BACKGROUND:Obturation with warm gutta-percha can achieve perfect three-dimensional root canal obturation effect. Due to specific structure of oval canal, particularly in the bypass preparation process, excessive cutting of local tooth tissue may lead to tooth tissue thinning and irregular shape. The separation equipment is the metal with good heat conduction, so the heat caused by the bypassing warm gutta-percha obturation would burn periodontal tissue remains controversial. OBJECTIVE:To investigate the changes of root surface temperature produced by two bypassing warm gutta-percha obturation for the separation instrument in oval canalin vitro by using infrared thermography. METHODS:Forty mandibular first premolars were harvested from oval canals, and were separated using stainless steel 15# K file at apical 3 mm, with the length of 3 mm. The root canal bypassing was prepared using TF nickel-titanium file under operating microscope. The teeth were randomly divided into two groups, with 20 teeth in each group, and were obturated with the Thermafil warm gutter-percha and E&Q plus warm gutta-percha vertical compaction, respectively. An infrared thermoviewer was used to measure the external root surface temperature before and after the obturation. RESULTS AND CONCLUSION:Two warm gutta-percha obturation methods used for separating instruments bypassing in the oval root canal, had both caused the rise of root surface temperature, which was less than 10℃. In the Thermafil group, the temperature changes were 3.2-8.1℃ and the average change was 4.97℃. In the vertical condensation group, the temperature changes were 5.5-9.8℃ and the average change was 7.35℃. There were significant differences in the change of root surface temperature between the two groups (P < 0.05). Thermafil warm gutter-percha obturation would increase the root surface temperature, but cannot damage periodontal tissues. It is more secure than warm gutta-percha vertical condensation.

Objective To investigate the functional and structural changes of connectivity of default mode network (DMN) in relapsing-remitting multiple sclerosis (RRMS) by functional MRI (fMRI) and diffusion tensor imaging (DTI) and to study the relationship between them.Methods Twenty-seven RRMS patients(clinically diagnosed as RRMS)and 27 healthy volunteers (matched to the patients in age and gender) were selected to participate in this study.All the subjects underwent 3.0 T MR scanning.Softwares such as DPARSF,MICA,TrackVis were used for data post-processing.Medial prefrontal cortex (mPFC) and posterior cingulate cortex(PCC) of DMN were chosen as ROIs,and functional and structural changes of DMN and the relationship between them were analyzed.Values of r reflecting the functional connectivity and fractional anisotropy(FA) of two groups were obtained.Then statistical analysis was performed by using student t test and Pearson correlation analysis.Results The DMN space pattern of the RRMS patients was mostly identical to that of controls,but with specific difference in the connectivity strength with respect to that of controls.Particularly,the patient group showed increased DMN connectivity in the mPFC,but decreased connectivity in the inferior parietal lobule (IPL) and PCC.Compared with controls,the r value (0.695 ±0.151 vs.0.796±0.085),FA value(0.261 ±0.012 vs.0.285 ±0.017) between mPFC and PCC in RRMS patients were decreased (t =-3.020,-6.206,P ＜ 0.05).In addition,functional connectivity (r value) was found to correlate with structural connectivity(FA value) between the PCC and mPFC (r =0.704,0.735,P ＜ 0.01).The number of MS lesion,had no correlation with r value or FA value (P ＞ 0.05).Conclusions The functional connectivity and structural connectivity of DMN change in RRMS patients.The functional connectivity and structural connectivity between mPFC and PCC are both decreased in RRMS patients compared with the controls.The injury of structural connectivity may be the structural basis of the decrease of functional connectivity.

ObjectiveTo study tear film functions of diabetes mellitus with pterygium before and after surgery.MethodsNinety patients with single side pterygium were divided into 3 groups with 30 cases each:simple pterygium (treatment group A ),pterygium combination with type 1 diabetes mellitus (treatment group B) and pterygium combination with type 2 diabetes mellitus(treatment group C).Ninety patients without pterygium were divided into 3 groups with 30 cases each:normal (control group A),type 1 diabetes mellitus (control group B) and type 2 diabetes mellitus (control group C ).Tear film functions were compared in each group before surgery,while tear film functions in treatment group B and C were compared between before and after surgery.ResultsBefore surgery,there was no significant difference among each group in lacrimal secretion test.Every group's tear film break-up time(BUT) was abnormal except control group A.Cornea fluorescein staining (CFS) score in treatment group B compared with control group B,and treatment group C compared with control group C were significant differences [ (9.08 ± 0.48 ) scores vs.(3.43 ± 0.51 )scores and (10.31 ±0.94) scores vs. (7.91 ±0.51 ) scores,P＜0.05].There was significant difference in mucus fern test(MFT) between treatment group B and control group B (P＜0.05).Tear clearance rate (TCR) were all abnormal except control group A.Before surgery compared with after surgery between treatment group B and treatment group C,there was no significant difference in lacrimal secretion test (P＞0.05 ),but there were significant differences in BUT,CFS score and MFT,the TCR were normal.Conclusion Diabetes mellitus with pterygium will aggravate damage in tear film functions,and these damaged functions could be recovered through pterygium surgery with conjunctival limbal autograft.

