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Objective: To study the effects of UV treatment of different zirconia surfaces on the function of MC3T3-E1 osteoblasts. Methods: Disks of zirconia-based materials with smooth(S) and rough(R) surfaces were treated and with and without UV light(15 W) for 48 h,respectively. MC3T3-E1 cells were cultured on zirconia disks and divided into 4 groups: smooth group(S),UV treated smooth group(S-UV),rough group(R) and UV treated rough group(R-UV). Cell proliferation was assessed by MTT 3 and 5 days after culture. Alkaline phosphatase(ALP) activity was determined 3 and 7 days after culture. Cell mineralization was observed by Alizarin red dye staining 21 days after culture. The mRNA expression of OCN and OPG were examined by RT-PCR 7 and 14 days after culture. Results: Proliferation and mineralization of MC3T3-E1 cells in R-UV group were more than in other groups(P ＜ 0. 05). R groups showed higher ALP activity than S groups at day 7. R-UV treatment increased the mRNA expressions of OPG and OCN in a time-dependent manner(P ＜ 0. 05). Conclusion: Ultraviolet light-treated zirconia surface may promote the proliferation,mineralization and the expression of OCN and OPG of MC3T3-E1 cells.
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Objective:To investigate the effects of bone morphogenetic protein 7 (BMP-7) on the biological properties of osteoblasts exposed to high glucose.Methods:MC3T3 cells were cultured in the high glucose condition and were divided into 4 groups according to BMP-7 concentration (ng/ml):0 (control group),50,100 and 200 ng/mL BMP-7 (test groups).The cell proliferation and ALP activity were examind 1,3,5 and 7 d after exposure.The number of intracellular calcium nodules were observed with Alizarin red staining after osteogenesis induction for 21 days.The F-actin cytoskeleton of MC3T3 was stained with Rhodamine and examined 24 h after culture.The mRNA expression of OCN and Runx2 were quantified by RT-qPCR 48h after exposure to BMP-7.Results:BMP-7 significantly promoted proliferation of MC3T3 cells and enhanced ALP activity(P ＜ 0.05),increased the number and volume of intracellular calcium nodules.In the cells exposed to BMP-7,the osteoblast form was improved and F-actin cytoskeleton started to change with network structure.Compared with control group,the mRNA levels of OCN and Runx2 were up-regulated in BMP-7 groups (P ＜ 0.05).The mRNA levels of OCN and Runx2 were the highest in 200 ng/ml BMP-7 group(P ＜ 0.05).Conclusion:BMP 7 may inhibit the action of the high concentration of glucose on MC3T3 cells.BMP-7 may be benificial to osseointegration of dental implant in patietents with diabetics.
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Objective:To investigate the effects of titanium spcimens with different surface character on the proliferation and mRNA expression of IL-6 and Cbfα1 in osteoblasts.Methods:Titanium surface was treated by smooth pretreatment(PT),sandblast and acid etch(SLA)and anodic oxidation(AD)respectively.The morphology and the elements analysis of the spcimens were inspected and detected by SEMand EDS.The surface contact angle was measured by contact angle meter.MC3T3-E1 cells were cultured on the titanium surface and cells cultured on tissue culture plate were served as the control group.The proliferation was measured by MTT assay.The mRNA expression of IL-6 and Cbfα1 was quantified by RT-qPCR.Results:The sample surface in PT group showed scrat-ches,in SLA group showed multiple three dimensional structure,in AD group exhibited porous structure.The elements of the sample surface of group PT,SLA and AD were Ti,Ti/Al and Ti/O respectively;the contact angles were 54.47°±3.33°,75.42°±8.32° and 38.91 °±4.00°respectively(P<0.05).The cells in AD group showed higher proliferation than those in PT and SLA groups(P<0.05).In AD group IL-6 mRNA expression decreased and Cbfα1 mRNA increased more than in PT and SLA groups(P<0.05). Conclusion:Titanium spcimens treated with AD may promote cell proliferation,decrease IL-6 mRNA expression and increase Cbfα1 mRNA expression in MC3T3 cells.Implats treated with AD might have some advantages in early osseointegration.
