Studies On Bone Regeneration With Nano-hydroxyapatite/collagen Membrane (nHAC)

An ideal guided bone regeneration (GBR) membrane should meet following requirements: good biocompatibility and safety, the ability of being completely bioresorbed after functional action in order to avoid second stage operation for removing the membrane, adequate mechanical strength to maintain a secluded space for ingrowth of bone tissue, easiness of being operated. The nHAC is composed of natural collagen fibers and nano-hydroxyapatite which has similar micro-composition and characters with the natural bone tissue. It has wonderful biocompatibility and biodegradability. The objective of this experiment is to observe the guided bone regeneration (GBR) in the skull defects of rats and to explore the possibility of exploiting nHAC into medical products.Two 5mm trephined defects are produced in skull of each rat. The defects are treated according to four different ways: 1. covered by nHAC on both defects, 2. covered by COL, 3. covered by PLGA , 4. filled with autogenous blood only as empty control. The defects are studied radio graphically and histologically at 4, 6 and 8 weeks after operation, including globe observation,LM, X-ray, tetracycline labeling, and multi-media computer estimate.As the result, nHAC has good mechanical properties, histological compatibility and can be biodegraded slowly in 6 weeks in vivo. It guides the bone regeneration at the defect region. 8 weeks after operation, the defects covered by nHAC are almost filled by bone. A quantitative radiographic analysis shows that nHAC possesses equivalent effect to COL in quantity of new forming bone (P>0.05) . And there is significantly more bone bridging area in nHAC defects than that in PLGA defects and empty control defects (P<0.05).According to the effects of GBR, nano- hydroxyapatite/collagen membrane (nHAC) could be an ideal GBR material to have mechanical barrier and potential osteoinduction.