Objective To improve the biocompatibility of nanofibrous scaffolds by grafting magnetic nano-particles onto them.Methods Poly (lactic-co-glycolic acid) (PLGA)/ε-caprolactone (PCL)/gelatin (Gel) nanofibrous composite membranes (PPG) were fabricated by electrospinning.And then paramagnetic Fe3O4 nano-particles were assembled to the scaffolds by layer-by-layer (LbL) process.Contact angle meter,electronic universal testing machine,vibrating sample magnetometer were used to characterize the surface topography,hydrophilicity,tensile strength and magnetic properties.Osteoblastic cell line MC3T3-E1 was seeded onto the scaffolds.CCK-8 was used to detect the cell proliferation.Results FESEM showed the structure of the PPG-F scaffold was similar to that of extracellular matrix,and Fe3O4 particles were successfully grafted onto the scaffolds.Vibrating sample magnetometer results indicated that after being coated with Fe3O4 particles,PPG-F membrane was of super paramagnetic property.Both improved hydrophilicity and better cell proliferation were observed in PPG-F group (P<0.05).Conclusions Grafting magnetic Fe3O4 nano-particles onto nanofibrous scaffolds can obviously improve the biocompatibility.

Objective To construct a lentiviral vector for over-expression of human estrogen receptor alpha (ERα) genefor further estimating the effects of ERα gene on tooth-derived stem cell research.Methods pEGFP-ERα was used as a template and ERα gene was amplified by RT-PCR.The right sequenced ERα gene was reorganized into the lentiviral vector PMSCV-GFP for construction of PMSCV-ERα.293T cells were transfected with PMSCV-ERα and the expression level of ERα protein was detected by Western Blot.Results ERα gene was amplified and PMSCV-ERα was constructed.Western Blot results showed that the expression level of ERα protein was much higher in PMSCV-ERα group than the control group (PMSCV-GFP).Conclusions A lentiviral vector for over-expression of human ERα was successfully constructed in our research.

Objective To evaluate the quantity of new bone formation through maxillary sinus bone augmentation using space maintaining device and to assess the influence of perforation on it.Methods Space maintaining devices were made by pure titanium to keep the elevated space.Three adult male beagle dogs were subjected to extraction of the third premolar and all molars of both sides to create a model with bone volume deficiency in the maxillary posterior region.After the natural healing 3 months later,space maintaining devices were installed simultaneously with the elevation of maxillary sinus membrane using the lateral approach without the use of bone substitutes.A perforation of 2 mm in diameter was randomly created in one side.Three animals were sacrificed 3 months after the surgery.Results The histological examination of the specimens showed bone formation was found underneath the space maintaining device but didn′t fill the space.The shape of new bone was in accord with the outline of the elevated membrane.The newly formed bone was immature woven bone and composed of trabecular bone structure.New bone area was (8.17±5.63) mm2 and (9.92±4.65) mm2 respectively in the condition of membrane intactness and perforation.The difference was not significant.Conclusions New bone formation can be found in nongrafted maxillary sinus bone augmentation using space maintaining device and the small perforation has no effect on it.The mechanism of new bone formation remains to be explored.

Abstract: Objectives To study the friction forces of stainless steel(SS) archwires with different sizes and rocking chair curvature (RCC) in Empower self-ligating brackets (Empower SLB) so as to guide the orthodontists′ choice of the brackets and archwires.Methods The standard occlusal plaster model was selected as the study model,and it was bonded with the Empower SLB and buccal tubes in a dry condition.Then the frictional forces of two rectangular SS archwire sizes(0.46 mm×0.64 mm and 0.48 mm× 0.64 mm) with four RCC(0°,5°,10°,and 15°) which made 8 combinations were tested.Results According to the RCC of 0°,5°,10°,and 15° loaded by 2 rectangular stainless steel(SS) archwire sizes from the canines to the secondary premolar segment,(1) In all combinations,dynamic friction was slightly less than the maximum static friction; (2) With the same RCC,0.46 mm×0.64 mm SS had less frictional force than 0.48 mm×0.64 mm SS (P<0.05).(3) Archwires of the same size increased as RCC (0°,5°,10°,15°)increased,and the frictional force also gradually increased (0.46 mm×0.64 mm SS:0＜0.19 N＜0.35 N＜0.90 N; 0.48 mm×0.64 mm SS:0＜0.26 N＜0.43 N＜1.00 N.P<0.05).Conclusions The dynamic friction is slightly less than the maximum static friction in Empower SLB.The frictional force gradually increased with the growing of SS sizes and RCC.

