Cone-Beam Computed Tomography contrast validation of an artificial periodontal phantom for use in endodontics

International audienceValidation of image processing techniques such as endodontic segmentations in cone-beam computed tomography (CBCT) is a challenging issue because of the lack of ground truth in in vivo experiments. The purpose of our study was to design an artificial surrounding tissues phantom able to provide CBCT image quality of real extracted teeth, similar to in vivo conditions. Note that these extracted teeth could be previously scanned using micro computed tomography (μCT) to access true quantitative measurements of the root canal anatomy. Different design settings are assessed in our study by comparison to in vivo images, in terms of the contrast-to-noise ratio (CNR) obtained between different anatomical structures. Concerning the root canal and the dentine, the best design setup allowed our phantom to provide a CNR difference of only 3% compared to clinical cases

The XP-Endo Finisher for the removal of calcium hydroxide paste from root canals and from the apical third

The aim was to compare the efficacy of the passive ultrasonic irrigation PUI and the Xp-endo Finisher (FKG-Dentaire, La-Chaux-de-Fonds, Switzerland) in removing the calcium hydroxide paste from root canals and from the apical third. Sixty-eight root canals of single-rooted teeth were shaped using the BT-Race files (FKG-Dentaire, La-Chaux-de-Fonds, Switzerland). Ca(OH)2 was placed in all samples except for the negative control group (n=4). Remaining teeth were randomly divided into three groups: G1-Xp (n=30), G2-PUI (n=30) and the positive control group (n=4). Removal procedure consisted of three repeated one-minute-cycles. Samples were split longitudinally, photos of halves were taken at X6.4 magnification and were analyzed using the ImageJ-Software (The National Institutes of Health NIH, Bethesda, Maryland, USA) to calculate the percentage of surfaces with residual Ca(OH)2; the results were compared using the Wilcoxon-Mann Whitney test. Photos of the apical thirds were taken at X16 and X40 magnifications and were scored by two examiners from (0) to (4). Scores of the apical third were compared using the Fisher test. The Xp-endo Finisher removed completely the Ca(OH)2 dressing from four teeth (13.33%) whereas the PUI in one tooth (3.33%). The mean values of the remaining Ca(OH)2 were (2.1%, 3.6%) respectively and the difference was not significant (p= 0.195). Both examiners found the Xp-endo Finisher more efficient in the apical third and the difference was significant; p= (0.025, 0.047) respectively. The Xp-endo Finisher showed a superiority over the PUI in removing the Ca(OH)2 from the apical third after 3 minutes of activation

The Effects of Sodium Hypochlorite on Organic Matters: Influences of Concentration, Renewal Frequency and Contact Area

Introduction: Sodium hypochlorite (NaOCl) reacts mainly with proteins and its effectiveness depends on the substances chemical reactivity. It has been reported that volume, concentration, renewal, time, temperature and contact area affect the diffusion of NaOCl in the root canal. However, the relationship between some of these factors is not clear. The purpose of this study was to test the effect of volume, contact area, concentration and renewal frequency of 2.5% and 9.8% NaOCl solutions   on their organic matter dissolving-capacity. Methods and Materials: Pieces of gelatine (18% w/v) with standardized weight, form and structure were either fully or partially exposed to a 2.5% or 9.8% NaOCl solution. In three successive studies, biological dissolution-capacity of NaOCl was tested under different conditions. In experiment 1 the effect of volume/time, in experiment 2 the time/concentration/renewal frequency and in experiment 3 the contact area/renewal frequency/concentration/time of 2.5% or 9.8% NaOCl solutions on dissolving-capacity of organic matter were studied. The weight loss of gelatine pieces over time was registered. The non-parametric tests of Mann-Whitney and Kruskal-Wallis at the 5% threshold were used for statistical analysis. Results: The differences between the two concentrations of NaOCl solution (2.5% and 9.8%) are statistically significant in the effects of different volumes on total dissolution time (P<0.05). Differences in weight loss according to the concentration of the NaOCl solution used (2.5% or 9.8%) were significant after 2 min of contact time (P<0.05). Differences in weight loss between the model and the tube are significant (P<0.05) when the solution is repeated every 30 sec and every 1 min after 2 min of contact. Conclusion: This in vitro study showed that   using a more concentrated NaOCl solution would certainly improve the endodontic disinfection, but the biological risk in case of apical extrusion should be considered.Keywords: Concentration; Dosage; Gelatine; Root Canal Irrigant; Sodium Hypochlorit

Effect of Sodium Hypochlorite Concentration on Electronic Apex Locator Reliability

This ex vivo study aimed to measure the performance of an electronic apex locator (EAL) in the presence of sodium hypochlorite irrigants with different concentrations. Two EALs (Root ZX Mini and Locapex 6) were used to locate the apical foramen in 10 extracted single-rooted teeth in the presence of 0.5%, 2.5% and 5% sodium hypochlorite. Visual working lengths were also determined using #10 K-file under a microscope before the electronic measurements were made. The performance of both EALs was compared for the electronic working lengths determined under the different concentrations of sodium hypochlorite. A multiple-way ANOVA and PLSD Fisher’s test with an α risk fixed at 5% were conducted. There were no statistical differences in the working lengths determined by both EALs between the three groups with different concentrations of sodium hypochlorite and their visual control measurements. When a ± 0.5 mm margin was applied, the Root ZX Mini and the Locapex 6 presented 88% and 83% accuracy, respectively. Sodium hypochlorite concentration in irrigants does not affect the accuracy and reliability of either the Root ZX Mini or the Locapex 6. Electronic apex locators are reliable with any concentration of sodium hypochlorite irrigants

Utilisation en rotation continue des instruments de préparation canalaire en nickel-titane (évaluation des contraintes)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Les ciments de scellement canalaire (étude au microscope électronique à balayage de la pénétration tubulaire)

L'obturation canalaire est réalisée par l'association d'un noyau dur semi solide, la gutta-percha, à un ciment de scellement assurant l'étanchéité de l'obturation. Dans une première partie, l'auteur présente des rappels histo-anatomiques, les différents facteurs d'étanchéité d'une obturation, les propriétés idéales ainsi que les divers types de ciments canalaires. Dans une deuxième partie expérimentale, l'auteur étudie au microscope électronique à balayage la pénétration tubulaire de cinq ciments : Acroseal®, AH Plus®, Endobtur®, Kétac-Endo® et RSA®.TOULOUSE3-BU Santé-Centrale (315552105) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Obturation canalaire (les ciments de scellement)

TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Endodontie et tomographie volumique à faisceau conique (exploration détaillée de l'anatomie canalaire par le 9000 3d ® de Kodak)

Le succès de la thérapeutique endodontique dépend grandement de la connaissance de l'anatomie canalaire. Cependant, les chirurgiens dentistes n'ont à leur disposition aucun outil permettant la réalisation de son étude exhaustive. Récemment, le développement des systèmes de radiographie à faisceau conique a considérablement améliorer les possibilités d'imagerie de la région maxillo-faciale. Le but de notre thèse est donc d'évaluer la capacité et la précision d'un appareil de tomographie volumique, le 9000 3D ® de Kodak, pour détailler l'anatomie endodontique. Afin de répondre à cet objectif, nous avons réalisé sur 14 canaux de dents extraites, une étude comparative entre des reconstructions cC et les images numérisées de sections canalaires correspondantes.TOULOUSE3-BU Santé-Centrale (315552105) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Impacts bucco-dentaires de la pratique intensive d'un sport en piscine

TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF