Vertical skeletal and dental changes in earlytreatment of class II malocclusion

Increases in the vertical dimension can be detrimental in certain facial types or unstable in others. By using cephalograms, this study examined the skeletal and dental changes as well as their permanence in a group of children participating in a randomized clinical trial on the timing of Class II orthodontic treatment. Children (mean age, 9.6 years) were assigned to either a headgear/biteplane (n = 94), bionator (n = 86), or observation (n = 82) group. Cephalometric data were obtained from tracings at baseline, after Class I molar was obtained or 2 years after treatment had elapsed, and after 1 year of retention or observation. In general, the skeletal changes, such as total anterior and posterior face height and mandibular plane angle, observed during the active phase of early treatment persisted until the end of phase I. Phase I treatment also produced dental changes, such as molar eruption and tip. With the exception of the eruption of the mandibular molars in the bionator group, these changes could not be maintained until the end of phase I. Whether the subjects were in retention or not had little impact on any of the studied parameters. Mandibular plane angle, pretreatment, and retention had an affect on the mandibular molar tip over the course of the study.