Objective The aim of this study was to use high-resolution CBCT to evaluate the effects of three Ni-Ti rotary endodontic instruments-K3, Hero, and MTwo, on canal transportation and centring ratio. Methods 30 mesial roots of extracted mandibular molars were randomly divided into three groups with 15 teeth in each. The final instruments used were all #30/0.04.Teeth were scanned before and after instrumentation using CBCT to measure volume and shaping changes. Canal transportation and centring ratio were evaluated at 3 mm from the end of each root. The method developed by Gambill was chosen. Results No statistically significant differences were found among the three groups in terms of canal transportation or centring ratio at any level (P>0.05).These systems were able to produce centred preparations of canals with minimal transportation.Conclusions These three Ni-Ti rotary endodontic instruments can maintain the primary form of the root canal, and cause little canal transportation.

目的 构建雌激素受体α（estrogen receptor α,ERα）短发夹RNA（short hairpin RNA,shRNA）慢病毒表达载体，探讨其对根尖牙乳头干细胞（stem cells from apical papilla,SCAPs）体外成牙/成骨向分化的影响。方法 根据shRNA设计原则，合成用于体内干扰ERα的两条shRNA序列，重组入慢病毒载体PLKO.1。将PLKO.1对照组与ERα-shRNA (shERα-1和shERα-2)实验组分别感染SCAPs，western blot检测ERα的表达及其对SCAPs成牙/成骨向分化的影响。结果 测序结果证实重组质粒构建成功；体外实验表明，SCAPs转染ERα-shRNA后ERα蛋白表达水平降低，其中shERα-2组对ERα的下调作用更明显，两组ERα-shRNA中核心结合蛋白因子2（runt-related transcription factor-2,RUNX2）、成骨细胞特异性转录因子（osterix,OSX）、牙本质涎蛋白（dentin sialoprotein,DSP）和骨钙素（osteocalcin,OCN）的表达均有不同程度下调，与对照组相比具有显著性差异（P<0.05）。结论 慢病毒介导的ERα-shRNA成功在体外抑制了目的基因的表达，并显著影响了根尖牙乳头干细胞的成牙/成骨向分化。

Objective To explore the expression of Emmprin in gingival crevicular fluid around implants and changes of clinical indexes as well as the relationship between them after implants′ overload.Methods 3 male adult Labradors were selected,with 3 implants on each side of their mandibles.After the healing 3 months later,the test groups were screwed with high level healing caps to simulate occlusal overload together with direct touch with teeth from upper jaws,while the control groups used low level healing caps as well as extraction of maxillary teeth.In altogether 12 weeks,gingival crevicular fluid around implants was extracted by periopaper every two weeks and preserved at-24 ℃.Then ELISA method was used to test Emmprin concentration in each specimen.Meanwhile,implant probing depth (iPD),implant gingival indexes (iGI) and implant blooding indexes (iBI) were tested.Data was statistically analyzed with paired t test and ANOVA.The significance level was 0.05.Results From 2nd week to 12th week,Emmprin of test groups increased obviously compared to control groups; the concentration increased before dropping,peaking at week 6.However,the concentration of control groups kept steady all along.The differences were significant.Besides,iPD,iGI and iBI of test groups altered significantly,with the values peaking between week 8 and 10.Conclusions Occlusal traumas can change the concentration of Emmprin in gingival crevicular fluid around the implants,which peaks at week 6.iPD,iGI and iBI of overloaded implants change significantly,peaking between week 8 and 10.Regarding the implants exposed to overload occlusal force,the increase of Emmprin concentration occurs ahead of other clinical indexes,which indicates that Emmprin can be a potential signal for peri-implantitis.

