FPM

Question 1

what is the ideal timing and situation for extraction of FPM?

Answer 1

ages 8-10 years

mild crowding

class I

all permanent teeth present including 8s radiographically

unerupted 5 - NOT distally inclined

lower arch - radiographic - evidence of early dentine calcification within 7 root bifurcation

upper arch - radiographic - developmental position of unerupted 7 usually favourable to achieve a good occlusion

Question 2

what can occur if FPM XLA is too early?

when is too early?

Answer 2

before the age of 8 years

lower 5s drift distally - leaves large space between lower premolars
at this point we do not know if 8s are present and will complete the molar dentition

Question 3

what can occur if FPM XLA is too late?

Answer 3

spacing between 5 and 7
7s become fixed to a point and tip mesially and rotate mesiolingually without closing the space
- this often leads to poor occlusal contact and scissor bite

atrophy of alveolar bone if space closure is incomplete - bone gets thin and flat

Question 4

what to do in situation where

class I minimal crowding 
with poor prognosis 6s

Answer 4

extract 6s at ideal time
7s replace 6s

unlikely to need extractions for ortho
do not balance in either arch

Question 5

what to do in situation where

class I crowded 
with poor prognosis 6s

Answer 5

option 1 - aim for ideal timing
then premolar XLA to relieve crowding when permanent dentition has erupted

option 2 - delay FPM extraction until 7s have erupted and utilise the space to relieve crowding
extract the 6s later for orthodontic treatment

Question 6

what to do in situation where

class 2 
with poor prognosis 6s

Answer 6

lower arch - ideal time

upper arch - maintain 6s and extract when needed for ortho treatment
temporise upper FPM

Question 7

what to do in situation where

class 3 
with poor prognosis 6s

Answer 7

upper FPM XLA should be avoided if possible

keeping 6s will aid with correcting the incisal relationship

Question 8

what is a balancing extraction?

Answer 8

removing a similar tooth from contralateral side of same arch

Question 9

what is a compensating extraction

Answer 9

removing a similar tooth on same side of opposing arch

can prevent over-eruption