1. Clinical measurement of force systems upon activation of transpalatal arch in the treatment of unilateral crossbite.
- Author
-
Yoshida N, Koga Y, Jost-Brinkmann PG, and Kobayashi K
- Subjects
- Algorithms, Biomechanical Phenomena, Humans, Models, Biological, Molar physiopathology, Stress, Mechanical, Tooth Movement Techniques, Tooth Root physiopathology, Torque, Malocclusion therapy, Palatal Expansion Technique
- Abstract
Objectives: in this study, forces and moments acting on the molars were theoretically determined by means of small-deflection analysis when an asymmetric third-order activation of the TPA was carried out., Materials and Methods: the transpalatal arch (TPA) is used to correct unilateral crossbites through the application of buccal root torque to the anchorage molar and lingual root torque to the contralateral molar in crossbite, combined with expansion. Unfortunately, the complex force systems created at the molars upon activation of the TPA cannot be easily estimated., Results: our computations revealed that the vertical forces developed on the molars when both ends of the TPA are inserted into the lingual sheaths (two-couple system) is four-times greater than those when only one end is tied to the lingual sheath as a single-point contact (one-couple system)., Conclusions: we propose a method of clinical estimation of the force system in a two-couple system by directly measuring the vertical force produced by the one-couple system.
- Published
- 2003