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BACKGROUND:Now experimental and clinical research on suitable bone substitutes for alveolar bone defects after dental implantation is an issue of concern.OBJECTIVE:To study the therapeutic effect of titanium core/bone morphogenetic protein (BMP) composite material on alveolar bone defects after immediate implant placement.METHODS:Twenty-four New Zealand rabbits were randomly assigned into normal group (no intervention),experimental group or control group.Animal models of bone femoral greater trochanter defect were made in the experimental and control groups.Dental implant and titanium core/BMP composite material were implanted in the experimental group,while dental implant and titanium core were implanted in the control group.Percentage of CD4+,CD8+ T lymphocytes,natural killer cell activity and interleukin 2 level were detected at postoperative 4 weeks;bone mineral density and osteogenesis around the implant were detected at postoperative 16 weeks through X-ray and histological examinations.RESULTS AND CONCLUSION:X-ray results showed that the bone mineral density in the experimental group was significantly higher than that in the control group (P ＜ 0.05).Histological results showed that in the experimental group,different degrees of cell lysis around the composite,more bone cells and bone matrices were found,implant-bone osseointegration formed well,and red-dyed mature bone tissues were detective inside the implant.Compared with the experimental group,lower number of bone cells and fibrocytes were found in the control group.Additionally,the percentage of CD4+ and CD8+ T lymphocytes,natural killer cell activity and interleukin 2 level in the experimental group were significantly lower than those in the control group (P ＜ 0.05).To conclude,the titanium core/BMP composite material can effectively repair alveolar bone defects after immediate implant placement to guide the growth of bone cells.
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BACKGROUND:Nerve growth factor has been shown to play an important role in bone healing, but little is reported on the effect of growth factor composite scaffolds via the immediate implantation in the repair of canine bone defects. OBJECTIVE:To analyze the effect of nerve growth factor composite scaffolds via the immediate implantation for the repair of canine bone defects. METHODS:Nerve growth factor composited strontium apatite scaffolds were prepared. Canine mandibular defect models were established and divided into three groups, fol owed by implanted with composite scaffold (experimental group), strontium apatite (positive control group), or nothing (blank control group). The three-dimensional CT reconstruction and hematoxylin-eosin staining of canine mandibular bone defects were observed. RESULTS AND CONCLUSION:In the blank control group, there were few new bones surrounding bone defect. Trabecular bones spread from the defect center to the surrounding tissues in the experimental and positive control groups. The bone density, volume, thickness, and implant-bone contact were significantly increased, while the trabecular separation was significantly decreased in the experimental group compared with the positive control and blank control groups (P<0.05), and al above indicators in the positive contro group were significantly higher than those in the blank control group (P<0.05). Hematoxylin-eosin staining showed that in the experimental group, there were a large number of new bones that contacted with the surrounding bones closely, and trabecular bones arranged regularly. In the positive control group, newborn osteoid, trabeculare, and a smal amount of debris were found. In the blank control group, few new bones were connected with the surrounding bones untightly and trabecular bone arranged irregularly. These results indicate that the nerve growth factor composite scaffold can promote the bone regeneration in the canine bone defects after immediate implantation.
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Objective:To evaluate the effects of the flowable resin used as pit and fissure sealant using different etching adhesive systems.Methods:60 caries-free extracted human premolars were randomly divided into 4 groups(n =1 5)and treated by Gluma, NT and 3M-Z350 flowable resin(group A);Clearifil SE Bond adhesive and 3M-Z350 flowable resin(group B),phosphoric acid etching,3M-Z350 flowable resin and phosphoric acid etching(group C)and 3Mconcise sealant(group D)respectively.After pro-cessing the tooth surface the pit and fissue of 1 0 sample in each group were sealed.The microleakage was measured by 1 % methyl-ene blue staining(n =8).The material-enamel interface was observed by SEM(n =2).The shear bond strength of the column-shaped samples with the diameter and the height of 3 mm(n =5)on the mesial or dental surface was examined by a test machine. The sealant cartridges and flowable resin cartridges with the diameter and height of 4 mm were used for the crushing strength exami-nation(n =1 0).Results:There was no significant difference in the microleakage among the 4 groups.SEMobservation showed that the resin tags of group A were long and dense and the resin tags of group B were short and sparse,bubbles and cracks were found on the local site in group A and B.The resin tags of group C were long and thin,but combined with tooth tightly;the resin tags of group D were short and dense;the penetration was poor at the bottom of the fissures in the 4 groups.The shear bond strength of Group A was the highest(P 0.05).The compressive strength of flowable resin groups was higher than that of fissure seal-ant group(P <0.05).Conclusion:The shear bond strength and compressive strength of all-etching bonding system combined with flowable resin is superior to that of self-etching bonding system combined with flowable resin and the traditional sealant.Using Prime&Bond NT bond after acid etching may improve the shear bonding strength.
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Objective To study the expressions of fragile histidine triad (FHIT) and hMLH_1 in oral squamous cell carcinoma (OSCC) and their correlativity. Methods Immunohistochemistry was used to detect the expressions of FHIT and hMLH_1 in 69 OSCC and 40 normal oral mucosa. The data was analyzed by Chi-square test. Results The positive rate of FHIT and hMLH_1 in OSCC (46.4% and 47.8%) was lower than that in normal oral mucosa (77.5% and 77.5%), with statistically significant difference (P