UCSF

Orthodontics is a specialty of dentistry that focuses on the correction of malpositioned teeth and jaws through dentofacial orthopedics. Thus, a critical understanding of tooth movement, retention, and relapse is crucial for clinical practice and treatment advancements for our patients. The foundation of orthodontic tooth movement (OTM) and relapse must be studied at the cellular level, by examining the role of osteocytes. Many studies have explored the mechanisms underlying OTM and relapse but have focused more on the roles of osteoclasts and osteoblasts. Recent studies are now investigating osteocytes and unveiled that these cells are integral in mechanical-sensing in bone. On the molecular level, one of the pathways that is warranting further investigation is TGF-ß signaling in osteocytes with respect to orthodontic tooth movement. Studies showing that osteocytes directly remodel their perilacunar/canalicular matrix suggest that TGF-ß controls bone quality through this remodeling as well. TGF-ß has also been shown to stimulate osteocytes to increase RANKL production, ultimately leading to osteoclastogenesis in long bones. The aim of this study is to determine the extent to which osteocyte-intrinsic TGF-ß signaling in alveolar bone affects orthodontic tooth movement rate and alveolar bone remodeling. We will employ TβRIIocy-/- mice to examine the mechanism of TGF-β signaling in osteocytes. TβRIIocy-/- and control littermates will undergo OTM for 14 days through a spring assembly mesializing the upper left first molar. MicroCT scanning will be used to measure factors such as orthodontic tooth movement rate, bone volume, bone mineral density, alveolar bone height, root length, and root volume. The goal of this project is to analyze osteocyte function during orthodontic tooth movement and understand its mechanism so that we can safely and efficiently move teeth while reducing dental relapse potential afterwards. Thus, we can spark future clinical applications in orthodontic treatment and efficiency.