目的 探讨不同浓度17β-雌二醇对原代人牙周膜细胞(human periodontal ligament cells,hPDLCs)增殖、细胞周期以及碱性磷酸酶活性的影响.方法 无菌条件下刮取人牙周膜组织,采用组织块结合酶消化法进行原代培养并用免疫组化法鉴定.处于对数生长期的第4代hPDLCs分别加入不同浓度的17β-雌二醇(10-5、10-6、10-7、10-8、10-9mol/L),培养24h、48h、72h和7d后,MTS比色法检测17β-雌二醇对hPDLCs细胞增殖的影响;流式细胞术检测hPDLCs细胞周期的变化;BCIP/NBT法检测17β-雌二醇对hPDLCs碱性磷酸酶活性的影响.结果 分离培养的原代hPDLCs中Vimentin呈阳性表达,而Cytokerain呈阴性表达,证实hPDLCs分离培养成功.17β-雌二醇能促进hPDLCs增殖,调控细胞周期进程并提高碱性磷酸酶活性,其中以10-8 mol/L浓度的作用最为显著.结论 一定浓度范围内的17β-雌二醇对hPDLCs增殖、分化有一定的诱导作用.

Objective To explore a simple and practicable cultivating mode of periodontal ligament cells (PDLCs) to shorten the cultivating period of primary periodontal ligament cells. This study combined tissue cultivation of PDLCs with enzyme digestion and used this combination method to isolate and culture PDLCs. Methods Take 25 premolars which need to extract because of orthodontics, and then use combination method to extract and cultivate the primary periodontal ligament cells. The success rate was calculated. Results Combined method can isolate and cultivate primary periodontal ligament cells. The PDLCs is elongated, and conform to the form and biological characteristics of PDLCs. The PDLCs grow well and the success rate is 40%. Conclusion The way of using combination method to extract and cultivate PDLCs is practicable, and the form and growth of the PDLCs are well.

目的:探讨翻转课堂教学模式在口腔本科正畸课间实习中的应用效果.方法:选取口腔医学本科学生作为研究对象,将60名学生随机分为实验组(翻转课堂教学)和对照组(传统教学),通过笔试考核、操作测试、问卷调查的方式进行评价.结果:实验组和对照组的理论考试成绩并无明显差异(P＞0.05),但是实验组的病例分析成绩高于对照组(P＜0.05).实验组的临床操作能力明显优于对照组.结论:翻转课堂教学模式能够很好地达到教学效果,值得在正畸本科课间实习中应用.

Objective To investigate the effect of Micro-class in orthodontic practicum for five-year undergraduate students in stomotology. Methods Experimental comparative method was used on two groups of undergraduate students. A total of 70 students in Grade 2011 were taught with traditional teaching mode as the control group, while 50 students in Grade 2012 were taught with Micro-class lecture as the observation group. The satisfaction questionnaires were distributed to both groups after the course to facilitate the eval-uation of teaching methods, which specifically was done by SPSS 21.0 for t test and Chi-square test. Results The results of survey showed that the satisfaction of the observation group was significantly higher than that of the control group, which exemplified in the studying interest inspiration, studying efficiency improvement, further development, and overall satisfaction [(4.00±0.73) vs. (3.05±0.77); (4.06±0.65) vs. (3.06±1.01);(4.86±0.35) vs. (2.64±0.80); (4.32±0.47) vs. (2.62±1.08)], (P<0.01). Conclusion Micro-class can improve the teaching quality, and it is meaningful to apply the micro-class in orthodontic practicum.

目的:探索口腔正畸本科课间实习教学方法新模式.方法:将90名学生随机分为对照组(传统教学)和实验组(新教学方法),通过理论考核、技能考核、问卷调查的方式进行评估.结果:实验组学生在实际操作和临床实践能力方面都明显优于对照组.结论:以提高实践能力为基础的新教学方法能提高学生的学习积极性并提高学生实践能力,值得在正畸课间实习课中推广.

MicroRNAs (miRNAs) are endogenously expressed small noncoding RNAs that regulate gene expression.It plays a critical role in cell proliferation,cell differentiation,and organism development.Current researches on miRNAs mainly focus on its antitumor effect while its role in periodontics lacks attention.This review is focusing on the differential expression of miRNAs in periodontitis,osteoblast,and osteoclast differentiation,and discussing their possible regulation mechanism on the basis of the latest progress on researches of miRNAs in periodontitis.

