Classification of malocclusion  

Purposes

-Diagnosis and Treatment planing

-Describing and documenting a patient’s occlusion and communications.

-Allow the prevalence of a malocclusion within a population to be recorded,

-Aid in the assessment of need, difficulty, and success of orthodontic treatment

Malocclusion Classification  

Quantitative

ََََQualitative

Normal Occlusion

Two different approaches :

- Feature of a malocclusion is given a score and the summed total is then recorded (e.g. the PAR Index).

Descriptive:

- The worst feature of a malocclusion is recorded (e.g. the Index of Orthodontic Treatment Need)

e.g. - Angle in 1899, The British Standards Institute BSI (1983

Drawback:

Continuous variable so that no clear cut-off points

Does not provide any indication of the difficulty of treatment.

The occlusion when upper and lower molars are in relationship such that the mesiobuccal cusp of upper molar occluded with mesiobuccal groove of lower molar and teeth are all arranged in a smoothly curving line, Angle (1899) .

Houston et al, (1992) defined normal occlusion as an occlusion within accepted definition of the ideal and which caused no functional or aesthetic problems.

Commonly used classifications and indices 

Summers occlusal index 

Angle’s classification 

The first permanent molars erupted into a constant position within the facial skeleton.

Assess the anteroposterior relationship of the arches.

Loss of the first permanent molars

Particularly for research purposes.

The success of treatment.

The index scores nine defined parameters including :

Objectives

molar relationship, overbite, overjet, posterior crossbite, posterior open bite, tooth displacement, midline relation, maxillary median diastema, and absent upper incisors.

British Standards Institute classification 

Drawbacks:

This is based upon incisor relationship

The most widely used descriptive classification.

as with any descriptive analysis it is difficult to classify borderline cases.

Classification of Malocclusion  

by Sami Alshahrani

Introduction

Definitions

Need of Classification

Different Classification Systems

Andrews’ six keys

Index of Orthodontic Treatment Need (IOTN) 

Thanks

Determine the likely impact of a malocclusion on an individual’s dental health and psychosocial well-being.

It comprises two elements:

References:

2.Aesthetic component

1.Dental health component

A set of ten standard photographs, which are also graded

from score 1, the most aesthetically pleasing,

to score 10, the least aesthetically pleasing.

The scores are categorized according to need for treatment as follows: 

The single worst feature of a malocclusion is noted and categorized reflecting need for treatment

*dental health component Alone is more Widely used.

An Introduction to Orthodontics 4th Edition by Laura Mitchell.

Hassan R, Rahimah AK. Occlusion, malocclusion and method of measurements-an overview. Archives of orofacial sciences. 2007;2:3-9.

score 1 or 2 — none

score 3 or 4 — slight

score 5, 6, or 7 — moderate/borderline

score 8, 9, or 10 — definite

Grade 1 — no need

Grade 2 — little need

Grade 3 — moderate need

Grade 4 — great need

Grade 5 — very great need 

Andrews’ six keys

Index of Complexity, Outcome and Need (ICON)

These six keys , not a method classification.

Serve as a goal, Occasionally at the end of treatment it is not possible to achieve a good Class I occlusion in such cases it is helpful to look at each of these features in order to evaluate.

Incorporates features of both (IOTN) and (PAR).

Peer Assessment Rating(PAR) 

The total sum gives a pretreatment score, which is said to reflect the need for, and likely complexity of, the treatment required.

Correct molar relationship

Correct crown angulation: all tooth crowns are angulated mesially

Correct crown inclination: incisors are inclined towards the labial surface.

No rotations

No spaces

Flat occlusal plane

Primarily to measure the success of treatment.

The difference between the PAR parameters scores can be calculated, before and at the end of treatment.

Gives an indication of the severity of a malocclusion.