Many derangements in the cranio-mandibular relationship can contribute to the etiopathogenesis of tempero-mandibular disorders and postural anomalies. Orthodontists should understand their characteristics in order to prevent their development or correct them if they appear during the course of orthodontic treatment. Occlusal splints for re-positioning the mandible to restore it to a healthy physiological position are an invaluable tool in dealing with this aspect of orthodontic therapy.