Both nickel-titanium (Ni-Ti and beta-titanium (Beta-Ti) arch wires, used in the early and intermediate to later stages of orthodontic treatment, respectively, are attractive wires due to good stiffness and range. However, high frictional coefficients reduce their utility. The proposed Phase II research will demonstrate the clinical efficacy of ion implantation in reducing frictional forces between these arch wires against stainless steel brackets. Phase I research demonstrated, in bench-top tests, that ion implantation provides a substantial reduction in static and kinetic frictional coefficients of Beta-Ti and Ni-Ti arch wires against stainless steel and alumina flats--up to 72% in the case of the static friction for the Beta- Ti/stainless steel couple. In Phase II it will be shown that a similar friction reduction occurs in these wire/bracket material combinations under more realistic testing conditions. Laboratory tests will employ brackets (instead of the flats used in Phase I), which will be tested at three angles in normal whole human saliva. Two clinical trials will measure the efficacy of the improved vs. off-the-shelf appliances. One trial will measure the rate of early alignment (Ni-Ti wires); the other will measure the rate of retraction of incisors (Beta-Ti). If clinical trials reflect, as expected, the improvement which was documented in Phase I, a scale-up study (involving design of custom fixturing apparatus) will be performed to assess transition to production volumes.
