Frankel appliance type III: correct fabrication and case report of skeletal Class III malocclusion

The functional Regulator was developed by Rolf Frankel of Zwickau, Germany in 1966. The Frankel appliance is used to effect changes in sagittal, transverse, and vertical jaw relationships and remove the abnormal muscle forces in the labial and buccal areas that restrict skeletal growth, thereby, providing an environment which maximizes skeletal growth. Four main types of functional regulators have been described by Frankel. They are the FR I, II, III and IV. One of these appliances, the FR-III, is used in the treatment of skeletal Class III malocclusion. This appliance is used during early mixed dentition stage to correct skeletal Class III malocclusion, characterized by maxillary skeletal retrusion and no mandibular prognathism. The correct fabrication of FR-III is required. In order to do it, one must pay attention to the following: mixing the alginate impression material in a thick consistency, optimum vestibular depth, oblique mounting of casts in the vertiiculator, minimum incisal vertical height of construction bite, sufficient working model trimming, rectangular wax relief of the occlusal margin area in the working cast and a palatal bow of 1.2 mm heavy wire. Finally one case is reported.