Posterior Crossbite

The aim of this prospective clinical study is to evaluate and compare the changes in occlusal force distribution using a quantitative digital occlusal analysis system following piezocision-assisted rapid maxillary expansion (RME) in adolescent versus young adult orthodontic patients. The study hypothesis is that piezocision-assisted RME will result in significant changes in occlusal force distribution and that these outcomes may differ between age groups over a 3-month follow-up period.

Design: Two-arm parallel randomized clinical trial in mixed dentition (6-12 years). Arms: (1) 9 mm, 900 g leaf expander; (2) 9 mm Hyrax expander. Follow-up: From appliance insertion → completion of intended expansion → 6-month retention. Primary outcome: Pain perception during the first 7 days post-insertion (daily patient-reported scale). Secondary outcomes: Skeletal and dental changes on CBCT.

This randomized clinical trial aims to evaluate and compare the effectiveness of the Quad Helix (QH) appliance versus Rapid Maxillary Expanders (RME) in treating posterior cross-bite in Egyptian children during the mixed dentition stage. The study will also assess patient comfort and pain levels associated with each appliance.