Epidemiology of Malocclusion

1. EPIDEMIOLOGY OF
MALOCCLUSION
DR CHANDRIKA KATTI
Reader, Dept Of Orthodontics.
Navodaya Dental College,
Raichur.

2. INTRODUCTION
 Many organized population surveys have been
carried out in different parts of the world with the
objective of estimating prevalence of malocclusion
& orthodontic treatment needs.
 Prevalence of malocclusion is higher in developed
countries as compared to developing & under
developed countries.

3.  No of indexes have been conducted to determine
prevalence of malocclusion.
 Prevalence of malocclusion in chinese population is
67.82%
 In Nigeria its 84.0%=Angles class I malocclusion,
 Class II 1.7%
 Indian children 19.6% in madras,
 Delhi 90%
 Indians exhibit low incidence
 Class III in India is < compared to USA

4. MEASUREMENT OF MALOCCLUSION
 Jamison & McMillan proposed list of requirements
for ideal orthodontic index :
 The index should be simple, accurate, reliable &
reproducible.
 The index should be objective in nature & yield
quantitative data which be analyzed by current
statistical methods
 The index must be so designed as to differentiate
between handicapping & non-handicapping
malocclusion

5. MEASUREMENT OF MALOCCLUSION
 The examination required must be one that can be
performed quickly by examiners even without
special instruction in orthodontic diagnosis.
 The index should lend itself to modification for the
collection of epidemiological data, regarding
malocclusion other than prevalence, incidence,
severity.
 The index should be usable either on patients or on
study models
 The index should measure the degree of handicap,
if any & avoid classifying malocclusion.

6.  Measurement of malocclusion :
 Handicapping Labio-Lingual Deviation Index(HLD
index)
 Was devised by Harry L.Draker in 1960,
 Was proposed to select subjects with severe or
handicapping malocclusion and dentofacial
anomalies.
 Its applicable only in permanent dentition,

7. METHOD
 3 planes commonly used for orthodontics
orientation i.e. the sagittal, Frankfort,& the orbital
are basis for HLD index measurement.
 The main intention of this index is to measure the
degree of handicap caused by the components of
the index
 Its based on 7 components.
 All are measured with Boley Gauge scaled in
millimeters