Figure 2. Means and 95% confidence intervals for the directions of the axes of maximum stiffness for edentulous mandibles (N = 10). The direction of maximum stiffness varies regionally in orientation and in the amount of variability. The central line in each circle indicates the direction of maximum stiffness (D₃). The lines on each side of the central line represent the 95% confidence intervals. Sites with no lines lack significant orientation. Shading indicates a difference between edentulous and dentate mandibles, which is significant at p < 0.05 (no mark in upper right of circle), or approaches significance at p < 0.10 (solid dot in the upper right of the circle). An inverted solid triangle () indicates a significant difference between facial and lingual cortices.