INDUCTION OF BONE BY A DEMINERALIZED BONE-MATRIX GEL - A STUDY IN A RAT FEMORAL DEFECT MODEL

Demineralized bone matrix contains osteoinductive factors and stimulat es filling of gaps and defects with bone; however, it is difficult to handle by itself and various preparations have been tested. Deminerali zed bone matrix with a gel consistency now is available for clinical u se. We studied? in a femoral segment defect in the rat, the effects of rat demineralized bone matrix gel with and without a ceramic substrat um. This preparation is analogous to the human demineralized bone matr ix in the same carrier: used clinically for humans. One hundred adult male Fischer rats were divided into 10 experimental groups. Independen t variables included the presence or absence of hydroxyapatite ceramic cylinders, the presence of demineralized bone matrix in carrier or ca rrier alone (glycerol), and the duration of observation (1, 2, and 4 m onths). Defects filled with the gel alone had significantly higher rad iographic scores for host-graft union at 4 months compared with cerami c with the gel, ceramic alone, or carrier alone. Demineralized bone ma trix gel significantly increased the total histologic score for host-g raft union, whether ceramic was present or not, and a three-way intera ction occurred among ceramic, the gel, and time. Demineralized bone ma trix gel was an effective inducer of bone formation in this model. An additional substratum was not required; in fact, significantly more bo ne was formed in the absence of the ceramic cylinder. Neither the gel nor the ceramic were impediments to revascularization of the defect. H ost-graft union was enhanced by demineralized bone matrix gel but not by the ceramic cylinder.