Biomorphology in BIONJ: Anatomy and Histology

Abstract

The jaw is a horseshoe shaped structure with a concavity that runs dorsally. It presents an anterior and a posterior side. The jaw ramii are quadrilateral expansions that run obliquely upwards and downwards and are compressed on the lateromedial side. The mandible, which has a membranous origin, develops in the first branchial arch, where there is already a cartilaginous skeleton. A relative increase in mechanical stimulation of the jaw results in the marked neodeposition of osseous tissue that is more intensively and rapidly reabsorbed at sites not subjected to pressure. Mandibular bone is subject to normal turnover that is manifested as bone remodeling. While remodelling also involves the gingival tissue, it is unclear whether osteonecrosis of the jaw, such as occurs in patients treated with bisphosphonates, originates in the bone or in the oral mucosa. However, it has been shown that oral mucosal cells with disrupted talin function are unable to form focal adhesions and exhibit spreading defects, whereas cells with vinculin disruption can form focal adhesions but display a reduced ability to spread and an increase in cell motility.