mTORC1 signaling pathway regulates tooth repair / 国际口腔科学杂志·英文版

Tooth germ injury can lead to abnormal tooth development and even tooth loss, affecting various aspects of the stomatognathic system including form, function, and appearance. However, the research about tooth germ injury model on cellular and molecule mechanism of tooth germ repair is still very limited. Therefore, it is of great importance for the prevention and treatment of tooth germ injury to study the important mechanism of tooth germ repair by a tooth germ injury model. Here, we constructed a Tg(dlx2b:Dendra2-NTR) transgenic line that labeled tooth germ specifically. Taking advantage of the NTR/Mtz system, the dlx2b+ tooth germ cells were depleted by Mtz effectively. The process of tooth germ repair was evaluated by antibody staining, in situ hybridization, EdU staining and alizarin red staining. The severely injured tooth germ was repaired in several days after Mtz treatment was stopped. In the early stage of tooth germ repair, the expression of phosphorylated 4E-BP1 was increased, indicating that mTORC1 is activated. Inhibition of mTORC1 signaling in vitro or knockdown of mTORC1 signaling in vivo could inhibit the repair of injured tooth germ. Normally, mouse incisors were repaired after damage, but inhibition/promotion of mTORC1 signaling inhibited/promoted this repair progress. Overall, we are the first to construct a stable and repeatable repair model of severe tooth germ injury, and our results reveal that mTORC1 signaling plays a crucial role during tooth germ repair, providing a potential target for clinical treatment of tooth germ injury.

Expert consensus on dental caries management / 国际口腔科学杂志·英文版

Dental Caries is a kind of chronic oral disease that greatly threaten human being's health. Though dentists and researchers struggled for decades to combat this oral disease, the incidence and prevalence of dental caries remain quite high. Therefore, improving the disease management is a key issue for the whole population and life cycle management of dental caries. So clinical difficulty assessment system of caries prevention and management is established based on dental caries diagnosis and classification. Dentists should perform oral examination and establish dental records at each visit. When treatment plan is made on the base of caries risk assessment and carious lesion activity, we need to work out patient‑centered and personalized treatment planning to regain oral microecological balance, to control caries progression and to restore the structure and function of the carious teeth. And the follow-up visits are made based on personalized caries management. This expert consensus mainly discusses caries risk assessment, caries treatment difficulty assessment and dental caries treatment plan, which are the most important parts of caries management in the whole life cycle.

Effects of concentrated growth factors on the angiogenic properties of dental pulp cells and endothelial cells: an in vitro study

Abstract The aim was to investigate the angiogenic effects of concentrated growth factors on human dental pulp cells and human umbilical vein endothelial cells. Cells were treated with concentrated growth factor extracts. The CCK-8 assay and cell cycle assay were conducted to evaluate cell growth. Cell migration was evaluated by the Transwell migration assay. Angiogenesis-associated mRNA and protein expression levels were determined using quantitative real-time PCR and Western blotting, respectively. A tube formation assay was conducted to evaluate the angiogenic capacity in vitro. The data showed that compared with the control, concentrated growth factor extracts significantly promoted dental pulp cell proliferation and differentiation and endothelial cell proliferation and migration in a dose-dependent manner (p < 0.05). Concentrated growth factor extracts also promoted the tube-like structure formation of endothelial cells in vitro. The RT-PCR and Western blot results showed that concentrated growth factor extracts upregulated the expression of angiogenesis-related genes - chemokine receptor-4, platelet-derived growth factor, and vascular endothelial growth factor - in dental pulp cells. In conclusion, concentrated growth factors showed proangiogenic effects on dental pulp cells and endothelial cells and have good application potential for dental pulp revascularization.

Expression of osterix gene in the early stage of cranio-maxillofacial development in zebrafish / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression patterns of osterix in the early stage of cranio-maxillofacial developmental in zebrafish and to prepare for a further research of osterix gene in bone and tooth development.</p><p><b>METHODS</b>The osterix templates were amplified by PCR to generate DIG labeled antisense and sense probes. Whole mount in situ hybridization was used to analyze the expression patterns of osterix in the early stage cranio-maxillofacial development of zebrafish. The expression patterns of osterix gene in mineralization progresses of cranial and maxillofacial bones were compared. The osterix gene expression in tooth development and mineralization was highlighted by alizarin red staining.</p><p><b>RESULTS</b>Specific DIG labeled probes of osterixwere synthesized successfully. The whole mount in situ hybridization showed that the osterix expression was in the intramembranous ossification at 3 days post fertilization(dpf) and 4 dpf. The specific osterix expression in tooth at 5 dpf and 6 dpf were also observed. The sense probe served as a negative control. Osterix expressed in the unmineralized early bone matrix, the tooth matrix of the primary tooth(3V(1), 5V(1)) and the first replacement tooth(4V(2)).</p><p><b>CONCLUSIONS</b>Our findings showed that osterix might play roles in the process of the early mineralized bone matrix changing into the late mature mineralized bone matrix and the process of development and mineralization of tooth crown matrix.</p>

