tooth displacement for the
nonmixed dentition includes two degrees of displacements:
1. 1.5 to 2.0 mm deviation or 35 to 45 degrees of rotation from normal
arch alignment (scored as 1 or single weight)
2. > 2 mm deviation or > 45 degrees of rotation from normal arch
alignment (scored as 2 or double weight).

 MIXED DENTITION.Tooth displacement in the mixed dentition can be
divided into two types, depending on the cause.
1. Tooth displacement not associated with space deficiency.
2. Tooth displacement associated with space deficiency.
 Midline relations.
1. Diastema
2. Jaw deviation.

 Calculating forms of the occlusal index
 In keeping with the concept of validity during time, an index of
occlusion should consider the stages of dental development.
 The OI incorporates separate weighting mechanisms for each
stage :
1. Deciduous dentition stage-dental ages I and II.
2. Mixed-dentition stage-dental ages III, IV, andV.
3. Permanent dentition stage-dental ageVI.

 The OI contains two divisions anal seven syndromes.
 Divisions I and II* (normal or distal molar relation)
 Syndrome A : Overjet (5) and open-bite (7).
 Syndrome B : Distal molar relation (2), overjet (5), overbite (8)) posterior cross-
bite (11 and 12)) midline diastema (IS), and midline deviation (17).
 Syndrome C : Congenitally missing incisors (10).
 Syndrome D : Potential tooth displacement (1) and tooth displacement (15).
 Syndrome E : Posterior open-bite (14).
 Division III (mesial molar relation)
 Syndrome F : Mesial molar relation (3), overjet (6), overbite (9), posterior cross-
bite (13), midline diastema (16)) and midline deviation (17).
 Syndrome G : Mixed-dentition analysis (1) and tooth displacement (15).

 If Divisions I and II was circled, the score is the score of the syndrome with the
highest score (either A, B, C, D, or E) plus one half of the total scores of the
remaining syndromes.
 If Division III was circled, the score is the score of the syndrome with the highest
score (either F or G) plus one half of the total score of the other syndrome

 Interpretation of the occlusal index (OI) scores
 After the judges had reranked the sixty sets of casts in the standard, they
were asked to classify the rankings subjectively.
 The subjective classification resulted in the following classes :
1. Good occlusions-No evidence of an occlusal disorder.
2. No treatment-Slight deviations in the occlusion, but no treatment
indicated at this time.
3. Minor treatment-Minor deviations in the occlusion which could be
remedied by simple treatment (that is, space regainers or removable
appliances).

4. Definite treatment-Major deviations in the occlusion which could be remedied by
major treatment (that is, treatment which would include banding of many teeth).
5.Worst occlusions-Major deviations in the occlusion which could be remedied by
major treatment; these occlusions were highly disfiguring to the patient and would
probably rank first in treatment priority.

 The primary objective of the assessment is to determine the prevalence
of malocclusion and dental irregularities and to estimate the treatment
needs of a population.
 The examination should not be made on subjects who are still in the
mixed dentition stage of development.
 Because of the complexity and length of the examination, criteria and
codes are specified for each box on the recording form.

 Terms such as dental irregularity, overlap, and crowding are subjective,
nonquantitative, even emotional terms which can represent a diversity of
clinical meaning.
 Adjectives such as mild, moderate, severe, significant, etc. are
descriptively helpful but still allow a wide range of interpretation.
 The proposed scoring method involves measuring the linear
displacement of the anatomic contact points of each mandibular
incisor from the adjacent tooth anatomic point.

 Measurements are obtained with a dial caliper calibrated to at least tenths
of a millimeter.
 The dial caliper is easier to read and is more precise than the vernier
caliper, where accuracy to 0.1 mm is important.
 The caliper points should be sharpened to a fine edge to permit access and
make accurate measurements possible.

 Each of the five measurements is obtained directly from the
mandibular cast rather than intraorally.
 Each of the five measurements represents a horizontal linear
distance between the vertical projection of the anatomic
contact points of adjacent teeth.