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BACKGROUND:Studies have confirmed that nicotine affects the activity of osteoblasts, osteoclasts, fibroblasts and erythrocytes. OBJECTIVE:To study the nicotine effects on osseointegration and the expression of osteoprotegerin and bone morphogenetic protein 2 after implantation of dental implants with surface treatment by sandblasting or acid etching. METHODS:Twenty-four Sprague-Dawley rats were randomly assigned to two groups and received daily injections for 2 weeks as folows: Nicotine 2 mg/kg twice for experimental group, saline solution for control group. Then the titanium implants with surface sandblasting or acid etching were implanted into the tibiae folowed by continuous nicotine or normal saline injection. At weeks 2 and 4 after implantation, the implants and surrounding bone tissue were prepared for CT, X-ray and hematoxylin-eosin staining examinations to evaluate bone healing and expression levels of bone-related genes were measured by quantitative RT-PCR. RESULTS AND CONCLUSION: Compared with the control groups, the degree of osseointegration and the expression of osteoprotegerin and bone morphogenetic protein 2 in the experimental groups were decreased significantly (P < 0.05), except that the expression of bone morphogenetic protein 2 in the experimental group with acid etching was not significantly reduced. In addition, the expression of bone morphogenetic protein 2 in the experimental group with acid etching was higher than that in the experimental group with sandblasting at 2 weeks after implantation (P < 0.05). The X-ray and CT show that the quantities of new generation bone and the degree of bone mineralization of the sandblasting group were significant lower than those of the acid etching group under the intervention of nicotine. Hematoxylin-eosin staining showed that the activity and quantity of osteoblasts around the implants down-regulated significantly, but acid etching-treated implants showed better outcomes than sandblasting-treated implants.
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Objective to probe into whether head-simulator teaching can enhance tooth cavity preparation compared with traditional preclinical teaching program.Method Questionnaires were conducted among the Grade 2002 students who had been trained by head-simulator teaching and were practicing in oral cavity section of our school.Result Majority of students think it's a good method and they have got better results than those trained in traditional experiment teaching.Conclusion The head-simulator teaching has improved the teaching quality of tooth cavity preparation but there exist some disadvantages which need further improvement and extension.
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Objective:To evaluate the effects of smokeless tobacco extract(ST) on number,morphology,ultrastructure and proliferation of human gingival fibroblasts(HGFs) on titanium in vitro.Methods:HGFs on titanium were cultured in the presence of ST at various concentrations.The cell changes in the morphology and ultrastructure were examined by scanning electrical microscope(SEM).The growth and attachment of the cells were measured by MTT method.Results:The size of the cells became smaller gradually and their shapes changed from spindle type to oval or round when the concentrations of ST increased.Ultrastructure showed that pseudopod decreased in number,the growth and attachment were dose-dependently inhibited.Conclusion:ST can change number,morphology and ultrastructure of HGFs on titanium,they can inhibit the cells growth,suggesting ST may play a pathological role on implant-gingiva interface.
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Objective:To study the antimicrobial susceptibility of periodontopathic bacteria associated with failing implants to commonly used antibiotics in periodontal therapy and dental practice.Methods:Antimicrobial susceptibility of bateria isolates was determined by the method of microbroth dilution and the activities of 8 kinds of antibiotics against international laboratory strains and clinical isolates of Provotella intermedia (Pro.I), Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn) were examined.Results:Ofloxacin, clindamycin, tinidazole and metronidazole showed stronger antibacterial activity aginst Pro.I,Pg,Aa and Fn with MIC_ 90 ≤0.5 ?g/ml and MBC_ 90 ≤0.5 ?g/ml.Conclusion:Commonly-used antibiotics are potential against bacteria isolated around failing implants.