Retinoic acid signal pathway regulation of zebra fish tooth development through manipulation of the differentiation of neural crest / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of retinoic acid (RA) signal in dental evolution, RA is used to explore the influence of the mechanism on neural crest's migration during the early stage of zebra fish embryos.</p><p><b>METHODS</b>We divided embryos of wild type and transgenic line zebra fish into three groups. 1 x 10(-7) to 6 x 10(-7) mol x L(-1) RA and 1 x 10(-7) mo x L(-1) 4-diethylaminobenzaldehyde (DEAB) were added into egg water at 24 hpf for 9 h. Dimethyl sulfoxid (DMSO) with the concentration was used as control group. Then, antisense probes of dlx2a, dlx2b, and barxl were formulated to perform whole-mount in situ hybridization to check the expressions of the genes in 48 hpf to 72 hpf embryos. We observed fluorescence of transgenic line in 4 dpf embryos.</p><p><b>RESULTS</b>We obtained three mRNA probes successfully. Compared with DMSO control group, a low concentration (1 x 10(-7) mol x L(-1)) of RA could up-regulate the expression of mRNA (barx1, dlx2a) in neural crest. Obvious migration trend was observed toward the pharyngeal arch in which teeth adhered. Transgenic fish had spreading fluorescence tendency in pharyngeal arch. However, a high concentration (4 x 10(-7) mol x L(-1)) of RA malformed the embryos and killed them after treatment. One third of the embryos of middle concentration (3 x 10(-7) mo x L(-1)) exhibited delayed development. DEAB resulted in neural crest dysplasia. The expression of barxl and dlx2a were suppressed, and the appearance of dlx2b in tooth was delayed.</p><p><b>CONCLUSION</b>RA signal pathway can regulate the progenitors of tooth by controlling the growth of the neural crest and manipulating tooth development</p>

Investigation into a new professional English teaching system for postgraduate dental students / 中华医学教育探索杂志

In view of the weakness of the teachers' strength, students' lack of interest and the lack of unity of teaching materials in the foreign language teaching, Oral Medicine College of Chongqing Medical University carried out the reform to the professional foreign language courses in the postgraduate education period by strengthening the preparation of special teaching materials, reinforcing teaching staff construction, reforming teaching methods and creating a learning environment. The results of teaching assessment by students and peer-reviewers show that reform has achieved good results, and aiming at the problems in the teaching practice we also put forward such improvement measures as strengthening the student-centered teaching method, promoting new teaching methods and optimizing curriculum assessment programs.

Expression of connexin 43 gene during early dental development in zebra fish / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aims to investigate the expression of connexin 43 (cx43) gene during early development in zebra fish and provide a foundation for further research of cx43 gene in tooth development.</p><p><b>METHODS</b>Total RNA was extracted within 72 h after fertilization of zebra fish embryos and then reversed transcribed to generate the cDNA library. The specific fragments of the cx43 gene were then cloned and connected to the PGEMT vector. After confirming the constructed plasmid, the corresponding RNA polymerase was chosen, and the digoxin-labeled anti-sense mRNA probe of cx43 was synthesized in vitro. The cx43 gene expression of zebra fish indifferent stages was carried out by in situ hybridization. The relationship of the cx43 gene expression and anatomy of the pharyngeal teeth were compared by alizarin red staining.</p><p><b>RESULTS</b>The mRNA antisense probe of cx43 was acquired. The positive signal of sepia was observed in the different stages of zebra fish pharyngeal teeth after fertilization. After fertilization for 9 days, the expression site of cx43 in situ hybridization was overlapped in accordance with the anatomical site of the pharyngeal teeth.</p><p><b>CONCLUSION</b>cx43 gene participates in tooth development and mineralization process and plays a crucial role in later mineralization.</p>

