Histopathological evaluation of effect s nano- hydroxyapatite / zirconia stabilized with yttria in tibia Bone healing of rabbit

The aim of this study was an evaluation of the biological effects of zirconia -stabilized yttria on bone, using an in vivo model: nano–hydroxyapatite powder with zirconia-stabilized yttria and non-treated controls were inserted in rabbit tibia and then histopathologically analyzed. Twenty New Zealand white male rabbits randomly divided into two groups of 10 rabbits in each group. Anesthesia was induced using intramuscular ketamine hydrochloride (20 mg/kg), acepromazine (0.1 mg/kg) and atropine sulfate (0.02 mg/kg), then rabbits connected to anesthetic machine using isoflorane 1%. A cortical hole of 3mm diameter and 8mm depth in each tibia was drilled. In group I, the defect was left empty, where as in group II, the bone defect was packed with nano–hydroxyapatite/zirconia stabilized with yttria. Histological evaluations were performed at four weeks after the implantation. After four weeks the woven bone was formatted in group I. Mixed lamellar and woven bone formation was seen in group II and there was a little inflammation in this group. Foreign body reaction was negative. Bone growth was observed as well as the bone outside the implant and bone inside the implant. Bone lacunas contained osteocyte that demonstrated bone tissue was active and vital. Histopathological changes on two groups were scored and statistical analysis showed that the total average scores in group II were significantly higher than the group I (p