3 - Classificaiton Of Malocclusion

Question 1

Lecture Aims:
1. How to classify malocclusion in all 3 planes of space: Anterior-Posterior, Vertical, and
Transverse.
2. Learn how to assess the face, teeth, and skeletal pattern clinically and using
radiographs.

Question 2

What is orthodontics?

Answer 2

• The study of growth of the craniofacial complex, including the maxilla, mandible and cranial vault.
• Development of the occlusion
• The prevention and correction of occlusal anomalies or malocclusion.

Question 3

Occlusal Terminology:
- Normal Occlusion
- Maloccluion
- Ideal occlusion

Answer 3

Normal Occlusion = Minor deviations from the ideal

Malocclusion = Appreciable deviations from the ideal considered functionally or aesthetically unsatisfactory.

Ideal Occlusion = Andrew’s 6 keys.

Question 4

Classification of malocclusion

Answer 4

• Classification made of face, teeth and skeletal pattern.
• Relating the maxilla and mandible to the cranial vault. Understanding how the teeth are related to the maxilla, mandible and cranial vault.

Question 5

Examination

Answer 5

• Examine the face – Skeletal pattern/soft tissues.
• Examine the teeth – Occlusion classified.
• Examine radiographs – Classify the skeletal pattern

Question 6

Facial Examination:

Answer 6

• The face is first examined in 3 planes of space which gives us a picture of the soft tissues and an idea of the underlying skeletal pattern
• The teeth are then examined both at rest and in function and occlusion needs to be classified
• The radiographs are then examined to classify the skeletal pattern

We confirm our diagnosis with x-rays.

Question 7

The facial examination needs to be done in 3 planes of space:

Answer 7

Horizontal or Transverse
- Symmetry and chin point

Vertical
- Facial thirds and Frankfort Mandibular- Planes Angle

Sagittal or Profile (Anterior-Posterior relationship)
- Class I, II, III soft tissue profile

Question 8

Profile assessment - Sagittal or Profile

Answer 8

Question 9

Profile assessment - how do you carry it out?

Answer 9

Ask the patient to look in the natural head position straight in front of them, like they are looking in the mirror

You are looking to make sure that the face is balanced

The two main points we are looking at are:
- Point A – Deepest concavity just below the nose
- Point B – Deepest concavity in the mandible (just under the lower lip)

Question 10

Profile assessment - Class I profile

Answer 10

Maxilla and mandible are in reasonable balance with cranial base
Intraorally teeth may not be well aligned but if ideal occlusion there will be perfect alignment

Question 11

Profile assessment - Class II profile

Answer 11

One patient has reduced lower face height - blonde patient + can get lips together

Other patient has increased vertical dimension

Question 12

Profile assessment - Class III

Answer 12

Question 13

Facial examination - Vertical

Answer 13

The Frankfort - mandibular plans angle FMPA used to assess the vertical

Question 14

Explain

Answer 14

Question 15

Vertical facial assessment

Answer 15

When assessing the vertical plane, you need to look for balance and harmony in the patients facial thirds:
- Upper third of face
- Middle third of face
- Lower third of face A well balanced face means a patient has equal facial thirds. In orthodontics, we don’t normally look at the upper third of the face, but we focus on how the lower facial third relates to the middle facial third. Clinically we want the proportion between middle and lower thirds to be 50:50
(From glebela to subnasale to soft tissue menton)

Question 16

Vertical assessment
Describe facial balance

Answer 16

Good facial balance

Question 17

Vertical assessment
Effects of increased vertical dimension

Answer 17

Question 18

Vertical assessment

Answer 18

Reduced lower face height

Reduced vertical proportions

Question 19

What can you see here?

Answer 19

Reduced lower face height and has a deep bite

Deep bite = vertical overlap between upper and lower incisors

Had jaw surgery leading to return of facial harmony between uppper and lower part of face

Question 20

Explain

Answer 20

Pt has increase in lower face height
Intraorally - anterior open bite = vertical opening in the front, no overlap between upper and lower incisors

After surgery, well balanced and no anterior open bite and has normal overbite

Question 21

Facial examination - Horizontal or transverse

Answer 21

Question 22

Question 23

Question 24

Examination teeth - Occlusal Classification

Answer 24

Intraoral Examination:
- Incisor relationship
- Molar relationship
- Canine relationship

Question 25

Class I Incisal relationship

Answer 25

Lower incisors must lie below or at cingulum plateau

Question 26

Class II Division I Incisal Relationship

Answer 26

The lower incisor edges occlude or pre- occlude posterior to the middle palatal 1/3rd or cingulum plateau of the upper central incisors. The division I aspect comes from the fact that the overjet is increased, and the upper central incisors are usually proclined, although they can be normal

Question 27

Class II division 2 incisor relationship

Answer 27

The lower incisal edges occlude or pre- occlude posterior to the middle palatal 1/3rd or cingulum plateau of the upper central incisors. The division II aspects comes from the fact that the upper central incisors are retroclined. Most Class II Div II are on a mild skeletal II base, but there are some patients with an increased overjet, but the upper incisors are still retroclined.

Question 28

Class III Incisor Relationship –

Answer 28

The lower incisors edges occlude or pre-occlude anterior to the middle palatal 1/3rd or cingulum plateau of the upper central incisors. If the overlap of the upper and lower teeth are normal, then the patient will appear to have normal vertical proportions.

Question 29

Molar relationship Angle’s Class I molar relationship Andrew’s Class I molar relationship

Answer 29

Question 30

Molar relationship Class II

Answer 30

Question 31

Molar relationship Class III

Answer 31

Question 32

Canine relationship Class I

Answer 32

Question 33

Canine relationship Class II

Answer 33

This can also be Full unit or half unit class II In full unit, the upper canine is in the embrasure between the lower canine and lateral incisor In half unit, the upper canine cusp is in line with the lower canine cusp.

Question 34

Canine relationship Class III

Answer 34

Full unit 3 shown below If occluding cusp to cusp - half unit 3

Question 35

Radiographic skeletal classification

Answer 35

Lateral Skull Cephalometric Radiograph – The relationship of how the maxilla is related to the mandible and the cranial base. It can be classified as Skeletal Class I, II or III. The cranial base is marked by the two yellow points on the top of the radiograph: The sella (the middle of the sella turcica) and the nasion (junction of the frontal bone and nasal bone). With cephalometric radiographs, there is some degree of magnification, so this will affect some of the measurements. However, we are also interested in angular measurements, and these are not affected by magnification

Question 36

Standard cephalometric landmarks Identify below

Answer 36

Question 37

Question 38

Cephalometric skeletal classification Identify 2 commonly used analysis to classify the skeletal pattern and what they are:

Answer 38

Question 39

Cephalometric skeletal classification Eastman analysis What do we measure?

Answer 39

Question 40

Question 41

Question 42

PLEASE LOOK AT Classification of malocclusion summary on Notability