Long-term stability after high-pull headgear combined with fixed appliances: A retrospective cohort study of growing class II patients

Abstract

Background: High-pull headgear with fixed appliances is a common therapeutic plan in class II growing individuals, especially in those with a tendency to hyperdivergence. The stability of this approach has not been adequately assessed in the long-term. The aim of this retrospective study was to assess that long-term stability by means of lateral cephalograms. Seventy-four consecutive patients were included and examined at three time-points: pre-treatment (T1), end of treatment (T2), and at least five years post-treatment (T3).

Results: The average initial age of the sample was 9.3 years (standard deviation, SD: 1.6). At T1, the mean ANB was 5.1 degrees (SD: 1.6), the mean SN-PP 5.6 (SD: 3.0) and the mean MP-PP 28.7 degrees (SD: 4.0). The median follow-up time was 8.6 years with an interquartile range of 2.7. A statistically significant, but of small magnitude increase in the SNA angle was noted at T3 compared to T2 after adjusting for the pre-treatment SNA value (mean difference (MD): 0.75; 95% CI: 0.34, 1.15; P<0.001). The inclination of the palatal plane appeared stable in the post-treatment period, while the MP-PP angle showed scarce evidence of decrease during the post-treatment period after adjusting for sex, pre-treatment SNA and SN-PP angles (MD: -2.29; 95% CI: -2.85, -1.74; P<0.001).

Conclusions: The sagittal position of the maxilla and the inclination of the palatal plane appeared to be stable after treatment with high-pull headgear and fixed appliances in the long-term. Continuous mandibular growth, both sagittaly and vertically, contributed to the stability of class II correction.

Keywords: Class II malocclusion; Fixed orthodontic appliances; High-pull headgear; Retention; Treatment stability.