Relationship between dental caries and salivary proteome by electrospray ionization ion-trap tandem mass spectrometry in children aged 6 to 8 years / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To explore the relationship between salivary proteome and dental caries and to promote the biomarker studies of dental caries susceptibility by comparing the salivary proteome of caries-active children and caries-free children with electrospray ionization ion-trap tandem mass spectrometry (ESI-MS/MS).</p><p><b>METHODS</b>Ten caries-active children and ten caries-free children were sampled. The salivary proteome of the two groups was studied, and the differential protein between the two groups was analyzed by ESI-MS/MS after sodium dodecyl sulfate polyacrylamide gel electrophoresis, filter-aided sample preparation, and liquid chromatography.</p><p><b>RESULTS</b>The concentration of salivary protein was higher in the caries-active group than in the caries-free group. The polypeptide counts of thecaries-active and caries-free groups were 602 and 481, which belonged to 286 and 227 proteins, respectively. The differential polypeptide count of the two groups was 361, and the differential protein count was 118. The detected proteins included matrix metalloproteinase-9 (MMP9), mucin-7 (MUC7), lactotransferrin (LTF), carbonic anhydrase 6 (CA6), azurocidin (AZU), and cold agglutinin.</p><p><b>CONCLUSION</b>The total salivary protein was higher in the caries-active group than in the caries-free group. The preliminary detection of differential proteins (MMP9, MUC7, LTF, CA6, AZU, and cold agglutinin) may lay some foundation for biomarker research of dental caries susceptibility.</p>

Research on the active impact of the domestic breast X-ray machine upgrade at the diagnosis breast disease / 中国医学装备

Objective:To discuss the active impact of the domestic breast X-ray machine upgrade at the diagnosis breast disease. Methods:After the transformation of domestic breast X-ray machine, adoption the IP board instead of the film cartridge, complete digital mammography system. Results:Computed X-ray imaging processing image quality is better than traditional X-ray photography piece, within two years, completed a total check of more than 400 patients, overall diagnosis rate more than 95%. Conclusion:Buy the CR system All levels of the hospital, Can take advantage of the existing the ordinary breast X-ray machine equipment, Carry out breast Digital Imaging System.

Application of team-based learning model in periodontics theoretical teaching / 中华医学教育探索杂志

Objective To explore the role of team-based learning(TBL)in the teaching of pe-riodontics for undergraduates. Methods Totally 38 2008 grade undergraduates majored in stomatology were divided into six groups according to previous test scores. Individual test,group test and group re-sponder were conducted successively . Average test scores before and intra class were calculated and questionnaires survey was conducted after the course. Results There was no significant correlation be-tween average test scores intra class and basic knowledge and preview effect(r=0.028,P>0.05). Ques-tionnaire survey demonstrated that learning motivation,learning interests,knowledge mastering and com-munication ability of students were significantly improved. Conclusion TBL teaching promotes the class-room atmosphere and improves team collaboration and learning enthusiasm. Students show high accep-tance for this new teaching modes,so it can be tried in the teaching of stomatology.

Application of team based learning in teaching of dental endodontics / 中华医学教育探索杂志

Objective To apply team based learning (TBL) in the teaching of dental endodontics for undergraduates in order to expand and deepen the TBL teaching in stomatology education.Methods TBL was used among 2008 grade oral undergraduates in Chongqing Medical University.Average test scores of 2008 grade undergraduates before and intra class were calculated and questionnaire was designed.At the same time,final examination scores between 2007 grade and 2008 grade under-graduates were compared.Results There was no significant correlation in average test scores before and intra class (r =0.027,P ＞ 0.05).Final examination scores were higher in 2008 grade than in 2007 grade.Based on the questionnaire survey,learning interests,sense of teamwork and classroom knowledge grasp of 2008 grade undergraduates were obviously elevated.Conclusions TBL teaching significantly improve students' learning effect and it can be promoted in stomotology education.

