Sx first Flashcards
What Sx first/ early sx
Beginning of the treatment cycle without preop ortho preparation or with a minimum preoperative orthodontic treatment of less than 6 months
Adv of sx first
Ngan & Moon 2015
- Short prep time -> reduce overall treatment time
psy benefits:
- addresses pt aesthetic concerns early
- no worsening of profile during ortho prep
- better pt motivation/ co-operation
OTM:
- RAP effect
- rapid creation of functional environment for ortho mvm
Disadvantages of sx first
- difficult to match dentition without proper decomp
- easy to underestimate magnitude of sx change req
(where the tth fit best may not result in optimal jaw position without decomp)
Indications
- mild to mod amt of decomp
NOT recommended for those req. major decomp
(Ngan and Moon, 2015)
highly motivated pt
minimal arch length discrepancy
mild to moderate transverse, vertical and sagittal discrepancies
normal incisor inclinations
minimal dental compensations, to avoid interferences during the surgical correction.
Mahmood et al.,2018
Early sx?
Initial presx ortho for:
severe dental crowding
complex three dimensional (3D) dental comp caused by facial asymmetry, including ML deviations.
- to correct crowding and transverse before sx
Mahmood et al., 2018
Complication rate btw sx first and conventional
NO diff
Mahmood, 2018
Relapse of sx first vs conventional
Mx: NO sig diff
Mn: ACW Mn rotation more in sx first group
- unfavourable post op stability
Wei et al., 2018
- meta-analysis challenges prev. systematic reviews that found no difference e.g Yang et al., 2010 (only 6 studies)
Reasons for sx first instability
MAIN reason:
compressive force of Masseter on bony segment
- complicated by having unstable post-op bite
2) Mn autorotation after removal of sx splint
3) Aceclerated OTM with RAP -> immediate rotational relapse
Mn protrusive relapse may occur during initial stages of post-op ortho
Wei et al., 2018
