The Invisalign® System consists of a series of clear plastic aligners that are intended to replace conventional wire and bracket technology for many orthodontic cases. Each custom manufactured aligner exerts gentle, continuous forces to move teeth incrementally from their original state to a final, treated state. The aligners are designed to optimally move each tooth at a speed that follows physiologic principles. The purpose of this study is to demonstrate that changing aligners weekly provides similar results to changing aligners every two weeks.