ment of Orthodontics and Dentofacial Orthopedics and Department of Oral Biology, School of Dentistry, University of Missouri-Kansas City. To deliver the optimal force is an important topic in the orthodontic field. However, the speed of tooth movement is highly variable between individuals for the same applied force/area (stress) and may be related to other factors, such as stage of development, bone quality, and genetics of the individual. Until now, no study has focused on the relationship between strain and alveolar bone remodeling. And no study has focused on the relationship between osteocyte apoptosis and strain in alveolar bone. If alveolar bone remodeling is correlated with certain levels of strain, and strain can be calculated based on loading and bone properties, future orthodontists may customize optimal orthodontic forces for each patient. The hypotheses of the current application are that: different levels of strain may lead to different biological responses in alveolar bone, and high strain in alveolar bone leads to increased osteocyte apoptosis. We will develop the device to deliver loads through mandibular molars in vivo to an anesthetized mouse. Specifically we will study the following biological responses to mechanical loading. Data from this project is expected to provide useful information for future customization of the optimal orthodontic force for clinical patients. The support from American Association of Orthodontists Foundation will be used to generate preliminary data to apply for future funding from NIH.