Dimensional Alterations Provoked by a Bonded Expander, with Two Activation Patterns

Rosana Villela CHAGAS, Cristiane Assis CLARO, Gerval de ALMEIDA, Weber URSI

The objective of this paper was to verify the effect on the axial inclination of the first permanent molars using two activation regimens with a bonded rapid maxillary appliance. Twenty eigth children between the ages of 7 to 10 , being 6 males and 21 female, from the Discipline of Orthodontics of the Departament of Dentistry of the University of Taubaté were selected. All patients presented maxillary constriction that was suitable for this procedure. Model cast, lateral and P-A cephalometric, as well as panoramic and occlusal radiographs were obtained before and after the expansion. Patients were randomly assigned to two different expansion rates, either one turn per day (14 children) or four turns per day (13 children). The appliances were activated until the screw opening reached 8mm. The appliance were stabilized for 5 months, removed and a maintenance acrylic plate placed.On the before and after expansion study cast measurements between the permanent upper molars were obtained using Zeiss (model Numerex C - 100 N) precision machine for tri-dimensional measurements. Using various reference points, it was possible determine the effect on the axial inclination of the first permanent molars of the two expansion rates. It was concluded that both rates of activation provoked similar effect on the appliances anchor teeth.

Keywords: Rapid maxillary expansion. Symmetrical expansion. Upper dental arch shape.

Saturday, December 28, 2024 23:51