Based on the National Center for Health Statistics, Class II malocclusions occur in 15-20 percent of U.S. white children ages 6-11. However, there are few systematic, prospective longitudinal studies evaluting the effects of early (phase 1) treatment of this problem and controlling for the growth and maturational factors which may be associated with therapeutic outcome. This investigation will compare the treatment results of two commonly used therapies with differing modes of action on Class II division 1 malocclusion: head gear, and the Frankel functional appliance. The sample of children will consist of eighty white male and female patients selected in mid-to late childhood equally divided, and randomly assigned to the two treatment groups which are subcategorized by severity of malocclusion and skeletal maturity. Data collected will consist of a series of measures made at different time periods. Evaluation of cephalometric data will involve comparison of linear and angular measurements as well as an improved method for detecting growth from superimposition on cranial, maxillary and mandibular bases. Dental casts taken quarterly will be measured for changes during treatment. Detailed growth, maturational and hormonal data will be collected to determine the growth correlates of therapeutic outcome during the treatment period: monthly anthropometric measurements, including a new precise measure of lower limb length; and monthly measurement of the salivary and biannual measurement of the serum concentration of the adrenal androgen, dehydroepiandrosterone sulfate (DHEAS), which has been associated with the mid-growth spurt of childhood. Hypotheses to be evaluated concern those associated with therapeutic outcome of the Frankel appliance on mandibular growth versus the headgear (which directly operates on the maxilla) controlling for skeletal maturity and severity of malocclusion. Other hypotheses involving the effects of variation of growth, maturation and hormonal change during the period of treatment will be evaluated in order to determine more completely the correlates of the efficacy of early treatment.
