AbstractMEASUREMENT OF FORCES AND MOMENTS IN THREE-DIMENSIONAL ARCHWIRESBy Dwight V. Buelow, D.D.S.A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University.Virginia Commonwealth University, 2003Major Director: Steven J. Lindauer, D.M.D., M.D.Sc.Chairman and Professor, Department of OrthodonticsOrthodontic tooth movement occurs in response to the application of controlled mechanical force systems. The purpose of this study was to improve understanding of those force systems by evaluating differences between the resultants of two-dimensional and three-dimensional orthodontic appliance activations. An in-vitro model was constructed and three force-moment gauges were used to measure the forces and moments produced. Comparisons were made between two-dimensional and three-dimensional v-bend activations. Measurements were made with both edgewise and ribbonwise wire orientations. Locations of v-bends resulting in zero moment at the incisor were found to be closer to the molar than the anticipated 1/3 of the distance from molar to incisor, for both two-dimensional and three-dimensional wires. For two-dimensional wires, this v-bend location was found to be approximately ¼, while for three-dimensional wires it was even closer to the molar. Ribbonwise wires, both two-dimensional and three-dimensional, produced forces and moments of greater magnitude than their edgewise counterparts. Further research is required to explain the differences between anticipated and actual results, and to develop more accurate means of modeling orthodontic force systems.