Class II division 1: an evidence-based review of management and treatment timing in the growing patient

Class II division 1 is an incisal classification of malocclusion where the incisal edge of the mandibular incisors lie posterior to the cingulum plateau of the maxillary incisors with normal or proclined maxillary incisors (British Standards Index, 1983). There is always an associated increase in overjet (Figure 1). This malocclusion is common, with an estimated prevalence of 15–20%,¹ although there is racial variation, with Class II division 1 more common in Caucasian than Latin American, Middle Eastern and Asian populations, and lowest in Black racial groups.²

A number of genetic and environmental factors may contribute to a Class II division 1 malocclusion:

A number of benefits have been associated with orthodontic treatment including a reduction in the susceptibility to caries, periodontal disease and temporomandibular joint dysfunction, whilst also improving speech and masticatory function. However, the supporting evidence is equivocal.^3,4 It may be assumed that correction of an increased overjet will potentially reduce the risk of trauma, as it has been shown that individuals with an overjet greater than 3mm are twice as likely to suffer injury to their upper incisors.⁵ The meta-analysis undertaken in a recent Cochrane review found that ‘early orthodontic treatment for children with prominent upper front teeth is more effective in reducing the incidence of incisal trauma than providing one course of orthodontic treatment when the child is in early adolescence’.²