Class III occlusal schemes and cross bites

• In this type of occlusion the maxillary posterior teeth are crossed over to the mandibular posterior teeth so that the buccal cusps of the maxillary teeth are articulating in the mandibular central fossa instead of the palatal cusps.
• This occlusal relationship could be either unilateral or bilateral depending on the posterior ridge relationship.
• The mesio-distal tooth position is the same as in a Class I (but in all likelihood requiring mandibular incisors of slightly greater width).
• This posterior tooth relationship brings about that the mandibular teeth are always set on the ridge creating a reverse overbite and overjet, thereby preventing cheek biting.
•  The first mandibular premolar in most Class III cross bite cases is set in a near edge to edge position to the maxillary first premolar and canine.  (This crossing point varies depending on the bucco lingual vertical relationship of each particular case.  It often occurs in the mandibular second premolar region.)