Demands for esthetic and function have been increased in the patient with alveolar bone loss partially or completely and maxillofacial bone defects. Problems concerned on graft are as follows : Donor site morbidity, limited blood supply from donor tissue, anatomical and structural limitation, too much bone resorption, undesirable immune response , and the possibility of disease transmission. To overcome these problems, the research and development for ideal synthetic bone substitute materials have been done. Recommended synthetic bone substitute materials are Hydroxyapatite(HA), Tricalcium Phosphate, and Bioactive glass ceramics. These materials are absorbed eventually and new bone is formed around them. It is well known that resorption rate is a critical factor for bone regeneration, and osteoconductivity of these materials is limited. We believe that biocompatibility is the key factor for these materials. Recently, Anorganic bovine bone mineral(ABBM) is used clinically, which has the same action on human bone and sinilar composition to human bone. Experiments for this materials is performed by two ways ; One is in Vitro study for the biocompatibility of osteoblastic cell line on the interface of implant materials, the other is in Vivo study in animal. Recently it is necessary to present the compatibility of cultured normal human osteoblastic cell(NHost) in the interface of dental implant material. In the study, we compared the biocompatibility of HA and ABBM through normal human osteoblastic cell culture with cultured normal human osteoblastic cell without material. After we implanted HA and ABBM onto the tibia of rabbit, we observed the bone formation. The obtained results were as follows.
1. Doubling time of both group was approximately 40 hours and a little bit longer than that on the control group. NHost cells had processes perpendicular to HA and ABBM in early stage, making colonies and multilayered cellular arrangement at the 4th week.
2. Although plating efficiency of both group was lower than that on control group, NHost cells seem to be attached to synthetic HA and ABBM.
3. Calcein labelled mineralized nodules near ABBM was slightly bigger in size and more numerous than that of synthetic HA.
4. We observed interconnection of synthetic HA with new bone at the bone loss area at the 4th week and progressive resorption of HA at 8th week. While new bone formation around ABBM was more prominant than that of HA.
5. Polarizing microscopic features showed poorly calcified bone tissue around synthetic HA as a blue color at the 4th week, and almost calcified bone tissue as a yellow and brown color at the 8th week. While it showed almost calcified tissue around ABBM as yellow and brown color at the 4th week, and similar features to adjacent bone tissue at the 8th week.
6. Reflection electron microscopic features showed new bone tissue attached to the implanted materials in both group at the 4th week and new bone tissue around completely the implanted material at the 8th week. While new bone tissue with different contrast around ABBM was more calcified.
7. EPMA showed P deposition of new bone tissue around synthetic HA similar to compact bone after the 4th weeks, but Ca deposition was more increased at the 8th week than at the 4th week. While Ca and P deposition of new bone around ABBM was relatively higher than that of HA less than that of compact bone.
From the aboving results, both groups showed long doubling time and low plathing efficiency compared to control group, but NHosts were tightly attached to HA and ABBM. Calcein labelled nodules in ABBM were formed superior to HA. There were well calcified new bone formation around ABBM, and prominant Ca and P deposition compared to that in synthetic HA, which was less than that of compact bone at the 8th week. It was suggested that although AMMB was superior to that on synthetic HA, both group had the good biocompatibility in this experiment.
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