 In phase 1 of this study, seven orthodontists with varying backgrounds
and clinical experience evaluated the anterior irregularity present in fifty
casts selected to represent a wide range of crowding.
 Each cast was subjectively ranked on a scale ranging from 0 to 10, using
the following criteria:
 0 perfect alignment
 l-3 minimal irregularity
 4-6 moderate irregularity
 7-9 severe irregularity
 10 very severe irregularity

 The intent of the HLD index is to measure the degree of handicap caused by
the different components of malocclusion.
 Dr Harry L. Draker developed the Handicapping Labio-lingual Deviation index
(HLD) (Draker, 1960, 1967) which was one of the first indices used in the United
States to identify those with handicapping malocclusions (Theis et al., 2005).
 The HLD selects deviations from ideal and these are scored and weighted.
 Modified by some states to determine and prioritize eligibility for the state-
funded orthodontic treatment.

 The original cut-off point of 13 selected for the HLD index.
 The Maryland’s version of HLD modified the HLD’s original scoring
formula for overjet and overbite.The Maryland’s index, the HLD (Md),
changed the cut-off from 13 to 15 points and modified the Draker’s
scoring formula by subtracting 2 mm from overjet and 3 mm from
overbite measurements (Code of Maryland Regulations, 1982; Cooke et
al., 2010).
 The state ofWashington HLD modification has five qualifying conditions
and the cut-off point has changed to 30 (Theis et al., 2005).

 The original form of the HLD index is not a reliable index to assess the orthodontic
treatment need as it does not record missing, impacted teeth, spacing between
teeth, and transverse discrepancies such as midline deviations and crossbites.

 The HLD index was modified in the state of California, the HLD (CalMod) index
(Parker, 1998), and used the cut-off point of 26.The HLD (CalMod) has been created
because of the settlements originating from two lawsuits against the state of
California.
 As a result of these lawsuits, two qualifying exceptions that cause tissue damage were
added to the original HLD index, namely the deep impinging bites and crossbites of
individual anterior teeth with tissue destruction (Parker, 1998).

 In addition, overjets greater than 9 mm and reverse overjets more
than 3.5 mm were added as additional qualifying exceptions.
 The ectopic eruption and unilateral posterior crossbite were also added
as weighted factors (Parker, 1998).
 Table shows the components of the HLD (CalMod) index that is currently
used in the state of California.

 Conditions 1 to 6 are the qualifying conditions and if present further
scoring is not needed

 Otherwise, the sum of other conditions (7-14) must be 26 or above to
be considered as a handicapping malocclusion

 If both anterior crowding and ectopic eruption are present in the anterior
portion of the mouth, the most severe condition will be scored, not both
conditions.

 The HLD (calmod) index records twelve factors and occlusal traits to produce the final
score.These factors are:
1. Overjet
2. Overbite
3. Open bite
4. Cleft lip-palate
5. Anterior crowding
6. Mandibular protrusion
7. Labio-lingual spread
8. Deep impinging overbite
9. Severe traumatic deviations
10. Crossbite of individual anterior teeth
11. Ectopic eruption of anterior teeth
12. Posterior unilateral crossbite.

(SMBI 1966; Linder Aronson, 1974, 1976)

 The DHC of IOTN is similar to an index used by the Swedish Medical
Health Board ‘the Swedish Medical Board Index (SMBI) .
 The original form of this Swedish index was developed having 4
categories of need (grade 1 to 4).
 Later on, Linder-Aronson and co-workers (1976) revised the index and
added a fifth category, the grade zero, describing subjects with no
need for treatment .

 This revised SMBI index is very similar to the DHC of IOTN; however, the DHC
in IOTN is graded from 1 to 5.
 The SMBI calls for the subjective views and patient's wishes to be considered
when deciding on the treatment need (Mockbil & Huggare, 2009).
 It has been suggested the arbitrary grading system in the SMBI leads to low
level of reproducibility, particularly when the index is used by non-
professionals .

