Influence of particle size of autogenous bone grafts on the early stages of bone regeneration: a histologic and stereologic study in rabbit calvarium.

PURPOSE The aim of this study was to investigate the influence of particle size of autogenous bone grafts on the early stages of bone regeneration. MATERIALS AND METHODS Bicortical skull bone defects were prepared in 15 rabbits (4 in each rabbit). Two defects were filled at random with either small (0.5 to 2 mm3) or large (10 mm3) autogenous bone particles. In addition, 1 defect was left unfilled (control defect). All defects were covered bicortically by expanded polytetrafluoroethylene membranes. The animals were divided randomly into 3 groups and sacrificed after 1, 2, and 4 weeks, respectively. Histologic and stereologic evaluations were performed after the sections were blinded. RESULTS No significant differences in total vessel surface area could be identified among the 3 groups. The total volume of newly formed bone in defects with small particles was larger and more mature compared to defects with large particles after 2 and 4 weeks. Furthermore, the resorption of small particles was more pronounced after 4 weeks, documenting a higher level of bone substitution compared to large particles. DISCUSSION The early stages of bone regeneration were influenced by the particle site of autogenous bone grafts. CONCLUSION The present study indicated that particles of 0.5 to 2 mm3 in size should be preferred to particles of 10 mm3 in size for bone grafting.