Objective To analyze the effect of Bite turbo combined with early classⅢelastics on the treatment of anterior crossbite. Methods 16 patients with anterior crossbite and deep overbite participated in the experiment. Bite turbo combined with early classⅢelastics was used and the clinical effect was observed. Lateral cephalograms were taken before treatment and after bite opening. The re?lated hard tissues were estimated through the cephalograms. Results After a short period of treatment, the anterior crossbite and deep overbite were corrected in all cases. SNB, ANB, MP?SN, ANS?Me, ANS?Me /N?Me, U1-SN, U6-PP, L6-MP, L1-MP, overjet and overbite were significantly changed. Conclusion Bite turbo combined with early classⅢelastics can be used effectively for ante?rior crosssbite correction.

BACKGROUND:316L-Cu antibacterial stainless steel is made by adding a certain amount of copper into the stainless steel fol owed by a special heat treatment to uniformly disperse copper-rich precipitates in stainless steel substrate, thereby harvesting the antibacterial properties. OBJECTIVE:To evaluate the antibacterial activity of the Cu ions released from 316L type Cu-bearing antibacterial stainless steels against Porphyromonas gingivalis, thereby providing biomedical evidence for its clinical application. METHODS:The medical 316L stainless steel samples at a surface area to volume ratio of 0.1 cm2/L were soaked in simulated body fluids at 37 ℃ for 1-10 days. A graphite furnace atomic absorption spectrophotometer was&nbsp;employed to detect the amount of Cu release in the simulated body fluids each day and then the rate of Cu release per day could be determined. The antibacterial activities of the steel samples were evaluated by a standard film-covered method under a scanning electron microscope. RESULTS AND CONCLUSION:The daily Cu releasing amount from the 316L-Cu stainless steel within 10 days was significantly higher than that of 316L stainless steel, and al the values remained nearly constant. With time, the sterilizing rate of 316L-Cu stainless steel was gradual y increased, and reached 100%until the 10th hour. Porphyromonas gingivalis showed some morphological changes at 3 hours after treated with 316L-Cu stainless steel, appeared with cleavage at 6 hours, and mostly disintegrated into pieces at 9 hours. The results indicated that the 316L-Cu antibacterial stainless steel showed excel ent antibacterial property against Porphyromonas gingivalis, slowly release Cu irons, and alter the surrounding microenvironment, which is a highly promising biomaterial and has good clinical value.

To evaluate the possibility of an alternative to the traditional orthodontic stainless steel implants, the antibacterial activity against Porphyromonas gingivalis (P. gingivalis) and the related cytotoxicity of a type 304 Cu bearing antibacterial stainless steel were studied. The results indicated that the antibacterial stainless steel showed excellent antibacterial property against P. gingivalis, compared with the control steel (a purchased medical grade 304 stainless steel). Compared to the control steel, there were fewer bacteria on the surface of the antibacterial stainless steel, with significant difference in morphology. The cytotoxicities of the antibacterial stainless steel to both MG-63 and KB cells were all grade 1, the same as those of the control steel. There were no significant differences in the apoptosis rates on MG-63 and KB cells between the antibacterial stainless steel and the control steel. This study demonstrates that the antibacterial stainless steel is possible to reduce the incidence of implant-related infections and can be a more suitable material for the micro-implant than the conventional stainless steel in orthodontic treatment.

Objective: To investigate the application of PBL in practice teaching of orthodontic.Methods: 60 students were divided into two groups.The teaching effectiveness was evaluated by questionnaire,test papers and discussion after class.Results: The evaluation shows that PBL group is superior to conventional teaching group in analyzing and solving problem.Conclusions: PBL can increase students' learning interest.

Objective To evaluate the cytotoxicity of antibiotic stainless steels by the methods of MTT and CCK-8.Mehtods Metal test samples were made into rectangular solids in size of 15 mm x 10 mm x 3 mm.Alloy leaching liquor was prepared with DMEM culture media according to the ratio of surface area and volume of culture solution(3 cm /ml).Growth of MG63 cells was observed under inverted phase contrast microscope;absorbance of cells cultured for 24 to 72 hours was detected using MTT and CCK-8 test;cytotoxicity of antibiotic stainless steels was evaluated.Results①After 48 hours' culture,with the culture time increased,cytotoxicity was detected in the positive control group;cells in other groups were normal and grew well.A few of cells in stainless steels group showed karyopyknosis.②Although the A value of antibiotic stainless steel group was higher than that of stainless steel group from MTT results,there was no significant difference between the two groups.③There were significant differences among the four groups from CCK-8 results.The A value gradually decreased from the negative control group to the positive control group.④The level of cytotoxicity in each of the test groups was grade 0.Conclusions①The antibiotic stainless steel is in line with the requirement of its clinical application by the cytotoxicity test.②The CCK-8 method is more sensitive and accurate than MTT and worth using.

