The effect of composite graft with deproteinized bovine bone mineral and mineralized solvent-dehydrated bone on exophytic bone formation in rabbit calvarial model

Many studies tried to mix two different kinds of graft materials to combine the uses of their different properties. The aim of this study was to compare the sandwich and simple mixed graft technique using different kinds of graft materials such as deproteinized bovine bone mineral (DBBM) and mineralized solvent-dehydrated bone (MSDB) for mixed and layered grafts in 1-wall exophytic rabbit calvarial model. Twenty New Zealand white rabbits were used. After creating surgical defects at calvarium, titanium reinforced expanded polytetrafluoroethylene (TR e-PTFE) membranes were folded (8 × 5 × 4 mm) and adapted on calvarial defects. Membranes were filled with different materials and methods (no graft, DBBM, MSDB, mixture, layered graft). Four sites were assigned to each group at 8 and 16 weeks respectively. Non-decalcified specimens were prepared and processed for histologic observations. The areas of newly formed bone and residual bone graft material under the membrane were measured. Newly formed bone and graft materials fully filled the membrane space in all grafted groups. The amount of hard tissue was higher in all grafted groups than in control. Although DBBM did not show resorption, MSDB particles showed active absorption. New bone and graft material were uniformly distributed in DBBM and MSDB mixture. However, the composition of graft material was different in layered graft groups. Layered graft of DBBM and MSDB mimicked unique bone structure and provided an appropriate situation for facilitating new bone formation.