Application of the orthodontic measurement and simulation system (OMSS) in orthodontics.
An orthodontic measurement and simulation system (OMSS) is introduced. The major component of the system consists of two force-moment sensors capable of measuring forces and moments in all three planes of space simultaneously. The two sensors are mounted on motor-driven positioning tables with full three-dimensional mobility. All mechanical components are built in a temperature-controlled chamber. A control programme executed by a personal computer performs various types of measurement which can be classified as absolute measurements (e.g. force-deflection diagrams) and simulations of orthodontic tooth movement. By using the OMSS any orthodontic problem at the level of a two-tooth model can be analysed statically and dynamically. Besides other applications, the study evaluates three mechanical systems available for uprighting molars, namely a straight wire, a conventional uprighting spring, and a modified Burstone uprighting spring. It was found that the force systems produced by the straight wire and by the conventional uprighting spring showed a severe extrusive force component which may lead to occlusal trauma. The uprighting performance of the straight wire was inadequate. The conventional uprighting spring produced a large uprighting moment (17.8 Nmm), but also a strong lingual tipping moment (1.5 Nmm). The modified Burstone loop showed the best static and dynamic performance. It produced a force system with substantial uprighting moments in both the sagittal (11.6 Nmm) and frontal plane (4.2 Nmm). A slight intrusive force (0.09 N) might prevent the development of occlusal trauma during treatment. However, concern should be addressed to the fact that intra-oral adjustment of this uprighting spring is difficult because of its high susceptibility to minor modifications of its geometry.
Department of Orthodontics, University of Bonn, Germany.
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Drescher
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Bourauel
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Thier
D001696:Biomechanical Phenomena; D003198:Computer Simulation; D003199:Computer Systems; D004867:Equipment Design; D006801:Humans; D008954:Models, Biological; D008963:Molar / Q000033:anatomy & histology / Q000502:physiology*; D009967:Orthodontic Appliances; D009969:Orthodontic Wires; D012399:Rotation; D013314:Stress, Mechanical; D014087:Tooth Movement Techniques / Q000295:instrumentation