MAXILLARY EXPANSION DEVICE
RAPID MAXILLARY EXPANSION (RME)
a) Per day 0.5 mm
b) Key turn/ activation :-
- ¼ turn twice daily or
- Quarter turn twice daily or,
- 0.25 mm twice daily
c) Eg: Hyrax
- Ratio =𝑑𝑒𝑛𝑡𝑎𝑙/𝑏𝑜𝑛𝑒= 1: 1
- The ratio of dental & skeletal expansion obtained after RME is 1 : 1

SLOW MAXILLARY EXPANSION (SME)
a) 0.5 mm per week*
b) eg: quad helix
c) unwind the coil(no key system)