RESUMO
BACKGROUND: To repair bone defect, histocompatibility, growing characteristics, biodegradation and repairing mechanism of nanometer need to be further studied in clinic. OBJECTIVE: To observe the growing characteristics and histocompatibility of nano-hydroxyapatite (Nano-HA) for repairing jaw defect of rabbits.DESIGN: Randomized grouping animal study.SETTING: Beijing Jishuitan Hospital and Stomatology College of Jiamusi University.MATERIALS: A total of 24 New Zealand rabbits, either gender, weighing 2.5-3.5 kg, were provided by Animal Experimental Center of Jiamusi University. The animal experiment had got confirmed consent from local ethic committee. Nano-HA was provided by Material Engineering College of Jiamusi University and dealt with routine hyperthermia/hypertension sterilization. In addition, hydroxyapatite was provided by Wuhan Industry University, and the diameter was 1.0-2.0 μm.METHODS: The experiment was carried out in the Experimental Animal Center of Jiamusi University from November 2001 to May 2006. All rabbits were randomly divided into experimental group and control group with 12 in each group. Bone defect in the diameter of 1.0 cm was produced on body of mandible. Nano-HA was used to repair the bone defect of rabbits in the experimental group, while hydroxyapatite was used to repair the bone defect of rabbits in the control group. At 1, 4, 8 and 12 weeks after operation, all rabbits were sacrificed. In addition, medical imaging analysis system was used to analyze generative quantity of tissue in the two groups; meanwhile, histological quality and quantity were also analyzed so as to observe histocompatibility and newborn osteogenesis. MAIN OUTCOME MEASURES: Histocompatibility and newborn osteogenesis.RESULTS: With the time passing by, the amount of repairing materials was decreased because of the combination with newborn tissue into bone in bone defect-repaired region in the experimental group. When it was closed to normal bone, the amount was stable. However, bony callus was not able to grow in materials in the control group. Results of correlation analysis demonstrated that materials were negatively straight-line correlation with newborn bone (r = -0.912 0, P < 0.01). During the repairing procedure of bone defect, newborn bone was closely correlative with Nano-HA; while, with the increase of newborn bone, the amount of repairing materials was decreased because of the combination with newborn tissue into bone.CONCLUSION: Nano-HA can combine with newborn bone tissue so as to rapidly generate bone, while it has an excellent biocompatibility.
RESUMO
A total of 184 teeth obtained from 102 cases(27 males and 75 females aged 17-64 years)were selected from Department of Tooth and Dental Pulp.DalJan Stomatology Hospital from June to Septembet 2007.All the teeth with deep caries which resulted from caries showed no pulp.Ninety-two teeth obtained from 54 cases were regarded as Vitrebond group which were used by light-cured glass to cover pulp;while,the other 92 teeth obtained from 48 cases were regarded as dycal group which were cured by dycal calcium hydroxide.Finally,3MZ250 resin was used in this study.A half-year following up showed that the filling shed and loose were observed in the Vitrebond group(n=1)and the dycal group(n=3)(P>0.05).There were significant differenoe in color between Vitrebond group(n=1)and dycal group(n=8)(P<0.05),suggesting 3M Vitrebond light-cured glass Was superior to dycal calcium hydroxide in decreasing dental pulp stimulation and improving dental appearance.