Objective To investigate the effect of Am80 on murine macrophage RAW264.7 after P.gingivalis antigen stimulation.Methods RAW264.7 cells were stimulated by P.gingivalis antigen and treated with different concentrations of Am80.Cell growth was observed in each group under a phase contrast microscope; the proliferation of antigen-stimulated RAW264.7 cells with different concentrations of Am80 were detected by MTS assay; enzyme-linked immunosorbent assay(ELISA) was used to detect anti-inflammatory factor levels of IL-10 in cell culture supernatant.Results 10 nmol/L Am80 significantly inhibited the proliferation and differentiation of P.gingivalis antigen-stimulated RAW264.7 cells（P<0.001）while Am80 (10 nmol/L) significantly increased the secretion of IL-10 by antigen-stimulated cells (P<0.05); inverted phase contrast microscope showed that Am80 inhibited antigen-stimulated proliferation and differentiation of RAW264.7 cells.Conclusions Am80 (10 nmol/L) can significantly promote P.gingivalis antigen-induced murine macrophages secretion of anti-inflammatory cytokine IL-10,and it may inhibit P.gingivalis antigen-induced inflammation.

Objective To evaluate the antibacterial effects of bioactive glass (BG) of different concentrations on three species of planktonic bacteria,single bacterial biofilms formed by the planktonic bacteria,and the subgingival early mixed bacterial plaque.Methods The minimal inhibitory concentration(MIC),minimal bactericidal concentration(MBC),minimal biofilm eradicationconcentration(MBEC) of Streptococcus sanguinis(Ss),Actinobacillus actinomycetemcomitans(Aa) and Fusobacterium nucleatum(Fn) were assessed.Inert silica glass (SiO2)and bioactive glass of 20,40,80 mg/mL were used to treat early mixed bacterial plaque for 24 h.Confocal laser scanning microscopy(CLSM) was used to observe and analyze the thickness and average fluorescence intensity of the plaque. Results The MBECs of BG to single bacterial plaque biofilm were significantly greater than the MICs and MBCs of planktonic bacteria.MBECs were 2~16 times greater than MICs.With the concentrations of bioglass increasing,there was a relative decrease in the thickness,mass and vitality of the mixed plaque.Statistically there was a significant difference between the blank control group and SiO2 groups (P<0.05).Conclusions BG can inhibit and kill planktonic forms of Streptococcus sanguinis,Actinobacillus actinomycetemcomitans and Fusobacterium nucleatum as well as the single form of bacterial plaque biofilm.However,the effect on single form of bacterial plaque biofilm was much better.BG of low concentration had certain antibacterial effects on the subgingival early mixed bacterial plaque.

Objective To evaluate the influence of grinding,polishing,glazing,and degradation on the flexural strength of zirconia ceramics.Methods 36 specimens of zirconia ceramics were divided into 3 groups (grinding,polishing,and glazing),and specimens in each group were further divided into two groups based on different aging time,denoted as group 0 h (as control) and group 10 h (n=6).The specimens in group 10 h were autoclaved at 134 ℃,0.2 MPa for 10 h.X-ray diffraction (XRD) was used to estimate the relative amount of monoclinic phase of one specimen in each group.Additionally,three-point flexure test was used to calculate the flexural strength.Results No specimens exhibited the monoclinic phase before degradation.All groups exhibited an increase in the amount of monoclinic phase after degradation.The grinding group exhibited the highest amount of monoclinic phase,and the lowest amount was observed in the glazing group.Flexural strength test revealed that there were no significant differences regarding the flexural strength of any group (P>0.05).Conclusions Although all groups exhibited an increase in the amount of monoclinic phase after degradation,there was no influence of grinding,polishing,glazing,and degradation on the flexural strength of zirconia ceramics.