BACKGROUND:Due to the complexity and irregularity of bypass obturation of oval root canal and the particular stress of the post and core to the tooth, we have not yet found a reasonable post crown for dental restoration after bypass obturation of the oval root canal.
OBJECTIVE:To compare the flexural capacity of the three kinds of post-and-core repair systems (cobalt-chromium cast post and core, zirconium oxide post and core, and CAD/CAM-fabricated glass fiber post and core) after bypass obturation of the oval root canal warm gutta.
METHODS: Ninety mandibular first premolars were selected for bypass obturation of the root canal with Obtura II & System B, and then randomized into three groups that were respectively restored with cobalt-chromium cast post and core, zirconium oxide post and core and CAD/CAM-fabricated glass fiber post and core. After that, cobalt-chromium metal crown was used for ful-crown restoration. Fracture strength and fracture type were recorded in different groups.
RESULTS AND CONCLUSION: The fracture resistance was higher in the cobalt-chromium cast post and core group and zirconium oxide post and core group than the glass fiber post and core group (P < 0.05), and the former two groups had no significant difference. Cobalt-chromium cast post and core was fractured at the root of tooth, and could not be repaired; the zirconium oxide post and core was fractured at the root neck and root of tooth, which was confirmed as reparative fracture; the glass fiber post and core was fractured at the tooth neck, which could be restored. These findings indicate that the cobalt-chromium cast post and core can bear greater occlusal force, but has a higher probability of root fracture; the CAD/CAM-fabricated glass fiber post and core exhibits a lower probability of root fracture

BACKGROUND:Currently, there are many studies on colapsed repair, but a systematic and horizontal comparison is not reported yet. OBJECTIVE: To compare the effect of conventional resin adhesive, resin adhesive+silane coupling agent and adjacent surface open part of the crown on colapsed repair through clinical trial and in vitro experiment. METHODS: (1) Clinical trial: 90 patients with porcelain colapse were randomized into three groups, and respectively treated with conventional resin adhesive, resin adhesive+silane coupling agent and adjacent surface open part of the crown. Success rate was measured and compared among three groups at 1 year after repair. (2) In vitro test: Twenty test specimens were equaly divided into two groups, and treated with conventional resin adhesive and resin adhesive+silane coupling agent, respectively. Then, shear strength was detected in the two groups. Twenty double-crown specimens were equaly divided into four groups. The first three groups were treated with sand blasting, silane coupling agent and their combination treatment, respectively; the rest group had no treatment (control group). After repair, the tensile strength of each specimen was detected.RESULTS AND CONCLUSION:The success rate of colapsed repair was 37% for conventional resin adhesive, 90% for resin adhesive+silane coupling agent and 100% for adjacent surface open part of the crown. The shear strength was (13.978±0.343) MPa for the conventional resin adhesive and (10.058±0.64) MPa for resin adhesive+silane coupling agent, and there was a significant difference between two methods (P < 0.01). The tensile strength was (0.68±0.04) kN in the control group, (1.00±0.02) kN in the sand blasting group, (1.31±0.08) kN in silane coupling agent group, and (1.09±0.04) kN in the combination group, and there was a significant differences between groups (P < 0.01). Experimental results show that the silane coupling agent+resin adhesive treatment and adjacent surface open part of the crown are superior to conventional resin adhesive.

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Molecular technologies are sensitive, fast, and cheap in the study on microbial ecology. However, these methods do not provide information about morphology, number, and spatial distribution of the microorganisms. In contrast, Fluorescence in situ hybridization (FISH) combines the precision of molecular biology with the visual information from microscope, and permits visualization and identification of individual miciobial cells within their natural habitat. FISH not only allows the detection of slow growing microorganisms, but also of yet-to-be cultured. It is useful for many applications in diagnosis and assessment of the population structure of complex microbial communities, and is a powerful tool for molecular ecology studies in microbiology, In this paper, major techniques and progresses of FTSH were described. Its application in microbial ecology, as well as problems , pitfalls, and perspectives of FISH are discussed.

Objective To investigate the role of plasmid pYC on proteome of Yersinia pestis. Methods Two dimensional electrophoresis was performed to strains of Yersinia pestis with and without the pYC plasmid, and differential proteins were identified by mass spectrometry. Results More than 500 protein spots of Yersinia pestis with and without plasmid pYC were recognized,and their protein profiles were generally similar. The chaperone GroEL was highly expressed in strains with plasmid pYC, whereas the protein GroEL was not encoded by plasmid pYC. ConclusionsPlasmid pYC has an impact on proteome of Yersiniapestis. The proteins of pYC-p10 and pYC-p11 encoded by plasmid pYC may regulate the expression of GroEL.

Objective:To study the lethal effect of vitamin C carbon dots on oral squamous cell carcinoma KB cells, and to clarity its related mechanism.Methods: The KB cells were treated with different concentrations (5, 10, 20, 40 and 80 mg·L-1) of vitamin C carbon dots in vitro as experimental groups, and 0 mg·L-1 vitamin C carbon dots group was used as blank control group.MTT assay was used to detect the proliferation rates of KB cells in various groups;colony formation assay was used to detect the colony formation ability of KB cells;Western blotting was performed to detect the protein expression levels of autophagy related protein LC3 in KB cells in various groups;flow cytometry was used to detect the apoptotic rates of KB cells in various groups.Results: Compared with blank control group, the proliferation rates and colony formation abilities of KB cells in 20, 40 and 80 mg·L-1 carbon dots groups were markedly decreased (P<0.01).Compared with blank control group, the protein expression level of LC3 Ⅱ in 40 mg·L-1 carbon dots group was increased(P<0.05);the apoptotic rate of KB cells was markedly increased(P<0.01).Conclusion: Vitamin C carbon dots can kill the oral squamous cell carcinoma KB cells effectively, suppress the proliferation and impair the colony formation ability of KB cells, which is related to autophagy and apoptosis of KB cells.