Exo v non exo

Question 1

Space analysis + evidence

Answer 1

Royal London Space Analysis (Kirschen et al. 2000)

Question 2

Components of space analysis

Answer 2

1) Crowding/spacing
2) Levelling
3) Arch width changes
4) Incisor AP changes
5) Angulation
6) Inclination

Question 3

Space analysis calculations

Answer 3

1) AP: 1mm retraction = 2mm arch space/Q
2) Inclincation: every 5 deg retraction reduce 0.5mm OJ
3) COS:
3mm -1mm req
4mm- 1.5mm
5mm- 2mm

4) Expansion:1mm = 0.5mm archspace

5) Distalisation
3mm with HG
2mm -1/2 unit with Invisalign

Question 4

Skeletal factors to consider exo

Answer 4

• vertical: deep v open bite

- AP: camou or sx affect anchorage req

Question 5

Dental factors to consider exo

Answer 5

• crowding
• class ii or iii (exo pattern)
• ectopic tth/tooth agenesis -> prog of tracking/ maintaining archform symmetry
• prog of tth
• bimax
• ML correction

Question 6

Soft tissue factors to consider exo

Answer 6

• perio: thin gingival biotype
• lip incomptence: 4mm separation unaesthetic
• ST profile: changes 60-70% of incisor mvm and stops when lips contact (Jenson et al., 1992)
• beneficial when lips more protrusive than 2-3mm behind E line

Question 7

Non-exo considerations

Answer 7

1) Does not change stability
2) Expansion
3) IPR
4) Profile
5) GM
6) Distalisation
7) OSA

Question 8

Exo spoil profile? evidence

Answer 8

Exo did not change U lip protrusion sig. more than non exo (Xu et al., 2006)

Increase lip thickness protect against sig. reduction of lip curvature depth

Only in faulty dx, tx plan, mechanics
- ST resp. variable and diff to predict