Objective To investigate the biological effect of Nd:YAG laser irradiation on the squamous carcinoma CAL-27 cell proliferation.Methods Squamous carcinoma CAL-27 cells were developed in the vitro,and when they were in the logarithmic phase,the cells were irradiated with different doses of Nd:YAG laser and observed under inverted microscopes.Then,the OD value was measured after 1,3,and 5 days.Results A significant stimulative and inhibitive effect was found respectively of the low and high intensity 1 064 nm laser (P＜0.05) on squamous carcinoma CAL-27 cell proliferation.Conclusions By low intensity 1064 nm Nd:YAG laser,the squamous carcinoma CAL-27 cell proliferation can be stimulated,the cells are morphologically ruled and their density increases.In contrast,the proliferation can be inhibited by high intensity laser,the cells are irregularly shaped and their density decreases.This finding will have a good reference value for the clinical application.

Objective 1) To investigate the apoptotic gene expression profile in T lymphocytes after aggregatibacter actinomycetemcomitans (A.actinomycetemcomitans) cytolethal distending toxin (CDT) infection,and to find out the molecules involved in this process.2) To explore mechanisms of the development and progression of aggressive periodontitis (AgP),and to provide potential biomarkers for diagnosis and therapy.Methods After human Jurkat cells were treated by A.actinomycetemcomitans CDT for 24 hours,annexin V/PI detection andelectron microscopy technology was employed to detect the apoptosis.Apoptotic gene expression was examined by quantitative real-time PCR.Results By flow cytometry,the proportion of apoptotic cells was 29.1% in treatment groups,and that in the control group was 6.3%.The typical features of apoptosis were observed under transmission electron microscopy in treatment groups,such as cell shrinkage,chromatin condensation,and marginalization.Five pro-apoptotic genes were upregulated,including GADD45A、TNFSF8、TRADD、TNFRSF10B and TP53.Conclusions A.actinomycetemcomitans CDT could promote apoptosis of human T lymphocytes,and the expression of related pro-apoptotic genes increases during this process.

Objective To study the effects of LED and halogen curing lights on the cure depth of composite resin of different colors.Methods Standard cylinder samples of FiltekTM Z350 and Premisa light curing composite were prepared for cure depth test. FiltekTM Z350 resin had three colors:A1B,A2B and A3B.Premisa resin had three colors:A1E,A2E and A3E.Composite resin of each color was made into 60 samples.The samples were divided into three groups equally.The three groups were cured by Demi LED curing light,Bluephase○R 20i curing light and ALC-50 halogen curing light respectively.Results The mean depth of the samples cured by Demi LED curing light for 10 s and Bluephase○R20i LED curing light for 10 s exceeded 3 mm.The difference between Demi LED and ALC-50,Bluephase○R20i and ALC-50 was significant,but there was no significant difference between Demi LED and Bluephase○R20i.The difference between A1E,A2E and A3E of Premisa cured by two LED curing lights was significant.Conclusions Under the same conditions,the cure depth of the two LED curing lights curing for 10 s is superior to the performance level of halogen curing light curing for 40 s.The two LED curing lights are suitable for routine oral clinical application.The darkening of composite resin color can makes a difference to the cure depth.

目的 应用CBCT判断分析根管治疗失败原因，比较CBCT与根尖X线片在诊断根管治疗失败方面的差异。方法 收集拍摄CBCT的根管治疗失败病例74例，对其病因以及影像学检查结果进行统计分析。结果 在所收集病例中，失败原因包括根管欠充、遗漏根管、牙周牙髓联合病变、牙折、冠渗漏、根管超充及根管侧穿。结论 根管欠充、遗漏根管是导致根管治疗失败的主要原因,牙周损害则是后期处理的疑难因素。CBCT可为病因的确定提供有力参考依据，且对后期治疗方案的制定起关键作用。

