Efficacy of Newly Synthesized-Absorbable Carbonate Apatite in Palatal rat Healing

Objectives: Complete restoration of alveolar bone is essential for healing and regeneration of periodontal tissue. Therefore, grafting material needs osteo-inductive capacities to achieve ideal periodontal healing after periodontal surgery. Clinical success (new bone formation) should be largely dependent on interactions between implant and surrounding biological environment. In this study, we aimed to evaluate osteo-inductive and biocompatible capacities of newly synthesized-hydroxy carbonate apatite powder (CA) in rat palatal wound healing compared to hydroxyapatite (HA) well-used clinically, because CA is absorbable and mimics chemical composition of bone. Methods: Newly developed CA and commercialized HA (Boneject®, KOKEN) were implanted into bone defects created surgically in palate of rats (male, 13 weeks, SD rat). Two and three weeks after application of the material, the rats were sacrificed and histological examination was performed. For in vitro evaluation of CA, in MC3T3-E1 osteoblastic cells, we measured 1) cell proliferative activity using MTT assay, 2) alkaline phosphatase (ALP) activity using fluorometric assay. The cells were cultured with CA or HA (0-100 µg/ml) for 24 hr to examine cell proliferative activity, and for 10 days to examine ALP activity. Results: We observed newly formed bone in bone defect area in both CA and HA group after 3 weeks. In vitro study, decreased tendency was observed in the proliferative activity of MC3T3-E1 ostaoblasts stimulated by CA. There were no significant differences between CA and HA in ALP activity. These results indicate that CA may have osteo-inductive ability same as HA. Conclusion: Our findings show CA could be useful as a biodegradable bone substitution materia