Abstract: A pattern for the construction of orthodontic appliances such as arch wires and retainers and positioners is made by three measurements of an individual's mouth: (1) the sum of the width of the mandibular six anterior teeth; (2) the width of the mandibular arch at the distal of the cuspids; and (3) the width of the arch at the mesio buccal cusp of the lower six year molars. The average measurement from the cuspid to the mesio buccal cusp of the mandibular six year molar is 18 mm and is used as a constant. From these measurements, a circular arc is formed between the cuspid width with the length of the arc equal to the sum of the width of the mandibular six anterior teeth. The pattern extends back for 18 mm between the cupsid width and the molar width and from there the line extends back at a angle. Since each of the measurements will vary, there will be a great but limited number of each measurement and, therefore, a limited combination of these measurements.