A jointed fan-type expander: a newly designed expansion appliance for the upper dental arch of patients with cleft lip and/or palate.

Abstract

Most patients with repaired cleft lip and/or palate have malocclusion and show various forms of occlusal discrepancy between the upper and lower dentition. In unilateral clefts, the teeth in the collapsed small segment are usually in lingual crossbite, although in most cases they are in normal buccolingual occlusal relation in the molar region. Expansion appliances should fulfill the following functions: the application of expansion force to the alveolar bone of the maxillary complex without buccal tipping of the teeth (to obtain the differential segmental movement); force to the lateral segments of the maxilla without their distortion; and expansion of the smaller segment without creating posterior crossbite. Unfortunately, many appliances do not satisfy these functions. A new fan-type expansion appliance has been designed by the authors to solve these problems. This appliance consists of three parts, as follow: an expansion screw; four bands (anchorage); and a joint connecting both buccal segments. The expansion screw is set in a direction tangent to the curve drawn by the intended fan-type movement of the collapsed small segment. The joint converts the expansion force from parallel to an arched direction.