Consequently, when mandibular anterior teeth are present, the arch width from distal-of-canine to distalof-canine can be measured, and this measurement times 1.3 equals the required arch width of maxillary anterior teeth to produce a Class I canine relationship. To allow for intentional disclusion of the maxillary anterior teeth arrangement, the ratio can be slightly modified. A ratio of 1.38 will usually yield the desired result. There is an acceptable range of minimum and maximum for the mesiodistal width of the selected maxillary anterior teeth mold.