Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Nemotic dental pulp fibroblast

La nemosis est un processus d’activation cellulaire déclenché in vitro par la mise en culture tridimensionnelle (sphéroïde) de cellules mésenchymateuses saines et qui se termine inéluctablement par une mort cellulaire de type nécrose programmée. Les fibroblastes sont les entités cellulaires les plus représentées dans la pulpe dentaire. Le premier objectif de ce travail était de confirmer l’existence de la réaction némotique dans ces cellules pulpaires et de la comparer à celle du fibroblaste pulmonaire pris comme référence. La caractérisation de ce phénomène a permis de mettre en évidence des similitudes mais aussi des différences marquées entre ces deux types cellulaires, en termes de libération de cytokines, de production d’enzymes protéolytiques et d’expressions géniques. Le second objectif de cette étude était de différencier la réaction némotique d’une autre nécrose programmée, la nécroptose. La finalité de ce travail était d’objectiver si cette activation fibroblastique peut se retrouver in vivo lors de pathologies pulpaires.Nemosis is a cell activation process – induced in vitro when sound mesenchymal cells are forced to cluster (spheroids) – which inevitably leads to a programmed necrotic cell death. Fibroblasts are the most commonly found cells in the dental pulp. The first aim of this study was to confirm that nemotic reaction could be observed in these cells and to compare their behaviour with that of sound lung fibroblasts, employed as a reference model for nemosis. This process displayed not only important similarities but also differences between the two cell types studied regarding cytokines release, proteolytic enzymes production and gene expressions. The second purpose of this work was to discriminate between nemosis and necroptosis, which is a programmed necrotic cell death. Finally, this study aimed to highlight whether this nemotic cell activation can occur in vivo during dental pulp diseases

Traitements esthétiques des dyschromies et des pertes de substance moderées du secteur antérieur

RENNES1-BU Santé (352382103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Dental students’ observations about teaching of endodontic access cavities in a French dental school

International audienceINTRODUCTION: Teaching in French universities has undergone deep changes for several years. Dental studies are no exception to the rule. Endodontics is one of the most difficult fields requiring good knowledge of anatomy before performing clinical procedures. The access cavity is the key step of endodontic therapy. The aim of this study was to collect and understand what students feel and expect from theoretical and practical training on endodontic access cavity. MATERIALS AND METHODS: A questionnaire survey on the teaching and learning of endodontic access cavities in a French dental school was sent by e-mail to the 4th-year students (n = 66). The questionnaire consisted of 13 questions of different formats. Qualitative variables were analysed using a word cloud according to the words of the participants. Students were also asked how to improve teaching with new educational tools. RESULTS: 60 students answered the questionnaire (response rate of 90.9%). When students were asked which stage of endodontic treatment they feared the most, performing access cavity came in 3rd place. Upper molar (71%) and lower molar (58%) appeared to have the most difficult endodontic access cavities. Within the word cloud gathered after students’ answers analysis, the words "fear," "perforation," "cavity" and "axis" were highlighted. Amongst the 3 new educational tools proposed to students, most were in favour of realistic models of teeth with their ideal endodontic access cavity (79%). DISCUSSION: This study highlighted the feelings of students during their hands-on training on endodontic access cavities. Although they seemed satisfied with practical classes on endodontic access cavities, this step seemed to be stressful for students especially because of the great internal anatomical variabilities of teeth. To help them better understand the root canal anatomy and improve their training, students asked for new educational resources, especially macro-models of teeth with their optimal access cavities. CONCLUSION: This study showed that students are seeking for innovative resources in addition to traditional resources that would make it easier for them to visualise the root canal system and help them feel more comfortable and facilitate learning when performing endodontic access cavities

Mise en place de TP hybrides dans l apprentissage de la gestuelle en endodontie

A l ère des technologies numériques, de nouvelles pratiques pédagogiques visant à enrichir l enseignement magistral traditionnel se développent au sein de l Université de Rennes 1 depuis plusieurs années. Notre travail s inscrit ainsi dans un projet pédagogique pluridisciplinaire initié en 2010 au sein de l UFR d Odontologie de Rennes. En collaboration avec le Centre d Ingénierie et de Ressources Multimédia de l Université de Rennes 1, quatre fiches pédagogiques destinées aux travaux pratiques d endodontie ont ainsi pu être développées. Ces fiches traitent successivement des techniques radiographiques, de l obturation canalaire avec le système Thermafil® et des techniques de compactage thermomécanique. L objectif de ce nouvel outil pédagogique accessible en ligne est de fournir simultanément aux étudiants une version synthétisée du cours et une visualisation concrète du matériel et des étapes de manipulation spécifiques à chaque technique.RENNES1-BU Santé (352382103) / SudocSudocFranceF

Expression of factors involved in dental pulp physiopathological processes by nemotic human pulpal fibroblasts

