Purpose : to evaluate three dimensionally the dentoalveolar changes concurrent with maxillary expansion utilizing Quad-helix appliance.Material and methods: This study was carried out on 8 patients who received expansion using Quad-helix appliance. The appliance was activated 2 mm every 1 month for 3 months. Cone beam computed tomography scans (CBCT) were taken before and after expansion. In vivo 5.1 Anatomage software* was used to evaluate the effects of quad-helix appliance.Results: Quad-helix appliance resulted in statistically significant increase in post-expansion measurements of U3 coronal width, U4 coronal width, U5 coronal width, U5 apical width and U6 coronal width than pre-expansion measurements. Post-expansion measurements of UR4, UL4, UL5 and UL6 inclination showed a statistically significant decrease than pre-expansion measurements (denoting increase of buccal tipping of these teeth)Conclusion: The appliance resulted in expansion in the skeletal and dental level. It resulted in buccal crown tipping of the expanded teeth (controlled tipping).