Comparison of treatment effects with labial and lingual fixed appliances.

Pretreatment and posttreatment lateral cephalometric radiographs were evaluated for 120 patients--40 from each of three private practices. Twenty patients from each office had been treated with labial fixed appliances and 20 with lingual fixed appliances. There were no significant differences between labial and lingual appliances with respect to the change of any cephalometric measurement during treatment (posttreatment value minus pretreatment value). Differences among patients from the three offices were found only for upper incisor vertical position, and these appeared to reflect differences in treatment objectives rather than in appliances. However, several significant differences were found when changes during treatment were evaluated according to extraction pattern, without reference to the type of appliance used. There was no evidence that the mechanics required with lingual appliances necessarily led to any changes in treatment results, as determined by the cephalometric measurements used in this study.