Functional efficacy. Two questions will be addressed under functional efficacy: (1) does the device alter bruxing activity, and (2) how do the teeth and device hold up under bruxing activity. Some of the technology used for compliance assessment, above, can be used here. Gold standard methods for evaluating bruxing activity rely on polysomnography (PSG) and EMG activity; therefore, it these technologies will be used as well. To address the second question, how do the teeth hold up, 3-D laser scanning technology will be developed and used to measure changes in macroscopic tooth structure, and confocal microscopy and scale-sensitive fractal analysis will be assessed for utiliity in diagnosing microwear.