Date of Completion

8-24-2011

Embargo Period

9-8-2012

Open Access

Open Access

Abstract

Abstract

Understanding the biomechanical factors in orthodontics is important in order to improve the overall effectiveness of actual clinical treatment. An accurate method to study the threedimensional (3D) force systems and the resulting movements of teeth during orthodontic treatment is needed along with the understanding of the material properties of any orthodontic wire. Until recently, most of the orthodontic biomechanics literature was limited to twodimensional experimental studies. Recent advances in threedimensional computer modeling have also been developed but have been limited to the manual control of tooth movement. Overall, there is very little published evidence in the literature on the measurement and analysis of threedimensional orthodontic force systems.

The purpose of this thesis was to develop a costeffective orthodontic wire tester that is capable of threedimensional measurements and analyses of orthodontic force systems. A device was developed that can perform standardized three point bending tests on any orthodontic wire according to the International (ISO 15841) and American (ANSI Specification No. 32) standards. Jacobian transformations were validated and were used to measure the force/torque values at precise locations using two threedimensional force/torque sensors and a stepper motor in a temperature controlled environment. The measurement error of both force/torque sensors was found to be 0.5% or less after extensive verification. As an application, the load/displacement curves for six different sizes of NickelTitanium (NiTi) wires were generated using a three bending test protocol, which was developed in LabVIEW. To further validate the efficacy of the device, the unloaded bending force values were compared with the manufacturer’s specifications and the results showed a high degree of correlation. A comparative study between the standardized three point bending test of ISO and ANSI was also performed and demonstrated good measurement correlation between these standards.

The successful development of the orthodontic wire tester, including its computer protocols, will allow orthodontists to determine, with great accuracy, the forces and torques acting at precise locations on the teeth. It will also allow for future simulation research on new and existing orthodontic clinical applications by orthodontists and biomedical engineers.

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