In the tooth histogram in Figure 2.17 four distinct materials are visible, denoted by areas of high concentration near the bottom of the histogram.

Turn off the current widgets by clicking the corresponding On checkboxes. The tooth's root is visualized by adding a rectangle over the first material area, as shown in Figure 2.18. To do this, click the Add Rectangle button in the Editor UI.

Figure 2.18. Transfer function highlighting the tooth's root

Now move the rectangle, in turn, to the other material regions to discover the air surrounding the tooth Figure 2.19, the tooth dentin Figure 2.20, and tooth enamel Figure 2.21.

Figure 2.19. The air around the tooth displayed in the viewer

Figure 2.20. Tooth dentin

Figure 2.21. Tooth enamel