An experimental study on PAc and GTF gene vaccines of Streptococcus mutans against rats caries: antibody levels in saliva and serum / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The purpose of this study is to examine the levels of salivary SIgA and serum IgG induced by pcDNA3-pac and pcDNA3-gtfB immunization, so as to testify the antigenity of the two gene vaccines.</p><p><b>METHODS</b>36 28-day-old Wistar rats were divided into 6 groups, among which 3 experimental groups were vaccinated with pcDNA3-pac, pcDNA3-gtfB or pcDNA3-pac combined with pcDNA3-gtfB, respectively, one positive control was vaccinated with inactive whole cell of S. mutans JBP and other two negative controls were injected with the vector pcDNA3 or PBS buffer, respectively. All vaccines and materials were delivered with 100 micrograms by submandibular gland injection for 3 times. Then the restricted bacterial model of rat was constructed. Following that all rats were fed with cariogenic diet Keyes 2000 for 3 months, saliva and serum samples were collected to assay SIgA or IgG levels by ELASA.</p><p><b>RESULTS</b>The salivary S-IgA levels both in pcDNA3-pac combined with pcDNA3-gtfB group and inactive S. mutans cell group were higher than others (P < 0.01). In groups of pcDNA3 and PBS buffer, they were lowest (P < 0.01). The serum IgG levels in the three experimental groups and positive control were higher than that in negative control (P < 0.05). It was important that salivary SIgA in groups of gene vaccine and inactive S. mutans vaccination reached its peak at the 11th week after the first inoculation and kept until the end of the study.</p><p><b>CONCLUSION</b>Both pcDNA3-pac and pcDNA3-gtfB can express immunogenic protein and induce immune responses of mucosal and humoral immune system in gnobobiotic rats. It is also indicated that the joint gene vaccines immunization is an optimal choice for anticaries strategy.</p>

F-ATPase subunit uncEBF mRNA expression in Streptococcus mutans clinical isolates / 实用口腔医学杂志

Objective:To investigate the gene expression variety of different genotype of F-ATPase subunit uncEBF in Streptococcus mutans (S.mutans) and to evaluate the relationship among uncEBF gene expression levels, genotypes and the acidurance ability of S.mutans. Methods:The relative expression quantity of uncEBF gene against the housekeeping gene recA was determined by the two-step method of semi-quantitative RT-PCR in 18 clinical isolates of S.mutans(7 with genotype A uncEBF and 11 with genotyp B,10 with high acidurance and 8 with low). A gel documentation system and QUANTITY ONES software were used to assay the data. Results:uncEBF mRNA expression level in the isolates with genotype A uncEBF was higher than that in those with genotype B(P

Relationship between Mutans streptococci transmission from mothers to children and initial adherence properties / 实用口腔医学杂志

Objective:To investigate the relationship between Mutans streptococci (MS) transmission from mothers to children and its initial adherence properties.Methods:200 MS isolates were genotypied by AP-PCR to demonstrate transmission between 20 pairs of mother and child aged 3~4 years, and to detect the transmitted strains and non-transmitted strains of mothers. Then the adherence of the strains to salivary coated hydroxyapatite beads (SHA) were determined by 3H- thymidine incorperation assay.A restriction fragment length polymorphism (RFLP) study of the different regions(spap-a,spap-pv)of the spap were undertaken by endonuclease haeⅢ and AluⅠrespectively. Results:The transmitted strains showed weaker adherence properties than the non-transmitted strains (P

Relationship between genetic diversity of surface protein of Streptococcus mutans and dental caries.Ⅱ Sequence of V-region and P-region gene of surface protein of Streptococcus mutans / 实用口腔医学杂志

Objective: To sequence V-region and P-region gene of surface protein of serotype c Streptococcus mutans clinical isolates with different adherent abilities. Methods: The clinical isolates of serotype c S.mutans included two groups with different spaP-pv AluI genotypes, which were derived from previous studies in our lab. The genome DNA was extracted. The spaP-pv (2 060-3 157 bp) was amplified by PCR, then sequenced and analyzed. Results: Seven sites of AluI 5′-AG↓CT- 3′were included in the sequences of spaP-pv of both genotypes strains. The sequences of spaP-pv of ten a-genotype strains were the same except several site mutations, and so were those of b-genotype strains. Two different DNA fragments were revealed between a and b geotype strains. And they were located in the V-region of spaP. Conclusion: The mutation of gene encoding V-region of S.mutans clinical isolates might be related to the differences of adherent abilities .

An experimental study of gene vaccines pcDNA3-pac and pcDNA3-gtfB of Strept ococcus mutans against dental caries in rats:the influence on weight / 实用口腔医学杂志

0.05);by the end of the experiment that was 24.5?1.05,28. 3?1.29,26.6?1.19,10.2?1.81, 26.3?1.54 and 27.3?1.38 respectively (D vs each of the other groups P0.05). Conclusion: Gene vaccines pcDNA3-pac and pcDNA3-gtfB have no unfavo rable influence on weight of gnotobiotic rats,while the inactive whole cell vac cine has.