Classification Of Maloccuulsion Flashcards
What is malocclusion?
An appreciable deviation from the ideal occlusion that can be consider aesthetically or functionally unsatisfactory
List some facts about malocclusions.
Ideal occlusion is rare
Malocclusion is not a disease state but is regarded as a deviation form the normal
Not all malocclusions require treatment
Why do we treat malocclusions?
Dentofacial aesthetics
Dental health
Functional
To facilitate restorative treatment
What % of people have normal occlusion?
35%
What % of people have malocclusion?
65%
What % of people have Class I incisors?
50%
What % of people have Class II Div 1 incisors?
35-40%
What % of people have Class II Div 2 incisors?
10%
What % of people have Class III incisors?
3-5%
Why do we need an orthodontic diagnosis?
Help give a description of the occlusion
To help with treatment planning
Epidemiology and prioritising treatment needed
What are the features of malocclusion?
Malposition of the teeth (arch alignment)- crowding, rotations, unerupted/absent teeth
Mal relationship of the arches- anteroposterior, transverse, vertical
What are you looking for in the extra-oral examination in orthodontics?
Jaw relationship
In antero-posterior jaw relationship examination what are you looking for?
You are seeing if the mandible is more or less protrusive than the maxilla
In a vertical jaw relationship examination what are you looking for?
Is the lower part of the face too long or too short
In a transverse jaw relationship examination what are you looking for?
Is the face symmetrical if viewed from the front
What is an overjet?
Horizontal measurement between the upper and lower incisors (anteroposterior measurement)
Normal 2-4mm
What is an overbite?
Overlap of the upper anterior teeth over the lowers in a vertical plane
Normal 3-4mm
What is crowding?
Crowding is a common space shortage
How is crowding determine?
Crowding = total tooth size - total arch length
What is mild crowding?
<3mm
What is moderate crowding?
4-5mm
What is severe crowding?
> 6mm
What are common classifications of malocclusion?
Incisor classification
Skeletal classification
Angle’s classification
Indices
What are the 4 categories of incisor classification?
Class I, Class II Div 1, Class II Div 2, Class III
What is Class I incisal relationship?
Lower incisor occludes with or lies directly below the upper incisor cingulum
What is a Class II Div 1 incisal relationship?
Lower incisor edges are palatal to the cingulum plateau of the upper incisors, upper incisors are proclined with an increased overjet
What is a Class II Div 2 incisal relationship?
Lower incisors edges are palatal to the cingulum of the upper incisors, upper incisors are retroclined
What is a Class III incisal relationship?
Lower incisor edges lie anterior to the cingulum of the upper incisors, overjet may be reduced or reversed
What are the three skeletal classifications based on the anteroposterior relationship of the mandible and the maxilla?
Class I, Class II, Class III
How can the skeletal classification be evaluated?
Clinically (profile) or cephalometrically (radiograph)
What is a skeletal class I relationship?
ANB 2-4 degrees (cehphalometrical radiograph value)
Balanced facial profile
What is a skeletal class II relationship?
ANB >4 degrees
Profile shows relative mandible retrusion
What is a skeletal class III relationship?
ANB <2 degrees
Profile shows relative mandibular prominence
What is Angle’s classification?
Based on the buccal segment relationship
Classifies the relationship of the upper and lower first permanent molars
What is an Angle’s class I relationship?
Mesiobuccal cusp of the upper first molar occludes with the anterior buccal groove of the lower first molar
What is an Angle’s class II relationship?
The lower arch is at least half a cusp’s width posterior to class I
What is an Angle’s class III relationship?
The lower arch is at least half a cusp’s width anterior to class I
What are the problems with Angle’s classification?
Incisors not considered
Skeletal pattern is not considered
First molars may have drifted or be absent
Dividing line between categories in unclear
What are the 2 main indices of malocclusion?
IOTN (index of orthodontic treatment need) and PAR (peer assessment rating)
What are the indices of malocclusion used for?
Epidemiology
Treatment priority and resource allocation
Audit of the standard of treatment outcome
Research
What is the index of orthodontic treatment need (IOTN)?
Used for describing the need for treatment
Based on two components- dental health component and aesthetic component
What is the dental health component?
It is a 5 point scale, based on the most severe of the abnormal occlusal features- 1= no treatment needed, 5= very great treatment needed
What is the aesthetic component?
10 point scale, uses standardised series of photographs of the teeth with 1 being normal and 10 being most unattractive
What is the peer assessment rating?
Used for assessing the quality of treatment outcome
Scores allocated before and after treatment
Allows for assessment of the degree of improvement during orthodontic treatment
