Extractions

Question 1

What factors do we consider when deciding which teeth to extract?

Answer 1

• Location and severity of crowding
• Anchorage requirements
• Prognosis of teeth
• Position of teeth
• Patient factors

Question 2

How severe does crowding have to be to consider extractions?

Answer 2

Moderate-severe

- Never say you will extract to correct mild crowding!!!!!!

Question 3

How does location of crowding affect where we extract?

Answer 3

Ideally extract as close to crowding as possible to limit amount of movement required and reduce risk of anchorage loss

Question 4

What does anchorage requirement determine?

Answer 4

Whether the 4 or 5 will be removed

Question 5

What will be the extraction pattern for: Class I moderate-severe crowding

Answer 5

44/44 for severe as it gives maximum space to correct crowding
OR
55/55 if moderate

Question 6

Why do we extract the same teeth in both arches in class I?

Answer 6

It prevents altering the molar relationship (We want it to remain class I)

Question 7

What will be the extraction pattern for: Class 2 div 1 with moderate crowding

Answer 7

44/55
Upper 4s removed to aid OJ reduction and correct canines into class I
Lower 5s to prevent retraction of lower labial segment and corrects molar relationship

Question 8

What will be the extraction pattern for: Class 3 with moderate crowding

Answer 8

55/44

Camouflages reverse OJ and retroclines LLS

Question 9

What will be the extraction pattern for: Class 2 with well aligned lower arch

Answer 9

Upper 4s only because it aligns labial segments but maintains the molar relationship

Question 10

When would you consider removing 6s?

Answer 10

Only if they are of poor prognosis e.g. hyper plastic or carious, developmental conditions

Question 11

Why is removing 6s not ideal?

Answer 11

The 6 is too posterior to provide space for crowding (which usually occurs anteriorly) and correction of incisal relationship

Question 12

Importance of timing in extraction of 6s

Answer 12

• Ideally age 9-10 to allow spontaneous space closure with 7s
• Not if the dentition is crowded though

Question 13

How would you approach extraction of 6s in a crowded dentition

Answer 13

Wait for 7s to erupt to prevent space loss (extracting early will result in teeth moving into extraction space) and prevent medial tipping of 7s

Question 14

How can radiographs indicate correct timing for removal of 7s

Answer 14

Calcification at the bifurcation of the unerupted 7s

Question 15

When would extraction of canines be indicated

Answer 15

Poor prognosis e.g. severely displaced or impacted that cannot be saved surgically or are resorbing roots of incisors
Caries not as important as it doesn’t commonly affected

Question 16

Indications for extraction of lower incisor

Answer 16

• Moderate class III malocclusion to shorten the mandibular arch and retried lower incisors
• Supplemental tooth
• Excluded from the arch/ ectopic eruption
• Macrodontia
• trauma

Question 17

What happens when you remove 4 premolar units?

Answer 17

Always results in class I molar

Question 18

What happens with removal of 2 upper premolar units only?

Answer 18

Full unit class II molar relationship no matter what you started with

Question 19

What happens with removal of 2 lower premolar units only?

Answer 19

Full unit class III molar relationship no matter what you started with

Question 20

How can you restore aesthetics if canines

Answer 20

Modify crown of 4s to look like a canine or orthodontically rotate the 4 so the palatal cusp faces palatally

Question 21

What is an alternative to removing an incisor to overcome crowding

Answer 21

interdental stripping

Question 22

Indications for removal of an 8

Answer 22

Not important for orthodontic as too posterior and erupts too late
- Repeat pericoronitis or caries distal of the 7