Class I

Question 1

Describe the aetiology of class I malocclusion

Answer 1

Normal AP occlusal relationship (incisor and molar)

But there is a discrepancy in the arches or in the transverse of vertical relationship

Question 2

What is the most common skeletal pattern in class I patients

Answer 2

Class I skeletal pattern 
However may be mild class II or III with dentoalevolar compensation allowing for the class I

Question 3

List some skeletal factors that may contribute to the class I malocclusion

Answer 3

Mild transverse discrepancy 
Increased vertical skeletal proportion and AOB where the AP incisor relationship is class I

Question 4

What is the soft tissue environment in class I malocclusion

Answer 4

Favourable

Question 5

What is the exception in class I malocclusion where soft tissues are unfavourable

Answer 5

Bimaxillary proclination

Question 6

What is bimaxillary proclination

Answer 6

Proclined upper and lower incisors usually occuring as a result of reduced lip tonicity and altered tongue position

Question 7

Class I bimaxillary proclination patients

Answer 7

Increased overjet, but the incisor relationship is still class I

Question 8

What is the most common aetiological factor causing class I malocclusion

Answer 8

Dental factors

Question 9

What are the dental factors that can cause a class I malocclusion

Answer 9

• Tooth size to arch length discrepancy - causing crowding or spacing
• Crowding - can be genetic (above) or due to premature loss of primary tooth
• Displaced teeth
• Impacted teeth
• Anomalies in tooth size, number and form