Segment concept in arch pattern design.

The forming of arch wires is time consuming and often relies more on artistic interpolation than on scientific method, thus making the basis of orthodontic practice less precise. For years, various methods of designing arch wires have been tried and have been found inadequate. A new approach is advocated. Based on two decades of orthodontic practice and research, it elucidates a segment concept of arch pattern design, using three common reference measurements of the mandibular arch: canine width, molar width, and the sum of the mesiodistal diameters of the six mandibular anterior teeth. Normative data accumulated from 555 dental patients standardize basic measurements and variants. These data permit development of a finite number of arch patterns, adaptable to virtually all patients. A pattern, once selected, may be used as is or individualized to a specific arch form if necessary. Use of the segment concept might permit a much higher degree of clinical efficacy than that obtained with other methods of arch-wire construction.