The effect of Fränkel's function regulator type III on the apical base.

Dento-alveolar and skeletal effects of orthopaedic treatment have always been the subject of controversial scientific discussions. The objective of this retrospective study was to demonstrate the changes in the dental arch and the apical base of both jaws following therapy with Fränkel's function regulator type III (FR III). For this purpose, 42 Class III patients (28 females, 14 males, mean age 7.5 years) were selected according to strict criteria. The control group consisted of 16 patients (eight females, eight males, mean age 8.3 years) with minor malocclusion symptoms. Study models of all patients at the beginning and end of treatment were evaluated using a sophisticated measuring system. Apart from common parameters of model analysis, cusp inclination of the first molars, and apical bases of the maxilla and mandible were recorded to facilitate a comprehensive evaluation of treatment effects (including growth). The FR III stimulated the development of the maxilla, thus resulting in a more physiological growth pattern. Mandibular prognathism, however, was still discernible after therapy in the Class III patients, even though mandibular growth did not differ significantly between the two groups.