[Tissue engineering for jawbone]

One goal of jawbone reconstruction is to regenerate bone that is strong enough to support dentures or dental implants. Here we describe mandibular reconstructions using bioabsorbable poly (L-lactic acid) (PLLA) mesh and particulate cancellous bone and marrow (PCBM). PLLA mesh is made of monofilaments spun from molecular weight 20.5 x 10(4) that is elongated and woven into mesh. Mandibles of 62 patients with tumors, cysts, or alveolar atrophy were reconstructed with PLLA mesh trays/sheets and PCBM. The operative procedures were as follows: 1) a heat-softened PLLA mesh sheet or tray was cut and bent to conform to the shape and size of the bone defect; 2) PLLA mesh was fixed to the residual bone with stainless steel wire; and 3) the tray was filled with PCBM harvested from the ilium. Clinical evaluations six months after surgery showed that in 35 cases (56.5%) the results were judged to be excellent (bone formation range: beyond 2/3), in 17 cases (27.4%) they were good (bone formation range under 2/3, but re-operation unnecessary), and in 10 cases (16.1%) they were poor (cases not falling into either category above). Long-term observations showed that in 32 cases (80.0%) bone resorption was less than 10% of the regenerated bone. Among the patients wearing early dentures or dental implants, bone resorption was less. There is a good success rate for jawbone reconstruction surgery using PLLA mesh and PCBM, and patients can expect to have mandibles strong enough to support dentures and dental implants. In addition, there is an advantage of regenerating in the donor site as well. However, we need to develop therapies that combine bioactive factors to promote angiogenesis and osteogenesis or hybrid artificial bone for patients with poor regional blood circulation and for elderly patients who have too few osteoprogenitor cells.