MAXILLARY AND CRANIAL BASE CHANGES DURING TREATMENT WITH FUNCTIONAL APPLIANCES

The purpose of this prospective study was to investigate the maxillary and the cranial base changes after treatment with the Harvold activat or and the Frankel function regulator appliances. Forty-two children, who are 10 to 13 years old, with Class II, Division 1 malocclusions we re matched in triads according to age and sex and randomly assigned to either the control, Harvold activator, or Frankel function regulator group. Lateral cephalometric radiographs were taken at the start of th e study and 18 months later. Both appliances reduced the overjet by ti pping the maxillary incisors palatally and, as a consequence, the leng th of the maxillary arch was reduced. The appliances had no effect on either the horizontal or vertical position of the maxillary molars. Sm all, but statistically significant, changes in the cranial base angle in the Frankel function regulator group were attributed to relatively large changes at basion in several children, influencing the results b ecause of the small size of the sample. The appliances had no effect o n the position of the maxilla.