The segmented arch approach to space closure.

The clinical application of frictionless attraction springs using the segmented arch technique is described. Differential space closure is achieved by varying the force system between the anterior and posterior segments. A specially designed force transducer allowed accurate force and moment determination for each spring design. By duplicating predetermined spring geometries, the orthodontist can reproduce the required force system within narrow ranges. The most important considerations in the clinical use of attraction springs are the amount of distal activation, the angulation differential between the anterior and posterior teeth, and the centricity or eccentricity of the loop. Improvements in design have lead to a more efficient, hygienic, and comfortable mechanism for space closure.