ORTHODONTIC TREATMENT USING ADVANCED ENGINEERING TECHNOLOGIES

Orthodontic treatment aims to correct dental misalignments; however, extended treatment duration and unpredictable force application remain significant clinical challenges. This dissertation presents two integrated engineering solutions to address these limitations: (1) acceleration of orthodontic tooth movement (OTM) through controlled vibrational force (VF), and (2) development of an experimental methodology for validating and optimizing clear aligner therapy (CAT) through force quantification and attachment design analysis. A scientific framework was established for accelerated OTM using intermittent vibrational force (IVF). Animal model experiments systematically evaluated the dose-response relationship of IVF parameters, including peak load, frequency, and application interval. An effective regimen (5 cN at 100 Hz, applied every four days or less) resulted in 63 to 76 percent greater tooth displacement compared to conventional orthodontic force (OF) alone. Micro-CT analysis revealed distinct bone remodeling patterns, with VF alone producing anabolic effects and combined OF and VF leading to synergistic changes in bone mineral density (BMD). Finite element modeling showed a correlation between von Mises stress distributions and BMD changes, supporting potential scalability to larger models and human application. To assess mechanical aspects of CAT, an orthodontic force tester (OFT) was developed. Quantitative analysis demonstrated that attachment geometry and placement significantly affect force systems. Fabrication-related issues such as trimming-induced variability (up to 36 percent deviation in moment) and material relaxation (22.9 percent force decay per cycle) were also identified, highlighting the importance of standardizing aligner production. These findings offer biologically and mechanically informed strategies to improve treatment efficiency and clinical predictability.