Mental index, mandibular cortical index and panoramic mandibular index (Figure 1); C2—the endosteal margin has semi- is clearly porous, severely eroded cortex (Figure lunar defects (lacunar resorption) or endosteal 3). The thickness of the mandibular cortex was cortical residues on one or both sides (Figure 2), divided by the distance between the mental fore- mild to moderate cortex erosion; C3—the cortical men and the inferior mandibular cortex to obtain layer forms heavy endosteal cortical residues and the PMI.15 Figure 1. Example of category C1 of the mandibular cortex index. Figure 2. Example of category C2 of the mandibular cortex index. 62 Figure 3. Example of category C3 of the mandibular cortex index. European Journal of Dentistry