Prediction Model and Examination of Open Vertical Loop Orthodontic Force

摘要

The clearance between two teeth is one of the most clinical manifestations of malocclusion. The open vertical loop is mostly used for the closing and opening of the clearance between two deformed teeth. The shape of the open vertical loop can greatly affect the orthodontic force. At present, the design of the open vertical loop depends entirely on the experience of the orthodontic doctors; this practice is ineffective and may easily hurt patients. To solve these problems, the orthodontic-force prediction model is established to help doctors calculate the orthodontic force generated by the open vertical loop using known parameters, such as the height and the clearance length. The structure of the open vertical loop is analysed, and the theory of the bending deformation of the equivalent beam is used for the analysis of the relationship between the orthodontic force and the effective parameters. The orthodontic-force measuring device of the open vertical loop with a one-dimensional force sensor was designed according to the characteristics of orthodontic force transmission. The orthodontic-force measuring experiments were conducted with open vertical loops of different parameters. Finally, the effective orthodontic-force prediction model of the open vertical loop was established by developing the correction factors in order to eliminate the errors. The average relative error rate of the theoretical value of the orthodontic-force prediction model ranged between 1.25 and 8.34%.