目的 应用口腔专用的CM-700d分光光度计比较洁牙和喷砂前后前牙色度的变化，为牙齿美容的临床和基础研究提供方法学的参考。方法 分别在暗室使用CM-700d分光光度计测量治疗前，洁牙后，喷砂后上下前牙中1/3的L*a*b*值，将洁牙前作为T1组、洁牙后T2组、喷砂后T3组。采用配对t检验分析各组间牙齿色度的差异，再计算其色差值。结果 三组的L*、a*、b*值均有统计学差异（P<0.05）,且洁牙、喷砂后L*值升高，a*值、b*值降低。T1T2、T1T3的色差为肉眼可察觉，T2T3则相反。结论 洁牙、喷砂均能改善外源性着色牙的色度值，洁牙、喷砂后牙齿亮度升高，红绿、黄蓝色品值降低，洁牙后的喷砂能进一步改善牙齿色度，且通过分光光度计分析牙齿色度变化，更具有准确、量化的评判标准。

Objective To explore the occlusal plane and different sagittal relationships of maxillary and mandible in female skeletal Class Ⅱ hyperdivergent malocclusion.Methods 48 adult females with high-angle skeletal Class Ⅱ malocclusion were selected .Lateral cephalograms of 48 adult females were taken and twenty-seven measurements of each person were obtained.The correlation of different sagittal relationships of maxillary and mandible and occlusal plane parameters,as well as correlation between the occlusal planes and the dental patterns was evaluated by Pearson correlation.Results ANB and OPP-FH had a very significant correlation.The height and inclination of upper second molar significantly correlated with OPP-FH.Conclusions There is a definite correlation between cant of posterior occlusal plane and different sagittal relationships of maxillary and mandible in female patients of skeletal Class Ⅱ hyperdivergent malocclusion.

Objective To investigate the adolescents′ knowledge of malocclusion and their awareness of orthodontic treatment in Lanzhou area. Methods 4981 middle school students from 4 urban districts of Lanzhou city were given a malocclusion investigation, and questionnaires were distributed to the students so that their motivation and consciousness of orthodontic treatment were known. Results In 4981 students, 3168 of them (65.61%) were malocclusion patients, among which 448 were having orthodontic treatment (14.14%). As for the reasons why 2720 patients didn′t have orthodontic treatment, 21.54% didn′t think they had malocclusion, and 20% thought study pressure hindered them from having the treatment. Conclusions The malocclusion rate of adolescents in Lanzhou area is high, while the rate of treatment is low, and the adolescents lack the knowledge of orthodontic treatment.

Objective To explore the clinical efficacy of making union crown restoration with adjacent tooth after hemisection to repair and retain molar teeth. Methods 43 patients, a total of 52 molar teeth which have individual root fracture，or individual root with serious periodontal disease or periapical disease were involved in the study, and root canal therapy and periodontal treatment were conducted after hemisection. Three months later, whether to fill the medullary cavity with resin or to make fiber post-core were decided according to the defect case of retained tooth body, and then union crown restoration with adjacent tooth were made. After follow-up for 2-3 years, clinical and radiological examination was carried out. Results 52 teeth which were repaired with union crown restoration with adjacent tooth after hemisection all had good masticatory function, with restorations kept solid, crown edges closed, and periodontal tissue in good health. X-ray showed new bone formation or no progressive bone resorption. The success rate was 100% during the follow-up period. Conclusions Hemisection has important clinical implications on preserving molar tooth which has individual root fracture, or serious periodontal disease and periapical disease. The use of union crown restoration with adjacent tooth can be a good method to restore the teeth morphology and occlusal function as long as the indications were strictly selected.

Objective To summarize the causes of the maxillofacial head-on collision injury in traffic accidents as well as the age, gender, nationality, distribution, treatment methods, results and experience. Methods 217 cases of maxillofacial trauma caused by traffic accidents were selected out of 848 cases in our hospital and then clinical analysis was done to the 217 cases. Results The soft tissue incisions in patients healed with period I, and most patients were satisfied with the recovered facial contour. Occlusion of 129 rigid internal fixation cases was restored to preoperative state, so was the mastication function. The occlusion of 2 patients with mandibular teeth missing too much was not so well restored. After 2~3 months postoperative function training, opening degree of all cases reached more than 3.5 cm. Conclusions The maxillofacial head-on collision injury has its specificity in terms of its pathogenesis, clinical manifestations and the treatment. The road design in border provinces, traffic control, quality-oriented education will be maxillofacial impact injury prevention measures.

