XLAs and Ortho Revision Questions

Question 1

Balancing XLA

Answer 1

XLA of tooth from opposite side of the same arch - minimise midline shift

Question 2

Compensating XLA

Answer 2

XLA of tooth from opposing aech of same side - minimse and maintain occulsal relationship

Question 3

Molars

Answer 3

more spaice loss with E’s>D’s, upper>lower
6’s drift mesially and steal 5’s space
tend not to balance or compensate

Question 4

If XLA in lower arch

Answer 4

must XLA in upper to avoid Class III

Question 5

If no XLA in lower arch

Answer 5

can XLA in upper - Class II

if no XLA then might need to distabilise upper molars using headgear to get Class I relationship

Question 6

Carious 6’s

Answer 6

XLA lower - take upper aswell (compensating) as don’t want upper erupting into lower gingivae

XLA upper - dont need to take lower as don’t erupt as much

Question 7

A/B

Answer 7

no effect on permanent dentition so no need to balance or compensate

Question 8

C’s

Answer 8

lose 1C midline shift off to that side

balance with XLA on other side

Question 9

D’s

Answer 9

small shift not as bad as C’s

Question 10

E’s

Answer 10

don’t balance - little effect on midline

causes mesial drift - happens more commonly in upper than lower arch