Exploration on the cultivation of holistic thinking in endodontic practice teaching / 中华医学教育探索杂志

Objective:To investigate the effect of holistic thinking training mode on establishing clinical holistic thinking in endodontic practice teaching for students.Methods:Holistic thinking training mode was applied among Batch 2013 (group A, n=174) and Batch 2014 (group B, n=92) students of Guanghua School of Stomatology, Sun Yat-sen University. The teaching results were evaluated by the scores before and after the training and questionnaire, and by comparing their scores with those of Batch 2012 (group C, n=88) students. SPSS 20.0 was used to conduct one-way ANOVA and t test. Results:Compared the scores of students in group A with group B, the total scores before and after the training and the scores of "case report" were not statistically different, but the scores of holistic thinking were significantly improved after the training. Compared with the scores of students in group C, the total scores after the training and the "case report" scores of group A and B were significantly higher. The results of the questionnaire showed that 87.9%(153/174) of the students thought the training mode was conducive to the establishment of holistic thinking, but 77.6%(135/174) thought further improvement was needed in terms of content and time allocation.Conclusion:Holistic thinking training mode has a positive effect on the endodontic practice teaching, and is worth promoting in other departments after further improvement.

Detection Rate of Central Nervous System Leukemia Can Be Improved by Cell Preservation Solution / 中国实验血液学杂志

OBJECTIVE@#To investigate whether cell preservation solution can prolong the survival time of leukemia cells and increase the survival rate, so as to improve the detection rate of central nervous system leukemia.@*METHODS@#Kasumi cells were added into cerebrospinal fluid (CSF) supernatant with or without cell preservation solution to compare cell viability and biological characteristics at different time point. Wright Giemsa staining was used to compare cell morphology; cell counting, CCK-8 method, and trypan blue staining were used to compare the cell number, and flow cytometry was used to compare the cell viability. The expression of AML-ETO tumor fusion gene was detected by fluorescence quantitative RT-PCR.@*RESULTS@#At different time points (8 h and 24 h), the survival, molecular biological characteristics and RT-PCR result of the cells in CSF with cell preservation solution were significantly better than those in normal cerebrospinal fluid.@*CONCLUSION@#Cell preservation solution can effectively improve the survival time and survival rate of leukemic cells, thereby increase the detection rate of CNS leukemia.

Application and thinking of cone beam computed tomography directing technology on teaching of dental microscope treatment to endodontic disease / 中华医学教育探索杂志

Endodontic treatment with the use of dental operating microscope is a difficult part in teaching. We have applied cone beam computed tomography (CBCT) guided technology for microendodontic training of dental students who are in their 5th year of the 7 year course to pursue their master's degree. The process of teaching is constituted of preoperative analysis, operation guided by CBCT, postoperative therapeutic evaluation. And the result of teaching quality is acquired by questionnaire. This method improved student's capacities of analysis and solution in intractable cases and greatly motivated students' participa-tion, as well as promoting their learning efficiency. The application of this technique in teaching process compensates the deficiency of traditional teaching method by shaking off the fetters of experience-dependent pattern in the endodontic microscope teaching, and is worth to be popularized in endodontic education.

Biomodifying effect of epigallocatechin-3-gallate on dentine substrate splicing surface / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of epigallocatechin-3-gallate (EGCG) on biomodification of demineralized dentine substrate, in its permeability, hydrophobicity, and inhibition ability to collagen enzymatic degradation.</p><p><b>METHODS</b>The dentine substrates were treated with simulated pulpal pressure created by mixtures of 0.02%, 0.1% EGCG/bovine serum albumin (BSA) in acidic environment (pH4.4) for 48 h. A fluid-transport model was used to measure the fluid permeability through demineralized dentine substrate. Positive replicas of dentine substrate were fabricated before and after being subjected to acidic environment for scanning electron microscope (SEM) examination. The blank group contained no EGCG and the positive group were treated with Gluma desensitizer. Static contact angle measurements on demineralized dentin and 0.1% EGCG primed dentin were performed by contact angle analyzer. The priming time were 60 s, 120 s, 0.5 h, 1 h. Dentine specimens bonded with Adper single bond 2 were subjected to 100 mg/L collagenase and observed under SEM. Resin-bonded specimens (with 0.02%, 0.1%, 0.5% EGCG priming, or without EGCG priming) were created for micro-tensile bond strength evaluation (MTBS). Resin-bonded specimens after thermol cycling were created for MTBS evaluation.</p><p><b>RESULTS</b>The fluid permeability in the blank control group increased ([151.3±22.3]%), the fluid permeability in 0.1% EGCG/BSA group decreased ([23.7±6.3]%). Compared to the blank control group, the contact angle of 120 s, 0.5 h, 1 h groups increased by 31.0%, 53.5%, 57.8% in deep dentin and 37.4%, 59.3%, 62.4% in shallow dentin. The SEM examination showed that 0.1% and 0.5% EGCG priming for 120 s significantly increased dentin collagen's resistance to collagenase. The immediate MTBS of 0.1% and 0.5% EGCG groups were (29.4±4.8) and (19.8± 4.9) MPa. After thermol cycling, the MTBS of 0.1% and 0.5% EGCG groups were (19.9±5.1) and (15.3± 6.3) MPa.</p><p><b>CONCLUSIONS</b>Under acidic environment (pH4.4), the 0.1% EGCG can reduce dentine permeability under acidic environment. The 0.1% EGCG can increase hydrophobicity of dentin substrate, and strengthen dentin substrate's resistance to collagenase hydrolysis, thus increased the resin-dentin bonding durability.</p>

