Structural features of mandibular bone

―morphological and biochemical standpoints―

Abstract

  Human mandibular bone forms at the position of future mental foramen, lateral to Meckel's cartilage, at 7 weeks of gestation. Ossification progresses toward both anterior and posterior position by forming “bone trabeculae” along with blood vessels during fetal period. After birth, mandibular bone formation progresses by adding lamellar bone on the bone surface. Simultaneously, bone modeling, coupled with bone formation and resorption, makes specific shape of mandibular bone. Adult mandibular bone consists “basal bone”, “alveolar part”, and “muscular part”. The shape of mandibular bone is established at the end of growth period. However, the shape of mandibular bone continues to change little by little during lifetime. After loosing teeth, the alveolar part is first resorbed, subsequently the muscular part starts to be resorbed, and consequently the basal bone remains. There is a regular resorption pattern in the process of resorption of alveolar part. The resorption of buccal side precedes that of lingual side, and consequently the arcuate alveolar ridge is formed on the line connecting the center of alveolus.

  Some differences between membrane bone (including mandibular bone) and endochondral bone (including limb bone) have been reported. Adding to the difference of embryonic origin, there are some differences in biochemical characteristics including organic components and tendency of taking resorption between both types of bone.