Automatic Metal-free Maxillary Expansion in Pediatric Patients: Clinical Evaluation of the PA12 Zeroexpander® Device - A Pilot Study

Aim: This study evaluates the clinical effectiveness of the ZeroExpander® device in maxillary expansion treatment in pediatric patients with transverse deficiency. It is a metal-free, fully digital device, belonging to a new generation of automatic orthodontic appliances, designed to deliver a constant and controlled expansion force without the need for manual activation or home compliance. Methods: Five patients in mixed dentition with maxillary transverse deficiency were included. Devices were designed using a CAD-CAT digital workflow and manufactured in PA12. Transverse measurements were obtained from pre-treatment (T0) and post-treatment (T1) intraoral scans at the level of canines (C), first primary molars (D), second primary molars (E), and first permanent molars (6°). Statistical analysis was performed using paired t-tests (p < 0.05). Results: Mean expansion was +2.93 mm at the intercanine level, +3.52 mm at the first primary molars, +3.65 mm at the second primary molars, and +0.91 mm at the first permanent molars. Intermolar changes (D, E) were statistically significant (p < 0.01), whereas intercanine and permanent molar changes were not significant. Conclusions: The ZeroExpander® device in PA12 demonstrated clinical effectiveness and stability in treating transverse maxillary deficiency in pediatric patients. Its metal-free design and digital workflow make it an innovative, biocompatible solution, also suitable for patients with special needs.