Extractions in orthodontics Flashcards
What is the only alternative to extraction?
Expansion
Anterior - procline incisors
then distalise using headgear
What is the problem with anterior proclination?
causes bimaxillary proclination:
Affects the appearance, stability, periodontal health
reduces the prognosis of teeth
What causes relapse with anterior proclination?
Lips push force back
What can happen to posterior teeth if have early non-extraction treatment?
7’s and 8’s can be impacted
When may you take out 3rd molars?
In 3 out of 4 cases where teeth have not been removed during treatment there are good reasons for removing wisdom teeth in mid-late teens
What are the reasons for extraction?
Relieve crowding Correct incisor relationship - reduce an overjet/camouflage in class III Overbite correction To correct the centrlines Anchorage
What are the principles of extractions in orthodontics?
- Condition of teeth
- location of crowding
- Position of the teeth (crowns/apices)
- Appliance treatment proposed - patient attitude
What is a compromised extraction pattern?
When have to take out the teeth with poor prognosis rather than the ideal teeth (premolars)
What does a clinical pink spot mean?
Root resorption
If lose an upper central incisor what can be done with the space?
Preserve the space with space maintainer
Close the space - crown on the lateral incisor
When would you extact central incisors?
Rarely indicated
If have poor prognosis
When would you extract lateral incisors?
Poor prognosis
For Symmetry
If severely displaced
When would you extract the tooth close to crowding?
Class III camouflage
Relief of crowding
LR2 displaced
What are the problems with lower incisor extractions?
Compromise the occlusion
Increases the overjet and overbite
Increases upper crowding
When are canines extracted?
Gross displacement Quicker treatment (than alignment if ectopic)
What are the problems with canine extractions in the upper arch?
Upper arch: space between 2 and 4 opens, poor aesthetics
Lower arch: poor contact between 2 and 4
Canines have the biggest root and last the longest
Why are 1st premolars good to extract?
Good anchorage balance
Good for correction of class II and class III and anterior crowding as close
Dont eant to extract anteriors because of aesthetics
Can do mesial movement of 5’s and 6’s to close space
What are the problems with 1st premolar extractions?
May give too much space - 7mm per tooth
Possible effect on patient profile - poor treatment planning and poor mechnics
No evidence
What is the problem with extraction of 2nd premolars?
Changes anchorage balance
Take out upper 5’s, more mesial movement of molars - less space anteriorly, more anterior teeth to distalise
Larger anchor unit anteriorly - determined by having a larger root SA anteriorly
Why extract 1st molars? Problems?
Removes teeth of poor prognosis
Larger teeth, takes longer to close the space, need to retract all the teeth to resolve any crowding
When to extract 2nd molars?
If 3rd molars are impacted
7’s of poor prognosis
Cannot be used to releive anterior crowding - in lower arch have nothing to distalise the 6’s
What are the alternative asymmetric extractions?
Within the arch
Between the arches
Depends on the malocclusion - if class II usually extract upper 4 and lower 5
How does the appliance treatment proposed have an effect on extractions?
If using a removable appliance then can only tip teeth, dont extract any teeth