Grade
4 Very urgent Need aesthetically and/or functionally handicapping anomalies,
such as deft lip and palate, extreme post-normal or pre-normal
occlusion, retained upper incisors, extensive aplasia.
3 Urgent need Pre-normal forced bite, deep bite with gingival irritation not
only on papilla incisiva, large overjet with lower lip behind upper
centrals, extremely open bite, crossbite causing transverse
forced bite, scissors bite interfering with articulation, severe
frontal crowding or spacing, retained canines, aesthetically
and/or functionally disturbing rotations.

Grade
2 Moderate need Aesthetically and/or functionally disturbing proclined or
retroclined incisors, deep bite with gingival contact but without
gingival irritation, severe crowding or spacing, infraocclusion of
deciduous molars and permanent teeth, moderate frontal
rotations.
1 Little need Mild deviations from normal (ideal) occlusion, such as
prenormal occlusion with little negative overjet, post-normal
occlusion without other anomalies, deep bite without gingival
contact, open bite with little frontal opening, crossbite without a
forced bite, mild crowding or spacing, mild rotations of only little
aesthetic and/or functional significance.
0 No need Normal (ideal) occlusion without deviations

 The DentalAesthetic Index (DAI) (Cons et al., 1986) looks into the
aesthetic aspects of occlusion.
 The DAI links clinical and aesthetic components, mathematically, to
produce a single score which reflects the malocclusion severity.
 By using cut-off points, index was subsequently used to determine the
need for orthodontic treatment.

 The DAI is based on a social acceptability scale of occlusal conditions
(Jenny et al, 1980). Dr. NahamC. Cons, a public health dentist, and co-
workers used the opinions of the lay public to find out what constituted
unacceptable dental arrangements from the aesthetic standpoint (Cons
et al., 1986)
 The DAI highlights the importance of physical attractiveness and by
considering societally defined norms for dental appearance, it recognizes
conditions that are potentially psycho-socially handicapping.

 The DAI used a regression equation that called for the measured
components of DAI to be multiplied by their regression coefficients
(weights), addition of their products and a constant number (n=13) to the
total.The resulting sum was the DAI score.
 The DAI was designed to be used in permanent dentition and a modified
version of the index has been suggested for the mixed dentition (Johnson
et al, 2000).

 An advantage of the DAI is the use of threshold scores (i.e. 31 or higher)
to equate with the need for orthodontic services.
 This threshold limits changes based on available resources and funding.

 The lack of assessment of occlusal anomalies such as buccal crossbite,
impacted teeth, centre-line discrepancy, and deep overbite weakens the
index .
 The DAI also does not account for missing molars.
 Although deviations for crowding and spacing components are scored as
present or absent, there is no distinction between varying degrees of
arch length discrepancy.
 These limitations should be considered when using the DAI for
epidemiological studies or in studies assessing relationship between
malocclusion and other variables.

 The index of OrthodonticTreatment Need index has been a reliable
epidemiological tool, which benefits local health services in planning their
budget, and improve focus of services by inducing greater uniformity and
standardization in the assessment of Orthodontic treatment need
 The Index Of OrthodonticTreatment Need5The Index of OrthodonticTreatment
Need was developed in UK by Brook & Shaw in 1989.
 It was introduced as Index of Orthodontic Treatment Priority and later renamed
as ‘IOTN’.

 It is a clinical index which prioritizes and classifies malocclusion
according to treatment needs ultimately to compare populations.
 IOTN index is a modification of the index used by the Swedish Dental
Health Board which was used to record the need for Orthodontic
treatment on dental health and functional grounds.

 The IOTN index is one of the commonly used quantitative types of
Occlusal indices that assess the Orthodontic treatment need among
children and adults.
 The IOTN has two separate components;
a) a clinical component called the Dental Health Component (DHC)
b) an Aesthetic Component (AC).
 DHC and AC are two separate components and are not combined
together.

 There are five grades, grade 1 representing little or no need for treatment and
grade 5 representing great need of treatment (Table 1)
 Most of the traits are recorded using a millimeter rule, modified to incorporate a
device for angular measurements.
 Crowding was recorded by measuring the largest displacement between teeth in
the arches.

