Original Article

A Comparison of Rapid Maxillary Expansion and Quad-Helix Applications in the Late Mixed Dentition


  • Muammer Üşümez
  • İlter Uzel

Turk J Orthod 2008;21(3):187-195

Current study aims to evaluate and compare the dental and skeletal effects of Quad-Helix (Q-H) and Hyrax (RME) appliances. The study was conducted on 10 females and 10 males at Gulhane Military Medical Academy, Ankara, Turkey. The mean age of the group before treatment was 11.4±1.3 years. Two study groups were developed and the first group received Hyrax treatment while the other group was treated with the Q-H appliance. In both groups pretreatment (T1) and posttreatment (T2) dental casts and lateral cephalograms were collected. Dental cast measurements included intermolar (IM) and intercanine (IC) measurements and cephalometric measurements included SNA, SNB, ANB, SN-GoMe and SN-Occ measurements. The data was subjected to statistical analysis using Wilcoxon and Mann-Whitney U tests. IM and IC increases at T2 were 6.4±2.4 and 3.6±2.1 mm respectively. These increases were statistically significant for both groups (P<0,001). There was also a significant increase of SNA angle in both groups and another significant increase of ANB angle in the RME group (P<0.05). No statistically significant differences were observed between groups (P>0.05). Within the limitations of this study it can be concluded that RME and Q-H applications produce similar results in the age group studied.

Keywords: rapid maxillary expansion, quad-helix, early treatment