Objective To evaluate the clinical effect of semi-attached quad-helix appliance in expanding the narrow maxillary arches in patients with cleft lip and palate. Methods 15 cases with cleft lip and palate were selected and treated by semi-attached quad-helix appliance. Before, during, and after treatment, the dental arch width between cuspid, the first premolar and first molar were measured. Results The upper dental arches of all patients were expanded effectively in about five months. After orthodontic treatment, the upper dental arches were expanded, and the teeth were alined regularly, which provided good conditions for alveolar bone grafting. Conclusion The semi-attached quad-helix appliance with the fixed orthodontic treatment can expand the narrow maxillary arches in patients with cleft lip and palate effectively and conveniently.
