A prospective cohort study of a clip-on fixed functional appliance.

The aim of this study was to evaluate the effectiveness of a fixed Twin-block appliance by using a study with a prospective cohort design. Thirty-two children were included in the study over a 2-year period. Cephalometric data were analyzed with the Pancherz cephalometric analysis. Study models were analyzed with the PAR index, and the treatment processes were recorded from the patients' records. The results showed that this appliance was effective in correcting Class II malocclusion; the noncompliance rate was only 6%. It can be concluded that this method of treatment might have some advantages over other fixed and removable functional appliances, but this should be tested with randomized trial methodology.