This is a type of equipment used in the treatment of patients with milk and removable bites. A trainer is a kappa (usually silicone) that is worn on both dentitions (double jaw kappa) and controls the ratio of dentitions (or jaws), i.e. the trainer is a positioner. Trainer can be effective. However, more often in complex treatment or, as an alternative, in the absence of the possibility of using biteplates, in a milk or replaceable bite (but not in a permanent bite). As for the correction of uneven teeth. The biteplate "gets" a place for teeth mechanically, using a screw, for example. The trainer does the same "creating the prerequisites" for the normal development of the dentition. It is necessary to clearly understand its capabilities. In addition, the biteplate should be in the mouth round the clock. However, the trainer should be inside an hour a day and at night. The difference is also noticeable.