Index has been defined as a numerical value
describing the relative status of a population
on a graded scale with defined upper and
lower limits, which is defined to facilitate and
permit comparison with other populations
classified under the same criteria and method.
In the ORTHODONTIC context an index is
used to describe a rating system that assingns
a numeric score to a person’s occlusion.
In this era of evidence based Dentistry,
Quantitative measurements are necessary, so as to
quantiate the treatment and compare the results
with some standard care.
Comparing the quality of Orthodontic treatment is
For this reason several valid and reliable Indices
have been developed to
1. Asses the treatment need
2. Compare the treatment Outocome
Indices have been used for the purpose of
Epidemiology , research and for categorizing
patients according to treatment need.
Five distinct Type of Indices have been defined,
each for a distinct purpose.
1. Diagnostic Indices
2. Epidemiologic Indices
3. Treatment need indices
4. Treatment outcome Indices
5. Treatment Complexity Indices
Proposed by BROOK and SHAW in 1989.
Asses orthodontic treatment need from
anatomic and aesthetic point of view.
It consists of Two independent components
1. Dental Health component
2. Aesthetic Component
This is categorized in 5 grades ranging from 1
(no treatment need ) to 5 (great need).
Based on evaluation of 5 occlusal traits
1. Missing teeth
4. Contact point diplacment
Grade 1 (no treatment need)
Extremely minor malocclusion including contact point displacement.
Grade 2 (Mild/little need)
2.a) Increased overjet greater than 3.5mm 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.c) anterior or posterior crossbite with less than or equal to 1 mm
2.d) anterior or posterior open bite of 1 mm but less than or equal to 2 mm.
2.e) increased overbite greater than or equal to 3.5 mm but with no gingival
2.f) contact point diplacment equal to 1 mm but less than or equal to 2 mm.
2.g) pre normal or post normal occlusion with no other abnormalities.
Grade 3(moderate/borderline need)
3.a) Same as grade 2 with incompetent lips
3.b) reverse overjet greater than 1 mm but less than or equal to 3.5
3.c) anterior or posterior crossbite with greater than 1mm discrepancy
but less than 2 mm
3.d) contact point displacement 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 on gingival and palatal tissues but no trauma
Grade 4(severe/need treatment)
4.a) Less extensive hypodontia (less than or equal to one tooth per
4.b) increased over jet greater than 6 mm but less than or equal to 9 mm
4.c) reverse over jet greater than 3.5 mm with no speech or masticatory
4.d) anterior or posterior crossbite with greater than 2 mm discrepancy.
4.e) posterior lingual crossbite with no functional occlusal contact in one
or both buccal segments.
4.f) severe contact point displacement greater than 4 mm.
4.g) extreme openbite greater than 4mm
4.h) partially erupted, impacted tipped teeth.
4.i) increased overbite with palatal trauma.
4.j) presence of supernumerary teeth.
Grade 5(extreme/need treatment)
5.a) Impacted eruption of teeth(except third molars) due to crowding,
displacement, the presence of supernumerary, retained deciduous
and pathological causes
5.b) extensive hypodontia
5.c) increased overjet greater than 9 mm
5.d) reverse overjet greater than 3.5 mm with reported masticatory
and speech problems
5.e) submerged deciduous teeth
10 front viewing photographs illustrating
varying degree of Occlusion (serves as a scale)
attractive and unattractive occlusion or casts
viewed from front.
The rating is based on matching the dental
appearance of the patient with one of the
photographs by an orthodontist or non
No profile views are included
Photographs are arranged from number 1(most
attractive) to number 10(most non attractive)
The patient score is based on matching his/her
photograph with that of reference
Rating is allocated for overall dental
attractiveness rather than specific morphologic
similarities to the photographs.
Modifications were introduced in 1993
The Dental health component and aesthetic
component were modified to improve the
reliability of these components.
In the dental health component DHC, the 5
grades were reduced to 3
Grade 1,2….. No treatment need
Grade 3……. Borderline
Grade 4,5….. Treatment need
In the Aesthetic component AC the 10 point
scale was reduced to 3 point scale
1. Photographs 1-4…. No treatment need
2. Photograph 5-7….. Borderline need
3. Photograph 8-10…. Definite need
These modifications were accepted and are
used in British standards for Orthodontic
The use of indices in orthodontics allows more
uniform interpretation and application for
criteria for treatment need and changes.
Still there is a need of a development of index
which can be universally accepted in terms of
reliability and validity.
There is a need to improve diagnostic criteria
and develop a common approach for assessing