Planas direct tracks for early crossbite correction.

Prof. Pedro Planas of Spain initially developed PDTs,1 and Simoes11 adapted them for early prevention of anterior or posterior crossbite. PDTs should be used in the deciduous dentition only, as they cover the occlusal surfaces of the molars, resulting in a flat posterior occlusion until the molars are exfoliated. PDTs can be built in the laboratory using an indirect technique. A wax bite registration should be taken in an edge-to-edge incisor relationship. The casts are then mounted on an articulator; a separate articulator is recommended to facilitate working with each cast individually. If selective grinding is required, it should be performed on the casts before the tracks are constructed and then reproduced in the mouth. The tracks are built out of self-curing acrylic, first on the lower cast (Fig. 1). For a posterior crossbite, the inclined plane is contoured from lingual to buccal on the lower deciduous molars of the crossbite side only (Fig. 2). For an