Rapid correction of a simple one-tooth anterior cross bite due to an over-retained primary incisor: clinical report.

Where a permanent anterior tooth cross bite results from over-retention o[ z~ primary incisor, a rapid correction method may prove successlrul. When the over-retained primary incisor is extracted, the permanent successor in cross bite is tipped into the extraction site, correcting the cross bite. Moyers defines a simple anterior tooth cross bite as a dental malocclusion resulting from the abnormal axial inclination of one or more maxillary teeth. I Simple anterior tooth cross bites are termed dental malocclusions chiefly to separate them from the skeletal-type cross bite malocclusions which they can resemble closely. An accurate differential diagnosis to separate the skeletalfrom the dental-type cross bite is key to successful treatment for, as Moyers notes, only the simple or dental-type cross bite can be corrected by tipping the teeth labially to bring them into normal alignment. Lee discusses the diagnostic criteria for separating the dental from the skeletal anterior cross bites. 2 Dental-type anterior cross bites usually exist in those patients where: 1. The molars and cuspids are in a Class I relationship 2. The cross bite involves only one or two teeth 3. The profile of the patient is generally normal and the same when the mandible is at rest 4. The teeth are occluded and the tooth or teeth involved in the cross bite exhibit only an abnormal lingual axial inclination usually in the presence of a causative factor. A variety of factors have been reported to cause the abnormal axial inclination of the teeth in dental-type anterior cross bites. McDonald iscusses three of these in his text. 3 They include a labially positioned supernumerary tooth, inadequate arch length, or a traumatic injury that displaces the permanent tooth bud. An injury also can affect the permanent tooth’s position when it causes delayed exfoliation of the primary tooth. A traumatic injury can cause the pulp of the primary tooth to become nonvital or to undergo calcific degeneration. In these cases the primary tooth does not resorb normally and acts as a foreign body causing, as in the other instances, displacement of the permanent incisor and eruption into cross bite. There are many approaches to the treatment of a simple single tooth anterior cross bite. Treatment choice depends on several factors; Lee outlines five factors to consider before selecting a treatment approach: 1. Adequate space to reposition the tooth in the arch 2. Sufficient overbite to hold the tooth in position following correction 3. An apical position of the tooth in cross bite that is the same as it would be if the tooth was in normal occlusion 4. A Class I occlusion. The following treatments for an anterior cross bite have been reported. They include: tongue blade therapy, inclined planes, a reverse stainless steel crown, and removable and fixed appliances. 3-s Some treatments depend heavily on cooperation of parent and child. In selected cases, when a cross bite results from overretention of a primary incisor, rapid correction may be possible. When the over-retained primary tooth is extracted, the permanent tooth in cross bite is tipped into the extraction site, correcting the cross bite.