Qasim Saeed, Riaz Qazi, Aqib Sohail.
A cephalometric study of the effects of screw height on rapid maxillary expansion.
Biomedica Jan ;20(2):99-103.

This study was undertaken to compare the skeletal expansion effects of rapid maxillary expansion (RME) using either a shallow or deep height of Hyrax expansion screw. The study includes i6 patients with narrow maxilla and mild to moderate crowding of the maxillary arch. Rapid maxillary expansion was performed in half of the patients with the shallow Hyrax expansion screw and other half with the deep screw. The angular and linear changes related to the maxilla were analyzed with Wilcoxon signed ranking test comparing posterior anterior (PA) cephalometric films obtained before and after rapid maxillary expansion. Both appliances were equally effective in skeletal expansion of maxilla. The deep screw appliance was more effective in increasing the nasal width.

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