Effects of the functional regulator III on transversal changes: a postero-anterior cephalometric and model study

Studies assessing the transversal treatment changes caused by the functional regulator III (FR-3) are limited in number. This clinical study was planned to analyse the transversal effects of the FR-3 appliance therapy. The treatment group consisted of 17 patients (8 males and 9 females) with Class III malocclusion, who were treated with the FR-3 appliance. The control group consisted of 17 subjects (7 males and 10 females) with a normal occlusion. Mean ages of the subjects were 10.73 and 10.66 years in the treatment and control groups, respectively. Postero-anterior radiographs and stone casts were obtained before (T1) and after (T2) treatment/observation. The results of the Student's t-test comparing initial values showed that maxillary dentoalveolar and skeletal widths are significantly larger in the control group than those in the treatment group. At the end of the treatment, significant transverse increments occurred only at the dentoalveolar level of the maxilla. The transversal changes in the mandible were not statistically significant. Buccal shields of FR-3 did not stimulate the growth of maxillary apical base but caused an enhanced and supplementary widening of maxillary dental and alveolar structures.