Fixed orthodontic appliances for maxillary expansion in early mixed dentition

Relevance. Fixed orthodontic appliances for the prevention and treatment of malocclusion during the early mixed dentition remain underused in clinical practice. Materials and methods . Three groups of patients aged 7 to 9 years with maxillary underdevelopment were analyzed. All patients were treated with fixed appliances. Each group included 10 patients; the total sample comprised 15 boys and 15 girls. None of the patients had previously received orthodontic treatment or had craniofacial syndromes. All patients presented with posterior crossbite associated with maxillary deficiency. The appliances were worn for 6 to 12 months, followed by a 4-month retention period. Results . In the first group, patients were treated with a Haas-type rapid maxillary expander and a Marco Rosa–type expander; in the second group, with 2 × 2, 2 × 4, and 2 × 6 partial fixed appliances; and in the third group, with a Hyrax-type rapid maxillary expander. The appliances used in the first and third groups were custom-fabricated in the laboratory. The expansion screw was activated at home by one-quarter turn twice daily, in the morning and evening, for 5 days, then once daily for 15 days, and thereafter by one-quarter turn every 5 days for 6 to 8 months until the desired expansion was achieved. Treatment outcomes were assessed before treatment and after expansion. Conclusion . All appliances provided effective maxillary arch expansion. In addition to expansion, the partial fixed appliance also promoted arch lengthening and normalization of incisor position within a shorter treatment period.