The literature pertaining to mesiodistal reduction of mandibular anterior teeth was reviewed and only occasional references to the subject were found. 7, 11, 17 The latest dental anatomy texts were reviewed to obtain modern findings on enamel substance. 2, 12–14, 18 Enamel spindles and tufts run approximately one-third the distance from the dentinoenamel junction through the enamel, while lamellae run all the way through (Figs. 1, 2, and 3). The matrix of enamel surrounds the enamel rods and prisms and can be considered as extended all the way through the enamel. Spindles, tufts, lamellae, and matrix essentially are organic materials. 12–14 Enamel matures from childhood eruption until adult life by the organic substance of enamel becoming permeated from the external surface inward with calcium salts from the saliva. 4–6 The late literature on caries disclosed that the organic material of enamel undoubtedly plays an important part in the carious process, in many instances being the initiating and penetrating factor in the process. 3–6, 15 The difference between tight contact and loose contact was found to be 0.10 to 0.12 mm. and the difference between tight contact and completely clear contact, 0.23 to 0.25 mm. In stripping, if a separator was not employed, the amount removed was directly related to the thickness of the strip being used, caused by binding against the next tooth as it was being drawn through. If less than 0.10 mm. was to be removed or that amount divided between both teeth making contact, it was necessary to use a separator to permit free handling of the strip. The average thickness of enamel at the contact points in adult mandibular central incisors measured was found to be 0.59 mm., in mandibular lateral incisors, 0.66 mm., and mandibular cuspids, 0.82 mm. No definite correlation was found between tooth size and enamel thickness at the contact points. The largest tooth did not always have the thickest enamel but, generally speaking, the larger teeth had more enamel thickness than the smaller teeth. A step-by-step technique was given for mesiodistal reduction of mandibular anterior teeth. The roughness of enamel after the use of metal strips was demonstrated (Fig. 9), which points to the necessity of polishing with fine cloth strips in order to leave an acceptable surface.