Skeletal anchorage would offer capabilities heretofore unavailable. They expand the range of biomechanical possibilities with screws, pins or other implant systems anchored to the jaws, so that forces might be applied to produce tooth movement in any direction without detrimental reciprocal forces on the anchor teeth. Orthodontic forces might be applied directly to the jaws through skeletal anchorage1. Intra-oral skeletal anchor units that are predictably stable, relatively noninterfering, biocompatible and comfortable could make appliance design simplified and more efficient. Progress in the...