 For this component the SCAN Index (Standardized Continuum of Aesthetic Need) was
utilized (Evans and Shaw, 1987).
 This scale was constructed using dental photographs of 1000, 12-year-olds collected
during a large multi-disciplinary survey.
 The Aesthetic component measures aesthetic impairment and justifies treatment on social
– psychological grounds.
 Six non-dental judges rated these photographs on a visual analogue scale, and at equal
intervals along the judged range, representative photographs were chosen giving a 10-
point scale from 0.5 (attractive dental appearance) to 5.0 (unattractive dental
appearance)

 A rating is allocated for overall dental attractiveness rather than specific
similarities to the photographs.The final value reflects the treatment
need on the grounds of aesthetic impairment and by implication of the
social psychological need for orthodontic treatment

Grade Treatment Need
Grade 5 (Need treatment) 5•i Impeded eruption of teeth (except for third molars) due
to crowding, displacement, the presence of supernumerary
teeth, retained deciduous teeth and any pathological cause.
5•h Extensive hypodontia with restorative implications .
(more than 1 tooth missing in any quadrant)
5•a Increased overjet greater than 9 mm.
5•m Reverse overjet greater than 3•5 mm with reported
masticatory and speech difficulties.
5•p Defects of cleft lip and palate and other craniofacial
anomalies.
5•s Submerged deciduous teeth.

Grade Treatment
Need
Grade 4 (Need
treatment)
4•h Less extensive hypodontia requiring pre-restorative
orthodontics or orthodontic space closure to obviate the need for a
prosthesis.
4•a Increased overjet greater than 6 mm, but less than or equal to
9 mm.
4•b Reverse overjet greater than 3•5 mm with no masticatory or
speech difficulties.
4•m Reverse overjet greater than 1 mm but less than 3•5 mm with
recorded masticatory and speech difficulties.
4•c Anterior or posterior crossbites with greater than 2 mm
discrepancy between retruded contact position and intercuspal
position.
4•l Posterior lingual crossbite with no functional occlusal contact in
one or both buccal segments.
4•d Severe contact point displacements greater than 4 mm.
4•e Extreme lateral or anterior open bites greater than 4 mm.
4•f Increased and complete overbite with gingival or palatal
trauma.
4•t Partially erupted teeth, tipped and impacted against adjacent
teeth.
4•x Presence of supernumerary teeth.

Grade Treatment Need
Grade 3 (Borderline need) 3•a Increased overjet greater than 3•5 mm, but less than or
equal to 6 mm with incompetent lips.
3•b Reverse overjet greater than 1 mm, but less than or
equal to 3•5 mm.
3•c Anterior or posterior crossbites with greater than 1 mm,
but less than or equal to 2 mm discrepancy between
retruded contact position and intercuspal position.
3•d Contact point displacements greater than 2 mm, but less
than or equal to 4 mm.
3•e Lateral or anterior open bite greater than 2 mm, but less
than or equal to 4 mm.
3•f Deep overbite complete on gingival or palatal tissues, but
no trauma.

Grade Treatment
Need
Grade 2 (Slight) 2•a Increased overjet greater than 3•5 mm, but less than or equal to 6 mm
with competent lips.
2•b Reverse overjet greater than 0 mm but less than or equal to 1 mm.
2•cAnt. or post. crossbite with less than or equal to 1 mm discrepancy
between retruded contact position and intercuspal position.
2•dContact point displacements more than 1 mm but less than or equal to
2 mm.
2•eAnterior or posterior open bite more than 1 mm but less than or equal
to 2 mm.
2•f Increased overbite greater than or equal to 3•5 mm without gingival
contact.
2•g Pre- or post-normal occlusions with no other anomalies (includes up
to half a unit discrepancy).
Grade 1 (None) 1• Extremely minor malocclusions including contact point
displacements less than 1 mm.

