Dimensional changes in dental arches after treatment with a prefabricated functional appliance.

The purpose of this study was to determine the effect of the T4K, a prefabricated functional appliance, on the transverse and anterior-height dimensions of the maxillary and mandibular dental arches. Dimensions before and after treatment were measured on the sample, then, natural growth was subtracted from the treatment effects and compared with twice the error of the method. A clinically significant increase of both dimensions was observed in the maxilla and mandible when Class II malocclusion patients were treated with the T4K. Therefore, this retrospective study demonstrates that T4K is a valid treatment choice at an early age when transverse expansion is part of the treatment goal.