Different treatment strategies for monozygotic twins with Class II division 1 malocclusion: 10-year follow-up study

Early-stage growth modification has been demonstrated effective in treating prepubertal patients with Class II division 1 malocclusion. Since monozygotic twins are genetically identical, environmental factors, including oral habits and treatment strategies, may contribute to different treatment outcomes. To date, few reported comparisons of different treatment strategies in monozygotic twins with Class II division 1 malocclusion exist.

In this case report, we compare the effects of different functional appliances and extraction strategies in a pair of prepubertal monozygotic twins. Different compliance and treatment protocols may have different effects on their early changes in facial profile. Customized treatment plans are necessary for optimal treatment outcomes. Both twins achieved favourable improvements in facial profile, and their long-term stability of functional occlusion was also maintained after a ten-year follow-up.

With the outcome of the case, we acknowledged that functional appliance therapy can affect the potentiality of mandibular growth. Individualized protocols should be approached aside from different functional appliances.