[The principles of two-teeth-mechanics in straight-wire-technique].

Application of straight-wire-technique leads to expression of complicated biomechanical systems. If these--according to Burstone--are subdivided into simple couples of teeth, it is possible to determine the moments and forces acting on one side of a tooth. However the significant factor for clinical tooth movement are the resulting forces and moments. These can be computed by adding the vectors of the forces and moments acting on both sides of a tooth. Consequently the movement of a single tooth results from the geometry of three teeth. This can be simulated by the superimposition of two systems of two teeth.