Two-vector mechanics.
The conventional orthodontic appliance is not without its limitations for certain types of tooth movements; in particular, if the appliance cannot access the area to elicit the type of force vector for a particular displacement. Examples of such movements are: space closure by translation, uprighting and intrusion of posterior teeth, intrusion with retraction and lingual root torque of anterior teeth. In this paper we describe a mathematical method to design an appliance system that overcomes these difficulties. This system includes two statically determined elements and allows for highly controlled force vector application point and direction. A clinical case of midline discrepancy is shown to demonstrate the clinical use and utility of this method.
University of Siena, Department of Orthodontics, Policlinico "Le Scotte", Siena, Italy. gfiorelli@libra-ortho.it
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Fiorelli
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Melsen
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Modica
D001696:Biomechanical Phenomena; D006801:Humans; D008310:Malocclusion / Q000628:therapy; D008954:Models, Biological; D009967:Orthodontic Appliances; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D010347:Patient Care Planning; D013314:Stress, Mechanical; D013813:Therapy, Computer-Assisted; D014087:Tooth Movement Techniques / Q000295:instrumentation*