The repositioning Nance appliance: a fixed functional appliance and case report

摘要

Functional appliances are primarily orthopaedic tools used to influence the facial skeleton in a growing child. These appliances may be fixed or removable. A fixed functional appliance referred to as the Repositioning Nance Appliance (RNA) was developed and a case report is presented. The RNA is a fixed functional appliance consisting of bands on the upper first molars joined together with a 0.036-inch stainless steel wire that is bent around the anterior contour of the palate. Just lingual to the upper incisors the wire is complemented with an acrylic Nance button, which is modified with a downward and backward incline projection. The labial aspect of this projection is smooth and when the lower incisors come into contact with it, they are directed into an edge-to-edge relation with the upper incisors, brought about by forward positioning of the mandible. This has the net effect of relocating the mandible into a Class I relation. A 14-year-old boy in his late mixed dentition stage of dental development presented with mild crowding, a horizontal growth pattern and a skeletal Class II jaw relation caused by an underdevelopment of the mandible. Treatment was initiated using the RNA and continued for a period of 18 months. This was followed by full fixed appliances for another 12 months and resulted in Class I skeletal and dental relations, a reduced overjet and an improved facial profile. The RNA, if applied correctly is a simple fixed functional appliance that can be used with confidence, comfort and economy to both the patient and orthodontic practitioner.