Considerable variations in the relative sizes of the two teeth may be seen, because the second premolar does not appear true to form as often as does the first premolar (Table 9-2). The maxillary second premolar may have a crown that is noticeably smaller cervico-occlusally and also mesiodistally; however, it may also be larger in those dimensions. Usually the root of the second premolar is as long as, if not a millimeter or so longer than, that of the first premolar. The two teeth have about the same dimensions on the average, except for the tendency toward greater length of the second premolar root. Ten specimens with uncommon variations are shown in Figure 9-25