Aim: To discuss the modus operandi of Planas Direct Tracks and the components of crossbites —anterior, posterior, buccal, unilateral or bilateral. Discussion: Modification of mandibular posture is a common finding, especially in unilateral and anterior crossbites, associated with deep bite. Frequently, there will be a modification in condylar position related to the mandibular deviation from the midsagittal plane. In such cases, there are almost always modifications in the activity of the muscles of mastication, lips, cheek, supraand infrahyoid, etc. Mastication tends to be more frequent on the crossbite side. There are also important modifications on the occlusal plane. These aspects—dental, skeletal, neuromuscular —and the temporomandibular joint, mastication, and other functions are discussed. Conclusion: Use of Planas Direct Tracks is an excellent treatment modality for crossbites —anterior, posterior, buccal, unilateral or bilateral—in deciduous and early mixed dentition, which applies natural forces (including growth, dental eruption, mandibular and lingual posture and movements) to normalize the dental relationship and the other components involved. World J Orthod 2002;3:239–249.