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FIGURE 7.2 PCs 1 6(A F) of the maxillary dentition in frontal and occlusal views (see Figure 7.1 ). The data
for the PC axis variation are shown as floating gray crosses. The average dentition over the entire set is shown as
a series of black dots connected by solid lines along the incisal edges. The crosses indicate the pattern of differ-
ences for specimens with positive scores along the axis; specimens with negative scores would have the reversed
pattern. It should be noted that the data shown in Figures 7.2 and 7.3 are three-dimensional in nature and that
rotation in three-dimensional space permits a better understanding of the shape variance.
of variance present in the vertical direction in the human dentition and the impact of this
variance on the resultant bitemarks. PLS results are shown only in occlusal view. The first
11 SAs were judged to be significant based on permutation test, but the first four explain a
total of 81.9% of the covariation. Thus, the remaining seven axes are statistically signifi-
cant, but explain little of the covariation.
Clearly identifiable patterns emerge from both PCA and PLS ( Tables 7.1 and 7.2 ), with
the predominant feature in both being the contrast between relatively wide versus rela-
tively narrow arches. Not surprisingly, these show a strong covariance between upper and
lower dentitions. The second PC and SA are also highly similar, showing the relative
displacement of the central and lateral incisors. Because this sample was obtained from
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