1. Missing teeth (including aplasia, displaced & impacted teeth)
2. Overjets (including reverse sagittal overjets)
3. Crossbites
4. Displacements
5. Overbites
 Pneumonic acronym: MOCDO
 The hierarchical scale has two components
1. The dentition is assessed systematically, thus ensuring that all relevant
occlusion anomalies are recorded.
2. If two or more occlusal anomalies are of the same DHC grade, the most
severe one is scored.

1. IOTN is a clinical index to assess Orthodontic treatment need.
2. The index can be used either directly on the patient or on the plaster
models.
3. The validity and reliability of the IOTN have been verified.
4. IOTN is one of the most commonly used occlusal indices to assess the
Orthodontic treatment need among children and adults.
5. The index defines specific, distinct categories of treatment need, whist
including a measure of function .

6 IOTN has gained international recognition as a method of objectively assessing
treatment need.
7 The IOTN data gives support for early Orthodontic treatment need.
8 IOTN is objective, synthetic and allows for comparison between different
population groups.
9 IOTN is proved to be an easy-to-use and reliable method to describe the need for
Orthodontic treatment need.

10 The DHC of IOTN helps in determining manpower requirements for
planningOrthodontic treatment need.
11 The Aesthetic component of IOTN reflects the social and psychological
need for Orthodontic treatment need.

 1. Sometimes there might be a discrepancy between the Dental Health
Component and Aesthetic Component grades of IOTN index.
 2.The Aesthetic Component of IOTN assesses the aesthetic aspects of
malocclusion only in the frontal view and highlights the subjective
nature of it.

 The modified IOTN is a two – grade scale,
 Grade 1- No Need
 Grade 2- Definite Need
 Instead of five grade scale with 30 sub categories, the modified
IOTN is based on idea that the IOTN is not an index to measure
the complexity; and therefore, there is no benefit in recording the
occlusal anomaly that placed the child in treatment need category.

 The modified IOTN simplifies identifying people in need of treatment
and improves the reliability and validity of the index.
 By using the modified IOTN, every case with IOTN DHC ≥ 4 and / or IOTN
AC ≥ 8 is classified as being in need of treatment.
 Since its introduction, few epidemiological studies used the modified
IOTN; the index has been simplified to two categories:
1. Definite Need forTreatment
2. No Definite Need forTreatment

 The spectrum of malocclusion ranges from near ideal to markedly
anomalous and so the justification for treatment for an individual will
vary.
 The actual receipt of treatment may also be modified by patient
demands.
 The point at which the potential risks of treatment outweigh the
potential benefits is a matter of contention and must be judged for
patients on an individual basis.

 Most research suggests that patients seek treatment principally for aesthetic
improvements and that the principle benefits perceived by patients post-
treatment are related to aesthetics.
 Psycho-social Enhancement - . Many younger patients are brought for
treatment by parents who may be seeking the treatment for reasons other than
the child’s malocclusion
 Functional Improvement and Promotion of Better Oral Health- Correction of
defects in speech or mastication and enhancement of dental and oral health
could also justify orthodontic treatment

 Cleft Lip and Palate - The immediate impact of an oro-facial cleft is the
dentofacial deformity with later affects on speech, hearing, mastication,
and dentofacial appearance.
 Posterior Crossbite - In conjunction with erosion, a crossbite with an
associated slide to intercuspal position can cause considerable tooth
surface loss.
There is a demonstrable increase inTMD where the slide on closure to
intercuspal position is 4 mm or greater, or in the presence of unilateral
lingual crossbite (McNamara, 1995).

Increased overjet (greater than 6 mm) –
 Increased trauma to the upper incisors and especially in the presence of
incompetent
 Accentuated periodontal destruction associated with overjets greater
than 8
 Oral hygiene may be poorer with increased overjet

Reverse Overjet –
 Certain speech articulation defects have been noted more commonly in
Finnish dental students with Class III incisor or molar relationship than
with normal occlusion (Laine, 1987, 1992).
 Class III malocclusion was correlated with symptoms of TMD in males,
andWisth (1984) found in a retrospective sample that a treated group of
class III patients had fewerTMD symptoms than an untreated control
group

 Impeded Eruption or Impaction ofTeeth - Impeded teeth may cause
follicular cyst formation and resorption of adjacent teeth.
 Anterior Open Bite -This trait has been associated withTMD
(McNamara, 1995), but has a more obvious effect on the reduced
efficiency of biting in the incisor region and certain poor sound.
 Hypodontia -Visible missing anterior teeth are considered to be among
the most unattractive occlusal traits.

