EFFECT OF 2 DELIVERY SYSTEMS FOR RECOMBINANT HUMAN BONE MORPHOGENETICPROTEIN-2 ON PERIODONTAL REGENERATION IN-VIVO

Resorbable collagen membranes for guided tissue regeneration in period ontal therapy have shown promise but are not osteoinductive. As recomb inant human bone morphogenetic protein-2 (rhBMP-2) is known to have an affinity for collagen, the use of this osteoinductive agent incorpora ted into a collagen vehicle may act as a suitable carrier to promote p eriodontal regeneration. The aim of this study was to investigate the effects of two different collagen delivery systems for rhBMP-2 in rat periodontal fenestration defects. Using the collagen membrane delivery system, 3 groups of adult Wistar rats which had surgical defects crea ted on the right side of the mandible involving the removal of bone an d exposure of the molar roots were treated with either rhBMP-2 in coll agen membrane (BMPm) (n=12 animals), or collagen membrane only (COLm) (n = 12), or were left untreated(UN) (n=14). Using the collagen gel de livery system, surgical defects were treated with either rhBMP-2 incor porated in a collagen gel carrier (BMPg) (n=5) or had collagen gel onl y (COLg) (n=6). Animals were killed 10 d postoperatively and tissues p rocessed for histology. New bone formation was significantly greater i n BMPg compared with both BMPm and controls (p<0.05). However, new cem entum formation was significantly greater in BMPm (721 +/- 166 mu m(2) , mean +/- SE) compared with COLm, COLg and UN (p <0.02) (190 +/- 44 m u m(2), 327 +/- 114 mu m(2) and 172 +/- 33 mu m(2), respectively) and more than 1.5 times BMPg (451 +/- 158 mu m(2)). In conclusion. both ca rrier systems for rhBMP-2 significantly increased new bone formation c ompared with controls during the early stages of periodontal wound hea ling. However, the more slowly dissolving collagen membrane carrier sy stem for rhBMP-2 produced significantly greater new cementum compared with the collagen gel carrier, suggesting that a more prolonged exposu re of rhBMP-2 is required to increase cementogenesis.