International audienc

Design of 3D-printed macro-models for undergraduates' preclinical practice of endodontic access cavities

International audienceIntroduction Endodontic access cavity is one of the steps most feared by dental students. The objective of the present work was to show the design phases of different realistic macro-models of a lower first molar, showing root canal anatomy and the ideal access cavity. Materials and Methods Virtual models were designed with MeshMixer, MeshLab and Blender from the data collected (X-rays, CBCT and optical impression) and then printed. Two types of printers-FDM (fused deposition modelling) and SLA (stereolithography) printers-were used to obtain different prototypes which led to final models. A satisfaction questionnaire was then sent to students, after manipulation, to assess the relevance of these models. Results Two final models of a lower first molar with an extended size (x9) were finally printed with an SLA laser printer with a transparent liquid resin. The first model represented the tooth with its optimal endodontic access cavity. The second one was designed to be divided into two parts according to a mesio-distal axis in order to visualise the root canal system. Most students found these macro-models to be effective tools for endodontic training. Discussion 3D printing is a proven technology which is no exception in dentistry. Some authors have already proposed 3D-printed replicas of teeth for endodontic education. Macro-models have been designed, printed and made available to students during preclinical courses before and during training. Conclusion These educational macro-models should strengthen the knowledge and skills of students to improve their clinical and future practice within the dental office

Characterization of a programmed necrosis process in 3-dimensional cultures of dental pulp fibroblasts

International audienceAIM: To analyse and compare the expression of necrosis markers in human lung and dental pulp fibroblasts and to determine whether this process differs by the type of mesenchymal cell. METHODS: Human dental pulp fibroblasts were obtained from unerupted third molars. Sound lung and pulpal fibroblasts were cultured in vitro as spheroids to determine the expression of the necrosis hallmark cyclooxygenase-2 (COX-2) mRNA using RT-PCR and the concentrations of vascular endothelial growth factor (VEGF) and hepatocyte growth factor/scatter factor (HGF/SF) proteins using an ELISA test. Cell viability within spheroids was also compared with spheroid diameters over time. RESULTS: Increased expression of COX-2 and VEGF was found in all spheroids compared with corresponding monolayers. Although HGF/SF was highly expressed in MRC5 cells, dental pulp fibroblasts aggregates maintained only a basal level compared with monolayer cultures. Further, the observed progressive loss of viable cells explained the decreased diameters of spheroids over time. The results demonstrate that necrosis occurs in sound lung and pulpal fibroblasts. This cell death also displays differences between these two different cell types, as they do not produce the same growth factors quantity release. CONCLUSIONS: The necrosis process occurred in human dental pulp fibroblasts and is different between the two cell types studied. This in vitro experimental necrosis model could become an interesting inflammatory tool. More investigations are needed to compare necrosis process in dental pulp fibroblast and inflammation during pulpitis

Selected and simplified FDI criteria for assessment of restorations

International audienc

The use of FDI criteria in clinical trials on direct dental restorations: A scoping review

International audienceOBJECTIVES:A scoping review was conducted to explore the use of FDI criteria 10 years after their introduction. The first aim was to compare the amount of studies using the FDI and/or the modified USPHS criteria. The second aim was to analyse the use of the FDI criteria in clinical trials evaluating direct dental restorations.DATA:Listing of studies using FDI and/or USPHS criteria per year since 2007. Clinical studies related to the assessment of direct restorations using FDI criteria.SOURCE:Two systematic searches - regarding the use of FDI and modified USPHS criteria - were carried out on Medline/Pubmed in order to identify the studies published between 2007 and 2017. Authors of the included articles were contacted to clarify their choice of FDI criteria in their studies. ClinicalTrials.gov database was also queried for the on-going studies that use FDI and modified USPHS criteria.STUDY SELECTION:In the first review, all the clinical trials (randomized/non-randomized, controlled, prospective/retrospective studies) that used FDI criteria to evaluate direct restorations on primary or permanent teeth were included.CONCLUSIONS:16.3% of the studies used FDI criteria. The percentage of studies using them increased from 4.5% in 2010 to 50.0% in 2016. In average, 8.5 FDI criteria were used. The most employed criteria were: marginal adaptation (96.7%), staining (90.0%), fracture of material and retention (90.0%), recurrence of caries/erosion/abfraction (90.0%), post-operative sensitivity/tooth vitality (86.7%) and surface luster (60.0%). In addition, among the 27 on-going studies from ClinicalTrials.gov database, 51.9% use FDI criteria (including 87.5% with an open recruitment status).CLINICAL SIGNIFICANCE:FDI criteria were reported as practical (various and freely selectable), relevant (sensitive as well as appropriate to current restorative materials and clinical studies design), standardized (making comparisons between investigations easier). Investigators should go on using them for a better standardization of their clinical judgment, allowing comparisons with other studies