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Updated: Jul 4, 2026
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Finite Element Analysis Model for Assessing Expansion Patterns from Surgically Assisted Rapid Palatal Expansion
Published on: October 20, 2023
Changes in arch form following surgically-assisted rapid maxillary expansion (SRME)
Karl-Friedrich Krey1, Frank Walter, Karl-Heinz Dannhauer
1Department of Orthodontics, Dental School, University of Leipzig, Germany. krek@medizin.uni-leipzig.de
Summary
Surgically-assisted rapid maxillary expansion (SRME) shows significant tooth movement and inclination changes. Including canines and second molars in the appliance is recommended to minimize relapse in severe crowding cases.
Area of Science:
- Orthodontics
- Maxillofacial Surgery
Background:
- Surgically-assisted rapid maxillary expansion (SRME) is common for adult transversal discrepancies.
- Limited data exists on individual tooth movement, inclination changes, and arch form alterations post-SRME.
Purpose of the Study:
- To detail transversal tooth movement, inclination changes, and arch dimension alterations after SRME.
- To assess changes after active treatment and a 3-month retention period.
Main Methods:
- Analyzed 31 patient casts post-SRME using a 3D reflex microscope.
- Evaluated changes after active expansion and a 3-month retention phase with a blocked Hyrax appliance.
Main Results:
- Second molars moved 28% less than total expansion; anchorage teeth showed greater buccal tipping than second molars.
- Arch length increase matched anchorage expansion, but sagittal arch decreased during retention.
- Canine and second molar expansion reduced to 68% by 3 months; anterior arch length increased by only 50%.
Conclusions:
- Significant relapse and inclination changes occur post-SRME.
- Including canines and second molars in the appliance is crucial for minimizing relapse in severe crowding.