 Deep Overbite (GreaterThan 6 mm) - Direct tissue trauma
 Contact Point Displacement - It is the commonest malocclusal trait.
Dental crowding associate with increased periodontal
 Spacing - Dental spacing has no dental health significance, other than it
is associated with a lower incidence of caries (Helm and Petersen, 1989).

 Although IOTN and PAR are both reliable and valid they have some
important limitations:
 1.The two indices have been developed and validated to assess treatment
entry and exits as separate phenomena, when they are clearly part of the
same clinical process.
 2.Treatment categorizations using the Dental Health Component and the
Aesthetic Component can be contradictory, with one component suggesting
treatment and the other suggesting no treatment.
 3.The hierarchical structure of Dental Health Component requires a separate
protocol when only study models are available.

 4.The IOTN or PAR indices have been validated against UK dental
opinion (Richmond et al., 1992, 1995) and thus may not be
representative of professional opinions in other countries.
 5.The PAR index, has been criticized for undue leniency of residual
extraction spacing, unfavourable incisor inclinations, and rotations.
 6. PAR takes no account of periodontal destruction, decalcification, root
resorption, dynamic occlusion, and facial aesthetics.

 Objectives -The objectives of this study were to propose orthodontic
indices to assess treatment need, complexity, treatment improvement,
and outcome based on international professional opinion, intended for
use in the context of specialist practice.
 Such indices could provide the means to compare treatment thresholds
in different countries and serve as a basis for quality assurance standards
in orthodontics.

 Methods - Professional perceptions of treatment need and treatment
outcome were solicited by asking an international panel of 97
orthodontists from nine countries to judge a diverse sample of study
casts.
 The study cast material consisted of 240 dental casts for assessment of
treatment need and 98 paired pretreatment and post-treatment cases
for assessment of treatment outcome.

 The occlusal traits scored included:
1. Upper and lower labial segment alignment;
2. Anterior vertical relationship, centreline, impacted teeth, upper and lower
buccal segment alignment (left and right added together), buccal segment
antero-posterior relationship (left and right added together), buccal
segment vertical relationship (left and right added together), crossbite,
missing teeth for any reason (excluding 3rd molar);
3. Aesthetic assessment based on IOTN aesthetic component, overjet in mm
(centred at 3 mm), reverse overjet in mm, upper and lower incisor
inclination relative to the occlusal plane, overall upper arch crowding/
spacing, overall lower arch crowding/spacing, lip competency.

 Results -The new index is comprised of an assessment of dental
aesthetics, the presence of crossbite, analysis of upper arch crowding (or
the presence of impacted teeth in either arch), buccal segment antero-
posterior inter-digitation, and the anterior vertical relationship.The
scoring protocols are described in the appendix

Determining Treatment Need and Outcome AcceptabilityThreshold Values
 All pretreatment score values greater than 43, would be considered in need
of treatment.
 Post-treatment scores of less than 31 signify acceptable end occlusion.
 These cut-off values were chosen to optimize the specificity and sensitivity of
the index (using aggregate practitioner opinion as the gold standard).
 The specificity and sensitivity of the index varies depending on the cut-off
values chosen.
 The performance of the index at the optimum cut-off values for assessments
of treatment need and outcome acceptability is shown inTable 2.

 Practical Use of the Index to AssessTreatment Need
The five occlusal trait scores are multiplied by their respective weightings
and summed (Table 3). If the summary score is greater than 43,
treatment is indicated.
 Practical Use of the Index to AssessTreatment Outcome Acceptability
To assess treatment outcome, apply the index scoring method to the
post-treatment models only. If the summary score is less than 31 the
outcome is acceptable.

