Table 1 Indexes analyzed in panoramic radiographs and CBCT images

Mental index

The inferior cortical width of the mandible in the mental foramen region in panoramic radiographs

Panoramic mandibular index

The ratio of the thickness of the mandibular cortex to the distance between the mental foremen and the inferior mandibular cortex in panoramic radiographs

Antegonial index

The cortical width in the region anterior to the gonial at a point identified by extending a line of best fit on the anterior border of mandible in panoramic radiographs

Mandibular cortical index

Mandibular cortical shape distal to the mental foramen in panoramic radiographs:

Class 1 (normal cortex): the endosteal margin of the cortex is even and sharp on both sides.

Class 2 (mildly to moderately eroded cortex): the endosteal margin has semilunar defects (lacunar resorption) or appears to form cortical residues on one or both sides.

Class 3 (severely eroded cortex): the cortical residues are clearly porous on one or both sides.

Trabecular pattern

Pattern of bone trabeculation in the alveolar process area distal to the mental foramen:

Dense: Uniform dense bone trabeculae

Heterogenous: Non-uniform bone trabeculae

Sparse: Uniform porous bone trabecula

Computed tomography mandibular index

The inferior cortical width of the mandible in the mental foramen region in coronal CBCT images

Computed tomography index (inferior)

The ratio of the inferior cortical width to the distance from the inferior margin of the mental foramen to the inferior border of the mandible in coronal CBCT images

Computed tomography index (superior)

The ratio of the inferior cortical width to the distance from the superior margin of the mental foramen to the inferior border of the mandible in coronal CBCT images