Objective:To evaluate the ability of calcium hydroxide removal using different irrigation methods and the effect on canal sealing.Methods:200 human single root canal premolar teeth were prepared.Divided the teeth randomly into 2 groups(each group 96 teeth,8 as control),one group filled with chemical calcium hydroxide and another filled with finished product calcium hydroxide.7 days after,divided each groups randomly into 6 subsets and remove the calcium hydroxide in the root canal(table1).Then each subset group choose 8 teeth randomly,observed by scanning electron microscope.Other specimens were obturated by lateral condensation of cold gutta-percha with a AH-Plus sealer,stained by Indian ink and then made into transparent teeth model.Results:At the same condition,there was no significant difference between group A and group B;the results of groups associated with ultrasonic were better than groups with injection syringe.The rinse solution EDTA was the best,distilled water was the worse.Dye penetration showed that the length of dye staining was no significant difference among all groups.Conclusion:Ultrasonic and sodium hypochlorite associate EDTA is the best method to remove the calcium hydroxide.But none of the methods and rinse solution used in this experiment can remove all of the calcium hydroxide.The calcium hydroxide remained influence on the root canal sealer is not predominance.

Objective To introduce the general international method for estimation of lifetime risk of developed cancer,and to estimate the lifetime risk baseline values of several kinds of cancers related to radiation exposures in China.Methods The risk estimation was based on the data from Chinese Cancer Registry Annual Report (2010) and China Population & Employment Statistics Yearbook (2009),and made according to the method previously published by National Cancer Institute (NCI) in USA.Results The lifetime risk of all cancer in China in 2007 was estimated to be 27.77％,that of lung cancer 5.96％,that of breast cancer for female 3.34％,that of all leukemia 0.14％,that of thyroid cancer 0.37％.The lifetime risks of all cancer were estimated to be 32.74％ for males and 24.73％ for females,and that was 36.47％ for urban residents and 26.79％ for rural people.Conclusions The lifetime risk of all cancer for males in 2007 was about 1.25 times as much as that for females.The value of all cancer for urban residents was about 1.35 times as much as that for rural residents.The lifetime risk of developed cancers in 2007 in China is lower than that in the developed countries,such as Japan.

BACKGROUND:Severely curved root canal preparation is the difficulty during clinical root canal preparation, and improper preparation may induce complications such as stage, root canal offset and apical open, which affect the quality of root canal preparation and apical closure. Therefore, it is important to choose a root canal preparation instrument which has the best cutting and forming ability. OBJECTIVE: To compare the shaping ability of Mtwo nickel-titanium rotary instruments, K3 nickel-titanium rotary instruments and stainless steel K-files for the preparation of curved root canals. METHODS:A total of 30 severely curved root canals of freshly extracted human maxilary molars were randomly divided into three groups, with 10 canals in each group. The canals were prepared by Mtwo instruments, K3 instruments and K-files, respectively. The instrument’s tip location in pre- and post-instrumentation radiographs of the three groups was recorded; the changes of root curvature, working length and working time in the three groups were measured and compared. RESULTS AND CONCLUSION:The root curvature showed no significant difference in the three groups before preparation (P> 0.05). The changes of root curvature after root preparation in Mtwo instrument and K3 instrument groups were significantly less than that in K-files group (P < 0.01), and no significant difference was found between Mtwo instrument group and K3 instrument group (P > 0.05). The root canal preparation time in the three groups showed significant differences (P < 0.01), which was the shortest in Mtwo instrument group and the longest in K-files group. The changes of working length after root preparation in the three groups showed no significant difference (P > 0.05). Mtwo nickel-titanium rotary instruments and K3 nickel-titanium rotary instruments are have high efficacy and strong shaping ability in preparing curved root canals.

Objective:To investigate the influence of 3 methods of fiber posts on fracture resistance of maxillary anterior teeth with flared root canals.Methods:32 human maxillary central incisors were assigned randomly to 4 groups(n =8).The crowns of the teeth were removed at a level 2 mm incisal to the cementoenamel junction(CEJ).After root canal therapy,flared canals were simula-ted in 3 groups.The flared canals were reinforced with resin cement(group A),resin composite(group B)and accessory posts (group C)respectively.In group D flared canals were not created.The same size fiber posts were cemented with resin cement in all groups.After posts cementation and composite resin core formation,all teeth were restored with metal crowns.Then the roots of the teeth were embedded in acrylic resin blocks up to 2 mm below the CEJ.The samples were loaded in a testing machine until failure occurred.Results:The maximum load value(N)for fracture of group A,B,C and D was 295.94 ±69.11,450.51 ±54.68, 479.37 ±77.81 and 618.51 ±87.42 respectively(F =118.127,P =0.000);group B vs C,P >0.05,between each 2 of the other groups,P <0.05.No significant differences were found among the groups in the number of repairable fracture patterns(P >0.05). Conclusion:Reinforcement of flared canal with resin composite and accessory posts can increase the fracture restance of the tooth root and the most of fracture patterns are beneficial for the second repair.

