First permanent molar in orthodontics Flashcards
When is the best time and position of teeth to extract 6’s from ortho prespective?
Age 8.5-10 year old
Class I occlusion
Mild incisor crowding
All permanent teeth present
What are the implications for loss of 6’s?
Disturbs occlusion - if lower, the upper may overerupt, 7 may move laterally
Orthodontic treatment prolonged
Treatment may be more difficult
Patients unsuitable
Why is orthodontic treatment prolonged?
Patients: high caries rate, doubtful co-operation and motivation for treatment More teeth need to be moved Acrylic button (nance button) attached to 7's to stop them drifting forwards
What are the are problems with 1st permanent molar?
Geographical inequality
Socio-economical group inequality - higher in groups IV and V
What are the factors influencing success that need to consider with extraction of 1st permanent molars
Degree of crowding/hypodontia
Upper or lower
Timing of extraction
Balancing and compensating extractions
How will whether 6 is upper or lower affect the success?
They have different eruption paths
Lower 6 is the problem, upper 6 rarely has problems
What are the problems with the removal of the lower 6’s?
7’s:
Tilts mesially
Rotates mesio-lingually - doesn’t give food contact with upper
Leans lingually
Over-eruption
Upper 7’s have more vertical point of eruption, lowr 7’s have more mesial path of eruption
What is a positive with overeruption of 6’s?
stop any mesial movement of lower 7’s
if there is occlusal contact then will be ok
When should 6’s be removed straight away without waiting for ortho treatment?
Unrestorable 6 symptomatic
Ortho treatment unlikely e.g. caries
7 fully through, so will not move much
What happens if the lower 6 is extracted too late?
minimal space closure
Lower 6’s extracted too early?
lower 5 can become ectopic or drift distally
When may you retain the 1st permanent molars for ortho later?
High caries risk in all 6’s
When is the ideal time to take out 6’s? What can this result in?
when have bifurcation of 7’s just forming
&’s mesially tipped so that now contacting the 5’s
7’s replace the 6’s
What are other favourable factors for when to extract 6’s?
Lower 5 engaged in bifucation of E
Lower 7 mesially angulated
Lower 8 present
What is compensating extractions?
Extraction in the opposite arch in the same side - may want to consider compensating 6’s
What is balancing extractions?
Extraction in the same arch on the opposite side
Dont need to balance 6’s, too far back to affect centrline
How does extraction of 6’s affect 7’s?
Tilts mesially
rotated mesio-lingually
Leans lingually
upper 6 may over-erupt
What is the problem with alveolar necking and orthodontics?
Lots of cortical bone in the extraction site so when heals makes it more difficult to close orthodontically
Less likely to get spontaneous space closure
What can extraction of 6’s prevent happening?
Prevents impacted 8’s
More space created posteriorly
If class II malocclusion what may you consider with extraction of 6’s
Extract 6's early and correct class II with functional appliance or maintain and incorporate into ortho treatment plan as dont know how much they will grow
If class III malocclusion what may you consider with extraction of 6’s
Seek orthodontic opinion as treatment may be delayed to assess mandibular growth
Timing of extraction can alter if orthognathic surgery planned
