Artificial posterior teeth have been evaluated as units opposing each other, which is in contrast to the consideration of individual tooth form. 1. Mandibular movements may be separated into masticatory and nonmasticatory components. Tooth form and arrangement must conform to these movements, the nonanatomic tooth being the more suitable. 2. Pressures on the teeth may create resultant or horizontal stresses which must be controlled. Forces set up during nonmasticatory movements can be better controlled by using nonanatomic teeth arranged on an anatomic articulator. The stresses occurring during masticatory movements cannot be controlled in the same manner since food between the teeth prevents occlusal balance. Flat teeth arranged so that force is directed lingual to lower ridge crest give better control of stress. 3. The “natural” arrangement of teeth as specified by Monson does not take into account all the known tooth arrangements and does not produce the maximum degree of stability in dentures. The anti-Monson arrangement, combined with nonanatomic teeth, is preferable. 4. Nonanatomic teeth, due to lack of cuspal locking, permit the mandible to assume its new position of occlusion with less displacement of the dentures as resorption changes the vertical dimension. The direction of force on these malaligned dentures is more vertical and less horizontal than with cuspal teeth. There is, of course, less trauma to underlying tissues. Cusped teeth do not lock the mandible in position nor do they prevent the dentures from shifting when changes in vertical dimension occur. 5. There is less resorption of the ridge tissue when flat cusped teeth are used. 6. Sears' and Hardy's change of the conventional tooth form might, after further study and improvement, prove to be most beneficial. 7. Esthetics is reduced in the use of nonanatomic teeth, but the comfort is increased. 8. The size of the occlusal surface of the artificial posterior teeth must be in harmony with tissue tolerance to avoid tissue destruction. 9. Nonanatomic teeth are indicated for high, well-developed ridges as well as the low, flat ridges.