Skeletal, Dental, and Nasal Changes After Slow Maxillary Expansion Using Quad-Helix

The objective of this study was to assess the transverse maxillary skeletal, dental, and nasal effects of quad-helix treatment (slow maxillary expansion) in comparison to an untreated group. This study was performed on 24 patients. Before and after treatment, CBCT images for children who were treated with Wilson quad-helix were retrieved. The treatment group included 12 children with a mean age of 11.4 ± 1.2 years. The untreated control group had 12 matching patients aged 11.7 ± 0.7 years. AVIZO software (version 9.1) was utilized to place specific 3D anatomical landmarks. The segmentation of the nasal airway was performed using Mimics. The maxillary inter-molar width and inter-premolar widths increased significantly in the treatment group but not in the comparison group. These increases were statistically greater between groups. This study showed statistically significant increases in maxillary inter-molar and inter-premolar widths in patients who were treated with Wilson quad-helix to expand their upper arch. Buccal translation in the upper molars resulted after treatment. Quad-helix treatment caused more dental than skeletal effects. The nasal volume and surface area in the quad-helix group significantly increased.