 Practical Use of the Index to AssessTreatment Complexity -To assess
treatment complexity as a 5-point scale it is probably justifiable to use
the cut points for the 20 percentile intervals, using the ranges given in
Table 4 from the pretreatment models.

 Important occlusal traits, such as cleft palate, overjet, reverse overjet, and
hypodontia, are not measured directly by the index, and it is easy for the unwary
to think that a serious omission in the index structure has occurred.
 Disparate occlusal traits such as cleft lip, overjet, hypodontia, etc., have a large
impact on the anterior aesthetics of the malocclusion, all of which can be
efficiently reflected by the aesthetic component score.
 The ICON has relatively lower predictive accuracy for the treatment outcome
than for treatment need judgements.This is due to the much lower level of inter-
examiner agreement in decisions of treatment acceptability

 The practical application of the index has been kept as simple as possible and it is expected
that the index will prove reliable and easy to apply, to study models or clinically.
 The accuracy of the index to reflect professional opinion for a diverse sample of cases was
estimated at 84 per cent for decisions of treatment need and 68 per cent for treatment
outcomes.The method is heavily weighted by aesthetics.

 The concept is to assign a score to various occlusal traits which make up a
malocclusion. The individual scores are summed to obtain an overall
total, representing the degree a case deviates from normal alignment and
occlusion.
 The score of zero would indicate good alignment and higher scores
(rarely beyond 50) indicating increased levels of irregularity.
 The overall score is recorded on the pre- and post-treatment dental casts.
 The difference between these scores represents the degree of
improvement as a result of orthodontic intervention and active
treatment.

1. Upper right segment
2. Upper anterior segment
3. Upper left segment
4. Lower right segment
5. Lower anterior segment
6. Lower left segment
7. Right buccal occlusion
8. Overjet
9. Overbite
10. Centreline
11. Left buccal occlusion

Buccal and anterior segments
 The dental arch is divided into three recording segments, left buccal, right buccal and
anterior. Scores are recorded for both upper and lower arches.
Buccal segments.
 The recording zone is from the mesial anatomical contact point of the first permanent
molar to the distal anatomical contact point of the canine.
Anterior segment.
 The recording zone is from the mesial anatomical contact point of the canine on one side to
the mesial anatomical contact point of the canine on the opposite side.
 The occlusal features recorded are crowding, spacing, and impacted teeth.

 Displacements are recorded as the shortest distance between contact points of
adjacent teeth parallel to the occlusal plane.The greater the displacement the greater
the PAR score.
 The displacements between first, second, and third molars are not recorded as these
contacts are so broad and are extremely variable within the normal range.
 An impacted tooth is recorded when the space for this tooth is less than or equal to 4
mm. Impacted canines are recorded in the anterior segment.
 Scores for the displacements and impactions are added to give an overall score for
each recording zone.

Buccal occlusion
 The buccal occlusion is recorded for both left and right sides. The fit of the teeth is scored
with respect to the three planes of space.The recording zone is from the canine to the last
molar, either first, second, or third. All discrepancies are recorded when the teeth are in
occlusion.

Overjet
 Positive overjet as well as teeth in cross-bite are recorded .
 The recording zone is from the left to right lateral incisors.
 The most prominent aspect of any one incisor is recorded.
 It is not uncommon to see two upper laterals in cross-bite as well as an
increased overjet on the central incisors. In this situation if the overjet
were 4 mm, the score would be 3 for the cross-bite and 1 for the positive
overjet (4 in total).

Overbite
 Records the vertical overlap or open bite of the anterior teeth. Overbite is
recorded in relation to the coverage of the lower incisors or the degree of open
bite.The recording zone includes the lateral incisors. The tooth with the
greatest overlap is recorded.

Centreline
 Records the centreline discrepancy in relation to the lower central
incisors .
 If a lower central incisor has been extracted the measurement is not
recorded.

