9 - Interceptive orthodontics 2

Question 1

Describe the aetiology of infra-occluding teeth.

Answer 1

Ankylosis of primary tooth, bone continues to grow around tooth and tooth begins to disappear

Question 2

How do you diagnose an infra-occluding tooth?

Answer 2

• percussion (dull note)
• check mobility
• radiograph to confirm absence of successor, ankylosis and root resorption

Question 3

How do you manage an infra-occluded tooth that has a successor?

Answer 3

• monitor 6-12 months if mild
• XLA if below contact point, or permanent root is near completion
• maintain space if XLA

Question 4

What are the risks of not treating an infra-occluding tooth that has a successor?

Answer 4

• successor becomes more ectopic
• adjacent teeth can tip and primary tooth become impossible to XLA
• caries
• perio

Question 5

How do you manage an infra-occluded tooth that does not have a successor?

Answer 5

• treatment depends on crowding, degree of infra-occlusion and malocclusion
• retain primary if in good condition and consider onlay
• XLA if below contact point
• if XLA, plan space management

Question 6

How do you plan space management for XLA of an infra-occluded tooth?

Answer 6

• maintain space for prosthetic tooth
• reduce space to one premolar unit (better interdigitation)
• close space with fixed

Question 7

What components can you use to maintain space in the arch?

Answer 7

• band and loop space maintainer (fixed)
• wire stop
• Adam’s clasps
• PMMA extended round mesial/distal surfaces of adjacent teeth to prevent movement

Question 8

What are dental consequences of ectopic canines?

Answer 8

Resorption of central and lateral incisor roots

Question 9

How can you intercept with ectopic canines?

Answer 9

• XLA of C
• RME
• consider space maintainer

Question 10

What are the risks of not intercepting ectopic canines?

Answer 10

• permanent successor becomes more ectopic
• permanent canine becomes impacted
• root resorption of adjacent teeth
• cyst formation (rare)
• ankylosis of unerupted canine

Question 11

How do you intercept a class III occlusion?

Answer 11

• be very wary, wait for growth to stop
• no irreversible treatment should be given to those with class III
• enhance maxillary growth with RME/protraction headgear/reverse twin block
• bone anchored maxillary protraction (Bollard implants)

Question 12

How do you camouflage a class III occlusion?

Answer 12

URA with bite plane

Question 13

Why is it important to treat a class II early?

Answer 13

• risk of trauma and incompetent lips
• appearance may cause bullying or low self esteem
• more difficult to correct after growth stopped

Question 14

What is the overjet measurement for an IOTN 4a?

Answer 14

> 6mm

Question 15

What is the overjet measurement for an IOTN 5a?

Answer 15

> 9mm

Question 16

How do you intercept a class II malocclusion?

Answer 16

• twin block
• Frankel 2