Changes in soft-tissue profiles after treatment of class II/1 patients with bite-jumping appliances

We performed this study to describe changes in the soft-tissue profile after orthodontic treatment with Trankmann’s bite-jumping appliances. A total of 69 patients thus treated were compared to a control group of 36 age-matched patients based on cephalograms. Statistical analysis included mean values, standard deviations, t-tests, and Pearson’s correlation testing. Highly significant (p<0.001) changes in total profile angle (N’-Ns-Pog’) were observed over the course of treatment. Furthermore, a mildly significant (p<0.05) correlation with SNA angles was noted. Changes in the soft-tissue profile angle (N’-Sn-Pog’) were moderately significant (p<0.001). The profile angles of the upper lip (Sn-SS-Ls) and lower lip (Pog’-Sm-Li) did not reveal significant changes. We observed highly significant (p<0.001) findings in the esthetic line (NsPog’) advancement relative to the Ls and Li landmarks and in increases in lower-face height. Midface heights remained unchanged. Our results indicate that treatment with bite-jumping appliances results in increased facial convexity, advancement of the esthetic line, and increased lower-face height. The cumulative effects of growth and treatment do not, however, appear pronounced enough to result in a preference for or against treatment with a bite-jumping appliance.