BACKGROUND: The wear of orthodontic appliances can destroy the teeth and their surrounding tissue environment, which can result in plaque accumulation and a series of adverse reactions. OBJECTIVE: To detect the cytotoxicity of antibiotic stainless steels orthodontic appliances by CCK-8 and flow cytometry methods. METHODS: 1 The proliferation of cells was detected by CCK-8 method: human oral epithelial carcinoma cells KB which were in vigorous growth were extracted and cultured in 96-well plates. Alloy leaching liquor of the antibacterial stainless steels was added into the experimental group, while the leaching liquor of common stainless steels was added into the control group. The negative control group was added into Dulbecco's modified Eagle's medium medium, and the positive control group was added into phenol. The cells of each group were cultured for 24, 48 and 72 hours. 2 The apoptotic cells were detected by flow cytometry Annexin V-FITC/PI double staining: the effect of common stainless steels and antibacterial stainless steels materials on the apoptotic of human oral epithelial carcinoma cells KB in the logarithmic phase was investigated. The blank control group was set up. RESULTS and CONCLUSION: 1 After 48 hours of culture, the absorbance value of the positive control group was gradually decreased with the culture time increased; while the absorbance values of other groups were gradually increased with time (P < 0.05), what's more, the experimental group was higher than the control group (P < 0.05). The degrees of cytotoxicity in the common stainless steels and antibacterial stainless steels materials were both in grade 1. 2 The apoptotic cells in common stainless steel group and antibiotic stainless steel group were less than blank control group, besides, the apoptotic cells in the antibiotic stainless steel group were less than those in the common stainless steel group (P < 0.05). These findings suggest that the antibacterial stainless steel has good biocompatibility, and its toxicity grade is the same as that of common stainless steels, which meets with the requirements for the clinical application of orthodontic materials.

Objective The purpose of this study is to evaluate the cytotoxicity of antibiotic stainless steel. Methods Observe the growth of the L-929 cells in the extracted fluid of the antibiotic stainless steel,stainless steel and pure titanium by inverted phase contrast microscope. CCK-8 assay method was used to evaluate the cytotoxicity of three materials on L-929 cells on the 1st d,2nd d,and 3rd d. Results L-929 cells grew in eugonic way and showed normal morphology in all the extracted fluid of the three materials. No significant difference of OD was observed between the antibiotic stainless steel and stainless steel groups. Cytotoxical grades of three metal materials were 0 to 1.Conclusions It was found that there was no apparent cytotoxicity of antibiotic stainless steel. The antibiotic stainless steel is in line with the requirement of clinical application.

BACKGROUND:Prevention of implant from inflammation was an effective method to reduce expulsion rate of stainless steel micro-screw implant,and develop new type of antibiotic material.OBJECTIVE:To evaluate the cytotoxicity of a new type of antibiotic stainless steels.METHODS:Metal test samples(antibiotic stainless steel,medical stainless steel,and medial pure titanium)were made into rectangular solids with length of 15mm×10mm×3mm.Samples were cleaned with high temperature and high pressure.Alloy leaching liquor was prepared with DMEM culture media according to the ratio between surface area and volume of culture solution(3 cm2/mL).The leaching liquor was maintained in incubator at 37℃ for 96 hours,and then degerming was performed using microporous membrane.6.4% phenol was added,which was considered as the positive control group,and DMEM culture media was considered as the blank control group.Growth of MG63 cells was observed under inverted phase contrast microscope;absorbance of cells cultured for 24,48,72,96,and 120 hours was detected using MTT test;cytotoxicity of antibiotic stainless steels was evaluated.RESULTS AND CONCLUSION:①At 24 hours after culture,cells in the positive control group was abnormal;while,cells in other groups were well adherent-grew.②After 48 hours of culture,with the culture time increased,cytotoxicity was detected out in the positive control group;cells in other groups and blank control groups were normal and grew well.A few of cells in stainless steels group showed karyopyknosis.③The absorbance was the highest of medical pure titanium,and then of antibiotic stainless steel and of medical stainless steel,while there was no significant difference between the three materials.④The level of cytotoxicity was grade 0.The results suggested that the antibiotic stainless steel which had the same cytotoxicity grade as medical stainless steel and pure titanium was in line with the requirement of its clinical application.