Dentofacial effects of two facemask therapies for maxillary protraction

To compare the dentofacial effects of maxillary protraction with two facemask therapies in growing Class III patients: facemask in association with miniscrew implants (MSI/FM) and facemask with rapid maxillary expanders (RME/FM).

Forty-three Chinese patients with Class III malocclusion and maxillary deficiency were randomly assigned to a MSI/FM sample of 20 patients and a RME/FM sample of 23 subjects. The changes in dentofacial cephalometric variables from the beginning (T1) to the end of treatment (T2) were compared with t-test for paired samples in both groups and for independent samples between the two groups.

No significant cephalometric differences were observed between the two groups in active treatment effects except for maxillary dental variables. However, significant favorable changes in both maxillary and mandibular skeletal components were noted in two groups after treatment. Sagittal measurements showed the maxilla was advanced, mandibular projection was reduced, and the relative sagittal intermaxillary discrepancy improved. Patients experienced additional unfavorable outcomes of clockwise rotation of the mandible as well as retroclination of the lower incisors. The soft tissue profile was improved remarkably in both groups. Proclination of the maxillary incisors and mesialization of the maxillary dentition were significantly different between the two groups. The increases in U1-SN, U1-VR, and U6-VR were 6.41°, 2.78 mm, and 1.24 mm less in the MSI/FM group than in the RME/FM group, respectively.

Compared with the RME/FM therapy, the MSI/FM protocol using a smaller magnitude of protraction force improves skeletal relationships and soft tissue profile and reduces the undesired dentoalveolar effects.