Occlusion/malocclusion

Question 1

Define occlusion

Answer 1

Arrangement and position of teeth with upper and lower teeth in contact in their usual position

Question 2

Define malocclusion

Answer 2

Tooth position or jaw position outside normal range

Question 3

What is tooth fusion?

Answer 3

Where two individual teeth are fused together. Each tooth has an individual pulp chamber and root canal

Question 4

What is tooth germination?

Answer 4

When two teeth develop together and form one tooth. Visibility the crown of the tooth is large and there is only one root canal

Question 5

What is the cause of a class III malocclusion?

Answer 5

Genetics

Question 6

What are the dental features of a class II division 2?

Answer 6

• retroclined incisors
• increased interincisal angle
• increased overbite
• overjet reduced
• buccal segments class II
• scissor bite maybe present
• proclined lateral incisors

Question 7

What are the skeletal features of a class II division 2?

Answer 7

• AP - usually class I, could be II or III
• vertical - reduced lower anterior face height
• transverse - anomalies can be present, maybe scissor bite

Question 8

What local factors can cause malocclusions?

Answer 8

• variation in tooth number - eg supernumeraries, hypodontia
• variation in tooth form - eg macrodontia, microdontia
• variation in tooth position - eg ectopic canine, transposition
• abnormalities of soft tissues - eg fraenum = midline diastema
• pathology - eg cysts = impacts eruption, scarring
• delayed tooth loss

Question 9

What is the prevalence of Class III malocclusion in the general population?

Answer 9

3%

Question 10

What are the soft tissue features of a Class II Div 2?

Answer 10

• high lower lip lobe
• pronounced labiomental fold
• strap like lip

Question 11

What genetic influences affect malocclusion?

Answer 11

• skeletal pattern
• syndromes
• evolutionary trend to decrease jaw size and tooth number

Question 12

What environmental influences effect malocclusion?

Answer 12

• soft tissues - neutral zone
• habits
• local factors
• pathology
• trauma
• respiration (little effect)

Question 13

What reasons may a tooth fail to erupt?

Answer 13

• supernumerary
• retained deciduous tooth
• crowding
• canines - long path of eruption
• cysts

Question 14

What is infraocclusion?

Answer 14

A tooth remains in its original plane whilst the rest of the arch develops laterally and vertically, making it appear submerged

Question 15

What are possible problems of an infraoccluded tooth?

Answer 15

• space loss
• wedging of primary tooth
• difficult access for OH, restoration or extraction

Question 16

What are signs to watch out for with an infraoccluded primary tooth?

Answer 16

• tooth inferior/lower position to adjacent teeth
• tipping of adjacent teeth
• decrease of arch length
• presence/absence of permanent successor

Question 17

What is crowding?

Answer 17

A discrepancy between tooth and jaw size that results in misalignment of the teeth