Is the semi-rapid or rapid expansion route more beneficial for the correction of asymmetries and cheekbone development?
Many posts on this forum have conflicting information and It has been quite difficult to discern which are more accurate. Some users claim that rapid maxillary expansion results in more skeletal movement and hence greater cheekbone development and correction of the asymmetric maxilla, however, others say that rapid does not provide as much change in facial profile compared to conventional slow or semi-rapid expansion. With the reverse also being true.
Any help would be appreciated.
With rapid palatal expansion, it depends on whether the split is parallel or not, if the split is not parallel you'll get more anterior expansion and little posterior expansion, posterior expansion has the biggest affect on cheekbones. So something like MSE is more likely to get a parallel split and hence greater cheekbone change, just look at Ronald Ead, with something like RPE (tooth-borne) you're not going to notice a lot of cheekbone change because the split is affecting the anterior maxilla more than the posterior maxilla. There's other factors that go into this, like the MSE dragging through bone or pushing the teeth instead of the bone, but let's just say the appliance successfully splits the suture as it's intended, MSE (bone borne) will more likely split parallel, RPE (tooth borne) will split mostly anteriorly.
With semi-rapid expansion, this depends on tooth tipping, ofc you can still get expansion in the maxilla even if your teeth tip, if you've expanded your IMW 10 mm and 3 mm is due to teeth tipping, that's still 7 mm of expansion, just an example. However with this example you will understand that change in the IMW does not necessarily translate to change in the maxilla. Ideally you want an increase in IMW while the teeth stay upright, or at the very least with minimal tipping.
@sinned thank you for the in-depth response, will there be cheekbone change if theres purely remodelling through the semi-rapid option?