Objective To assess the efficacy of NaClO irrigation of root canal at different temperatures.(Methods Thirty) human teeth with single root-canal mandible premolar were instrumented using standard technique,then were divided into 3 groups,carrying on root-canal irrigation.group A: 5.25% NaClO+System B,group B:5.25% NaClO+15% EDTA,group C:5.25% NaClO+System B+15% EDTA.After the teeth root were split,the scanning electron microscope was used to observe the coronal third,middle third and apical third parts.(Results The) amount of remaining debris on root canal wall in group C decreased significantly,compared with group A and B.The differences of coronal third and middle third between group A and B,group B and C,group A and C were significant(P0.05),but there were significant differences between group A,B and C(P

In order to adapt to the development of society,an innovative talent cultivation system has been explored to train stomatological specialists with active innovation spirit and strong ability to practise.

Objective To evaluate hepatectomy for liver metastasis in breast cancer patients. Methods From May 1997 to May 2000, 18 primary breast cancer patients with metachronous liver metastases underwent hepatectomy. The clinicopathologic features and surgical results were analyzed. Results The actuarial 1,3-year survival rates after hepatic resection were 100% and 83. 3% for patients with solitary metastasis, and 90.9% and 54.5% for those with multiple foci. Conclusions Posthepatectomy long term survival was correlated with the number of foci in postmastectomy breast cancer patients suffering from heterochronous liver metastasis. Tumor size and TNM stage of breast cancer were not correlated with the survival. Aggressive surgery helps to prolong the survival.

Objective To study the effect and mechanism of CKLF-like Marvel transmembrane domain containing 5 (CMTMS) on prostate cancer cell proliferation,migration and invasion.Methods The inhibitory effects of CMTM5 on the migration of DU145 cells were studied in vitro by wound healing assay.The expression of the cell signal pathway PI3K-AKT protein was detected by Western blot.The inhibition of tumor growth was also studied in transplanted prostate cancer nude mice model treated with CMTM5 adenovirus.The expression of CMTM5 and ki-67 in transplanted prostate cancer tissue of the nude mice model was analyzed immunohisochemistically.Prostate tumor volume in the nude mice model and the proliferation were measured two weeksafter.injection..Results Wound healing assay showed that over-expression of CMTM5 can inhibit the migration of DU145 cells.The expression of pAKT and NF-kB was significantly decreased after the overexpression of CMTM5.The tumor volume (573.39 ± 175.24) mm3,weight (0.55 ± 0.11) g and proliferation index of prostate in CMTM5 orthotopic injection nude mice model were significantly smaller and decreased than those in the control group (1482.50 ± 327.86) mm3 and (1.31 ± 0.29) g (P ＜ 0.05).Conclusions Both in vitro and in vivo experiments demonstrate that overexpression of CMTM5 could suppress prostate cancer cell proliferation,migration and invasion.The effect may be conducted by PI3K-AKT signaling pathway.

OBJECTIVETo detect the ability of Enterococcus faecalis (E. faecalis) biofilm formation and explore the relationship between E. faecalis biofilm formation ability and clinical manifestation.

METHODS96 well plate with the establishment of 53 E. faecalis in vitro biofilm model, combined with crystal violet staining, was used to test the biofilm formation ability of the clinical isolates E. faecalis and analyze the relationship between biofilm formation capacity and clinical manifestation.

RESULTSIn total 53 E. faecalis strains, 40 strains(75.47%) had biofilm forming ability. Statistical analysis revealed that the capacities of biofilm formation between E. faecalis isolated from with fistula and without fistula was significantly different (P<0.05).

CONCLUSIONIn the retreatment of root canal, the ability of biofilm formation of E. faecalis separated from the teeth without fistula is better than those separated from the teeth with fistula.

Objective To investigate the influence of early growth response gene-1 (EGR1) on the autophagy of host cells following infection with human T cell leukemia virus type 1 (HTLV-1).MethodsA HTLV-1-positive cell line MT2 was co-cultured with HeLa cells for 24 h to construct the virus early infection model.Immunoblotting assay was used to detect the expression of HTLV-1 core protein p19 and EGR1.Luciferase reporter gene analysis was used to detect the transcriptional activity of 5′-regulatory sequence of EGR1 at different time points after co-culturing.An effective small interfering RNA (siRNA) targeting EGR1 was screened out and transfected into HeLa cells by Lipofectamine 2000.Then the transfected HeLa cells were co-cultured with the HTLV-1-positive cell line MT2 for 24 h.Immunoblotting assay was used to detect HTLV-1 core protein p19, EGR1 and autophagy-related protein LC3.Real-time PCR was performed to detect viral load.Autophagosome was analyzed by immunofluorescence after co-culturing.Results The expression of EGR1 and the transcriptional activity of pEGR1-luc gradually increased after co-culturing HeLa cells with MT2 cells for 8 h (P<0.01).The expression of EGR1 was positively correlated with host cell autophagy following HTLV-1 infection.The effective siRNA for silencing the expression of EGR1 was obtained and named as siE2.The viral load, the expression of HTLV-1 core protein p19 and the proportion of LC3B/LC3A in the co-culture model were markedly down-regulated by RNA interference with siE2, which was concomitant with a persistent decrease of intracellular autophagosome (P<0.01).Conclusion EGR1 is associated with host cell autophagy and viral replication in HTLV-1 infection.