Objective To evaluate the clinical effects of treating proximal cavities which have a shallow gingival wall by filling them with glass-ionomer cement and silver amalgam (double filling method). Methods 78 proximal cavities from 74 patients that have a shallow gingival wall were filled randomly by double filling method or silver amalgam alone. The success rates of filling were compared one year later. Results Compared with the silver amalgam alone method, the double filling method significantly improved the success rate of filling (87.23% vs. 61.29%, P<0.01). The total success rate of filling molar cavities was slightly higher than that of filling bicuspid cavities (78.79% vs. 75.56%), with no statistical significance. Conclusions The double filling method can significantly improve the success rate of filling the proximal cavities which have a shallow gingival wall.

This paper reported and analyzed a case with schwannoma arising from lingual nerve in the sublingual gland.After complete resection along the envelope of the schwannoma（neurilemmoma）which is a benign,slowly growing,usually solitary and encapsulated tumor,good outcomes of wound healing were harvested in the follow-up 3 months later without obvious sensory and motor abnormalities of tongue,and no recurrence was detected.Therefore,as to clinical diagnosis and treatment of the tumor which locates in sublingual gland,the schwannoma should not be excluded from differential diagnosis.

Dens invaginatus,which is an abnormality formation of teeth probably caused by the infolding of enamel organs or their proliferation penetrating into dental papillae,mainly occurs in maxillary lateral incisors.This paper describes the complex root canal treatment of dens invaginatus in mandibular lateral incisor with apical periodontitis.The endodontic treatment was performed successfully.At a follow-up examination nine months later,the tooth was free of clinical symptoms and the periradicular lesion was significantly diminished.

Treatment designs of the extraction or non-extraction borderline cases were complex,and they varied as different technologies were applied.With the development of advanced medical technology,clear aligners were widely accepted and their efficacy in moving orthodontic teeth had been verified.Some experts suggested that clear aligners had certain advantages over the conventional labial fixed appliances in treating extraction or non-extraction borderline cases with non-extracted plans.In this article,the three-dimensional features of clear aligners in moving teeth were discussed and their advantages over the fixed appliances were analyzed,both of which could provide the clinical reference for treating the extraction or non-extraction borderline cases.

Peutze-Jeghers syndrome (PJS) is an autosomal dominant genetic disease caused by a germline mutation in the STK11/LKB1 gene and associated with pigmentation in oral mucosa,perioral skin ect. and gastrointestinal hamartomatous polyps.Most patients′ mucocutaneous pigmentations emerged before gastrointestinal polyps.In recent years, the number of patients with pigmentation in oral mucous and perioral skin have gradually increased in the department of stomatology.With no subjective symptoms,they are not diagnosed as having Peutze-Jeghers syndrome until gastrointestinal examination.To enable stomatology medical workers better understand and diagnose Peutz-Jeghers syndrome,this paper will expound and summarize PJS in terms of etiology,tumor susceptibility,clinical manifestation,diagnosis,examination and treatment,and its prevention.

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are two members of omega-3 polyunsaturated fatty acids (ω-3 PUFAs).They have a lot of beneficial biological effects，such as preventing and treating angiocardiopathy,improving the development of brain cells.They are also anticancer and anti-inflammatory.This article will review the research progress on the anti-inflammatory effects of DHA and EPA,as well as their role in periodontitis.

Pain is "an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage". Orthodontic pain may negatively affect patients′ cooperation and has been reportedto be one of the most important factors in discouraging patients from seeking orthodontic care.This article reviews the existing literature regarding orthodontic pain,and seeks reliable answers to the questions that might arise in a clinical setting from the viewpoint of clinicians and patients/parents.