 A ruler has been designed to make measurement easier .
 Cross-bites including the canines are recorded in the anterior segment.
 Score Discrepancy Open bite 0 I 2 3 4 Overbite 0 1 2 3 No open bite Open bite
less than and equal to 1 mm Open bite 1.1-2 mm Open bite 2.1-3 mm Open
bite greater than or equal to 4 mm Less than or equal to one third coverage of
the lower incisor Greater than one-third, but less than two-thirds coverage of
the lower incisor Greater than two-thirds coverage of the lower incisor
Greater than or equal to full tooth coverage at UCSF Library on September
12,

 The ruler is shown recording the
displacement between the mesial
contact points of the incisors.The line
designated 2 is slightly short of the
contact points; therefore, the next
longer line would be used and the
contact point score between the
central incisors would be 3.
 Figure 5 shows the ruler being used
to record the overjet and in this case
would score 2.

 In general, the PAR Index indicated excellent intra- and inter-examiner
agreement.
 Lower levels of agreement were achieved for some of the individual PAR
components, particularly the upper left and right buccal segments compared
to the corresponding segments in the lower arch.
 This may be due to the increased size and the differing morphology of the
maxillary teeth, which result in broad contact points and make accurate
displacement measurements more difficult than in the lower arch.
 The use of the ruler with a brief summary contained within, eliminates cross-
references to notes of complicated criteria.

1. The Development of the Index of Complexity, Outcome and Need (ICON)
Article in Journal of Orthodontics · July 2000
2. The relationship between occlusion and periodontal status DONALD R. POULTON,
D.D.S.,” AND SANFORD A. AARONSON, D.D.S.“” San Francisco and Alameda, Calif.
3. European Orthodontic SocietyThe development of an index of orthodontic treatment
priority Peter H. Brook* and William C. Shaw"
4. Bulletin of theWorld Health Organization, 57 (6): 955-961 (1979) Basic method for
recording occlusal traitsV. BEZROUKOV,1 T. J. FREER,2 S. HELM,3 H. KALAMKAROV,4 J.
SARDO INFIRRI,5 B. SOLOW6
5. The occEusal index: A system for id&if ying and scoring occlusal disorders Chester J.
Summers, D.D.S., MS., Dr.P.H. Ann Arbor, Mich.
6. European Journal of OnHodonlks 14 (1992) 125-139 1992 European Orthodontic Society
The development of the PAR Index (Peer Assessment Rating): reliability and validity S.
Richmond, W. C. Shaw, K. D. O'Brien, I. B. Buchanan, R. Jones, C. D. Stephens,* C.T.
Roberts, and M. Andrews

7 ASSESSMENT OF MALOCCLUSION IN POPULATION GROUPS Lawrence E.Van Kirk, Jr.,
D.D.S., M.P.H., and Elliott H. Penncll, F.A.P.H.A.
8 PREVALENCE OF MALOCCLUSION IN CHILDREN AGED 14TO 18YEARS M~URY
MASSLER, D.D.S., MS.,*
9 An Overview of Selected OrthodonticTreatment Need Indices1 Ali Borzabadi-Farahani
Craniofacial Orthodontics, Children’s Hospital Los Angeles, University of Southern
California, Los Angeles, CA USA
10 Assessment of Malocclusion Severity Levels and OrthodonticTreatment Needs using the
Dental Aesthetic Index (DAI): A Retrospective Study S. Goyal1,*, S. Goyal2 , A.
Muhigana1 1Dental Department, King Faisal Hospital, Kigali, Rwanda 2Polyclinique La
Medicale, Kigali, Rwanda
11 : https://www.researchgate.net/publication/284274729 A Review of Orthodontic Indices
Article in Orthodontic Journal of Nepal · November 2015 DOI: 10.3126/ojn.v4i2.13898

12 From: Department of Orthodontics, Royal Dental College, Copenhagen,
Denmark. A METHOD FOR EPIDEMIOLOGICAL REGISTRATIONOF
MALOCCLUSION by A. I~J~RK AA. KRERS B. Sotow
13 The Irregularity Index: A quantitative score of mandibular anterior aZignment
Robert M. little, D.D.S., M.S.D., Ph.D.* Seattle,Wash.

Epidemiological indices - Dr. Shubham Narnoli

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