Optimization of arch guided tooth movement by the use of uprighting springs.

One of the most important drawbacks of arch guided tooth movement is the friction between bracket and arch wire. In order to reduce frictional forces the application of an uprighting spring is proposed. The influence of uprighting and derotating moments on frictional forces has been measured with a friction testing assembly. Applying appropriate uprighting moments results in a reduction of friction by 73-89 per cent. Derotating moments have only a minor effect on friction. For clinical purposes, the uprighting moment should be 50 per cent of the tipping moment.