In this paper when calculating the volume of cortical tissue in the mandible bone, the author times the thickness of the bone with the surface area of the mandible structure. This did not consider the changing surface area in the outtermost cortical tissue compared to the innermost, which might need to overestimate the volume of the cortical tissue.

Here is the original text :
"Still, knowing that the average thickness of the cortical tissue is Hcort = 1.35 mm and multiplying this value with the surface area of the mandible SA, one can get an estimate of the cortical bone volume: Vcort = Hcort × SA = 55 × 10−6 m3. "

Please share your thoughts and correct me when I'm wrong .
Thanks.