In Situ Tissue Engineering

Abstract

In situ tissue engineering refers to the regeneration of normal tissue, in this case bone, directly at the site that it is required. It is a relatively new and powerful tool that eliminated open bone harvesting from donor sites and therefore the morbidity associated with it.

The principle is the classic tissue engineering triangle of cells, signal, and matrix. In the younger patients (<30 years) and in uncompromised tissue, the cells are derived from resident stem cell and progenitor cells at the recipient site and those in platelet-rich plasma (PRP). The matrix is the cancellous allogeneic bone and the cell adhesion molecules, fibrin, fibronectin, and vitronectin, in PRP. The signal is recombinant human bone morphogenetic protein-2/acellular collagen sponge (rhBMP-2/ACS) at a dose of 0.5 mg/tooth width for ridge augmentation and 1.0 mg/cm length for a continuity defect.

For patients older than 30 years and with larger defects such as post-cancer resections, benign tumor resections, and osteomyelitis, the non-cancer patients with drug-induced osteonecrosis, and the osteoradionecrosis cases, the cellular element is derived from a bone marrow aspirate (BMA) or a bone marrow aspirate concentrate (BMAC). These both contain true stem cells (CD34+) and the osteoprogenitor cells CD44+, CD90+, CD105+, and CD271+ and will be the cellular source of bone regeneration with the same matrix and signal as used with PRP for ridge augmentations.

The time saving, morbidity reduction, less operating time, and less hospital time strongly recommend this scientifically and clinically proven method to regenerate bone in areas of lost bone.