Sealing properties of three resin-based sealers / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the sealing properties of three resin- based sealers, EndoREZ, RealSEAL and RealSEAL SE.</p><p><b>METHODS</b>Forthy-eight extracted human anterior teeth with single root and canal were prepared using ProTaper files with crown-down technique to F3. The teeth were filled with three sealer respectively with hot gutta- percha vertical condensation technique simulating the clinical situation. Leakage quantity was detected using computerized fluid filtration meter with 10 samples in each group. The cross section morphology of apical parts of roots of 5 mm was observed with scanning electron microscope and transmission electron microscope in 3 samples of each group, respectively.</p><p><b>RESULTS</b>The leakage quantity of EndoREZ, RealSEAL and RealSEAL SE were (2.61±0.60), (1.43±0.11) and (1.76±0.18) µl/min, respectively. The gaps between the the sealer and the canal wall were increased in in order of RealSEAL, RealSEAL SE and EndoREZ. No obvious demineralized dentin under EndoREZ and the smear layer was not completed removed. The partly demineralized dentin was observed under RealSEAL and the smear layer was totally removed. The partly demineralized dentin was seen under RealSEAL SE and the majority of smear layer was removed.</p><p><b>CONCLUSIONS</b>Among the three resin- based sealers, RealSEAL has the best sealing properties, followed by RealSEAL SE and EndoREZ.</p>

Biomimetic mineralization of a single-layer reconstituted type I collagen model induced by sodium tripolyphosphate and polyacrylic acid / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the functions of sodium tripolyphosphate (STTP) and polyacrylic acid (PAA) in the process of collagen biomimetic mineralization. This would allow future applications to other collagen matrices such as bone collagen or 3-D collagen scaffolds.</p><p><b>METHODS</b>Glass cover slips and transmission electron microscopy (TEM) grids were coated with reconstituted typeIcollagen fibrils. Mineralization of the reconstituted collagens was demonstrated with scanning electron microscopy (SEM) and TEM using a Portland cement-containing resin composite and a phosphate-containing fluid in the presence of PAA and STTP. The rest were immersed in a biomimetic remineralization medium without PAA and/or STTP (control).</p><p><b>RESULTS</b>In the presence of PAA and STTP in the mineralization medium, intrafibrillar mineralization based on the non-classical crystallisation pathway could be identified. Mineral phases were evident within the collagen fibrils as early as 12 h after the initially-formed amorphous calcium phosphate nanoprecursors were transformed into apatite nanocrystals. Collagens at 72 h were heavily mineralized with periodically arranged intrafibrillar apatite platelets. Conversely, only large mineral spheres with no preferred association with collagen fibrils were observed in the absence of biomimetic analogues in the medium (control).</p><p><b>CONCLUSIONS</b>Intrafibrillar apatite deposition can be achieved via biomimetic mineralization system containing PAA and STTP when amorphous calcium phosphate precursor is stabilized.</p>

Application and prospect on the resin-dentin adhesion in the root canal therapy / 华西口腔医学杂志

The application of adhesive root canal filling materials is the tendency in root canal obturation. The orientation is to develop the adhesive core material and sealer making a whole structure. In this review, we summarized the researches on the resin-dentin adhesion in the root canal obturation.

Expression of saliva-binding region of Streptococcus mutans pac in transgenic tomatoes / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To analyze the expression of foreign gene in the filial generation of the transgenic plants on the base of the original transgenic tomatoes seeds carrying the gene encoding saliva-binding region (SBR) in PAc of Streptococcus mutans (S. mutans) gained.</p><p><b>METHODS</b>The tomatoes total DNA was extracted by CTAB methods, and the filial generation transgenic tomatoes carrying the gene encoding SBR in PAc of S. mutans were selected by PCR. The tomatoes total RNA was extracted by trizol and the transcription of the foreign gene was analyzed by RT-PCR. Protein was extracted from fruit tissue and the content of the total protein was determined by Bradford's methods G250. The expression of foreign protein was analyzed by Western blot and the lever of the foreign protein was analyzed by ELISA.</p><p><b>RESULTS</b>The fragment encoding SBR in S. mutans PAc gene integrated in the tomato genomic DNA and was expressed. The foreign protein lever was up to 1.2% of the total soluble protein in tomato fruit tissue.</p><p><b>CONCLUSION</b>The foreign protein gene in the filial generation of the transgenic plants could express the foreign protein.</p>

Construction of plant expression plasmid of chimera SBR-CT delta A1 / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purpose of this study is to construct plant expression plasmid containing the gene encoding chimera SBR-CT delta A1.</p><p><b>METHODS</b>The target gene fragment P2, including the gene-encoded chimera SBR-CT delta A1 (3,498-5,378 bp), was obtained by standard PCR amplification. The PCR products were ligated with pGEM-easy vector through TA clone to form plasmid pTSC. The plasmid pTSC and plasmid pPOKII were digested by restricted endonuclease BamHI and KpnI, and the digested products were extracted and purified for recombination. Then the purified P2 and plasmid pPOKII were recombined by T4 DNA ligase to form recombinant plasmid pROSC; inserting bar gene into the plasmid and form pROSB plasmid. The recombined plasmids were isolated and identified by restricted endonuclease cutting and Sanger dideoxy DNA sequencing.</p><p><b>RESULTS</b>P2 gene was linked to pPOKII plasmid and formed recombinant plasmid pROSC. The DNA sequence and orientation were corrected. And bar gene was inserted into pPOSC and form recombinant plasmid pROSB.</p><p><b>CONCLUSION</b>Plant expression vector pROSC and pROSB containing the gene encoding chimera SBR-CT delta A1, which may provide useful experiment foundation for further study on edible vaccine against caries have been successfully constructed.</p>