Class II Division 1 in New Dimension: Role of Posterior Transverse Interarch Discrepancy in Class II Division 1 Malocclusion During the Mixed Dentition Period

Posterior transverse discrepancy as seen in some cases of Class II Division 1 malocclusion in mixed dentition period can be related to typical skeletofacial characteristics. These features when studied early in the mixed dentition period give a clear view of the desired appropriate treatment plan in a particular case. The purpose of this study was to establish a simple method to determine the posterior (intermolar) transverse discrepancy and craniofacial skeletal features between the dental arches during the mixed dentition in a sample of Class II Division 1 patients to provide diagnostic and therapeutic guidance in the early approach. A sample of 60 Class II Division 1 patients in mixed dention that were divided into 30 Class II Division 1 patients with posterior transverse interarch discrepancy {Class II (I) PTID group} and 30 Class II Division 1 patients without posterior transverse interarch discrepancy {Class II (I) NPTID group}. Thirty Class I subjects in mixed dentition were included as control. The skeletal features of the Class II group without PTID are those of the skeletal Class II associated with 'anatomic' mandibular retrusion (due to a micrognathic mandible) and those of the Class II group with PTID as skeletal Class II associated with only a 'functional' mandibular retrusion (due to a posteriorly displaced mandible of normal size). This study confirmed the role of occlusion in the control of maxillomandibular skeletal relationships.The treatment strategies could be planned on the basis of the transverse component of Class II Division 1 groups in the mixed dentition period.