Comparison of maxillary protraction anchored in miniplates and miniscrews: three-dimensional dentoskeletal analysis

Abstract

The aim of this study is to compare the skeletal and dentoalveolar changes produced by three protocols of maxillary protraction with bone anchorage. Material and Methods: The sample will comprise 61 individuals, of both sexes, ages ranging from 9 to 13 years, with class III skeletal malocclusion. Group 1 will consist of 18 individuals treated with class III elastic anchored in a hybrid expander (with two palatal miniscrews) and 2 miniscrews in the distal of the mandibular permanent canines. Group 2 will consist of 18 individuals treated with a fixed nickel-titanium coil spring anchored in a hybrid expander and in 2 mandibular miniscrews positioned distally to the permanent canines. Group 3 will consist of 25 individuals treated with a class III elastic anchored in two miniplates positioned in the infra-zygomatic crest and two miniplates in the mesial of the mandibular permanent canines. Cone-Beam Computed Tomography (CBCT) and digital dental models will be obtained at the beginning and end of treatment. In the CBCTs, the structures of the skull base will be superimposed for a three-dimensional comparison of skeletal changes in the maxilla and mandible. In digital dental models, a palatal rugae superimposition will be performed to compare the dentoalveolar changes promoted by both therapies. The skeletal maturity will be assessed to compute the influence of bone maturation on the magnitude of maxillary protraction. The paired t test will be used for intragroup comparisons. The analysis of variance will be used for intergroup comparisons. Logistic regression analysis will be used to verify the influence of skeletal maturity in maxillary protraction. A significance level of 5% will be regarded for all tests. (AU)