Evaluation of three instrumentation techniques at the precision of apical stop and apical sealing of obturation

OBJECTIVE: The aim of this study was to investigate the ability of two NiTi rotary apical preparation techniques used with an electronic apex locator-integrated endodontic motor and a manual technique to create an apical stop at a predetermined level (0.5 mm short of the apical foramen) in teeth with disrupted apical constriction, and to evaluate microleakage following obturation in such prepared teeth. MATERIAL AND METHODS: 85 intact human mandibular permanent incisors with single root canal were accessed and the apical constriction was disrupted using a #25 K-file. The teeth were embedded in alginate and instrumented to #40 using rotary Lightspeed or S-Apex techniques or stainless-steel K-files. Distance between the apical foramen and the created apical stop was measured to an accuracy of 0.01 mm. In another set of instrumented teeth, root canals were obturated using gutta-percha and sealer, and leakage was tested at 1 week and 3 months using a fluid filtration device. RESULTS: All techniques performed slightly short of the predetermined level. Closest preparation to the predetermined level was with the manual technique and the farthest was with S-Apex. A significant difference was found between the performances of these two techniques (

Salivary changes and dental caries as potential oral markers of autoimmune salivary gland dysfunction in primary Sjögren's syndrome

BACKGROUND: the classification criteria for primary Sjögren's syndrome (pSS) include a number of oral components. In this study we evaluated if salivary flow and composition as well as dental caries are oral markers of disease severity in pSS. METHODS: in 20 patients fulfilling the American-European Consensus criteria for pSS and 20 age-matched healthy controls whole and parotid saliva flow rates and composition, measures of oral dryness, scores of decayed, missing and filled tooth surfaces (DMFS), periodontal indices, oral hygiene, and dietary habits were examined. RESULTS: in pSS, salivary flow rates, pH, and buffer capacities were lower, and DMFS, salivary sodium and chloride concentrations higher than in the healthy controls. DMFS also correlated inversely to salivary flow rates and positively to oral dryness. Apart from slightly increased gingival index, and more frequent dental visits in pSS, the periodontal condition, oral hygiene or sugar intake did not differ between these two groups. In pSS, findings were correlated to labial salivary gland focus score (FS) and presence of serum-autoantibodies to SSA/SSB (AB). The patients having both presence of AB and the highest FS (>2) also had the highest salivary sodium and chloride concentrations, the lowest salivary phosphate concentrations, lowest salivary flow rates, and highest DMFS compared to those with normal salivary concentrations of sodium and chloride at a given flow rate. CONCLUSION: the salivary changes observed in some pSS patients reflect impaired ductal salt reabsorption, but unaffected acinar transport mechanisms, despite low salivary secretion. Our results suggest that changes in salivary flow and composition as well as dental caries may serve as potential markers of the extent of autoimmune-mediated salivary gland dysfunction in pSS. The study also indicates that the ductal epithelium is functionally affected in some pSS patients, which calls for future pathophysiological studies on the mechanisms underlying this impaired salt reabsorption

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Étudier ensemble les cornes et les plumes tient quelque peu de la gageure : après le miroir et les clefs le séminaire du CETM s'est en effet proposé d'étudier les représentations symboliques et les usages littéraires développés autour de ces deux éléments métonymiques initialement rattachés à l'animalité. Mais pourquoi les associer ? La corne terrestre et la plume aérienne ont chacune nourri un imaginaire propre, qu'on pourrait croire totalement opposé. Pourtant, elles sont parfois associées ..

Evaluation des dechets urbains et animaux comme sources de phosphore

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The impact of European integration on Scottish devolution

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Influence du poids de la semence et de la profondeur de semis sur la croissance et le développement de la plantule de maïs

National audienceGrowth and development of maize seedlings according to seed weight, depth of sowing and variety (4) were studied in a greenhouse. Up to 240° per d, the growth of the DEA variety is directly proportional to the amount of seed reserves which have been used since germination: the ratio shows little variation according to seed weight and sowing depth (the variation coefficient is 3.1 %, figs 1 and 2). The slight advantage of seedlings originating from light seeds in relation to the relative amount of reserves which have been utilized during a given period of time (table I) is quite insufficient to counterbalance the much larger absolute amount used from heavy seeds. As a consequence, the seedlings originating from heavy seeds displayed rapid growth (fig 3). We found a genetical variation in the rhythm of seed reserves utilisation as follows: Monarque was more rapid, followed by DEA, F7 x F2 then Mohican (table V). These differences have consequences on the rate of growth during the heterotrophic stage, which is higher with Monarque. Unlike the growth, the development (appearance of new organs as leaves or ramifications on the radicle or lateral roots) is independent of the weight of the originating seed. It expresses the physiological age of the seedling, according to the time passed, as the sum of temperature (table II). The ratio of reserves used when a seedling starts an autotrophic life is about 65%, showing little variation. At that time, seedlings have passed the 3rd leaf stage, the advent of ramifications on lateral roots, and we observe a temporary decrease in root weight as described by Bourdu and Gregory (1983) (table III). On the deep sowing treatments, the seedlings use seed reserves more rapidly and as a consequence of this, grow faster (table IV). In these situations the emergence is comparatively delayed with shallow sowings, but this difference of stage disappears after the advent of the 1st leaf. When the ermergence takes place, the seedlings originating from light seeds sowed deeply dispose of only 45% of maternal reserves (ie 75 mg) in contrast with those from heavy seeds and shallow sowing which still dispose of 71% (ie 235 mg). In the first situation, the safety margins, in the event of adverse conditions (cold weather, excess of water, coarse seed-bed, surface crust) are restricted. On the other hand, the weight of chlorophyllian organs, when efficient photosynthesis takes place, is much higher in seedlings originating from heavy seeds rather than from light seeds: the initial state of the exponential growth is much better, and, as a consequence, this fact could induce better progress at all stages.On a étudié, en conditions semi-contrôlées sous serre, la croissance et le développement de plantules de maïs selon le poids de la semence, la profondeur de semis et la variété (4). Pendant la phase hétérotrophe, la croissance de l’hydride DEA est, à peu de choses près, directement proportionnelle à la quantité de réserves de la graine utilisées depuis la germination, dans un rapport peu variable suivant les conditions (coefficient de variation de 3,1%). Les plantules issues de grosses semences présentent une croissance nettement plus rapide, mais une efficience légèrement moindre pour l’utilisation des réserves de la graine. Les stades foliaires ou racinaires sont déterminés par l’âge de la plantule depuis sa germination, indépendamment de la taille de la semence d’origine, et, après l’apparition de la 2e feuille, indépendamment de la profondeur de semis. Les plantules issues de semis profonds utilisent un peu plus rapidement les réserves de la semence et montrent un taux de croissance supérieur. La fraction des réserves mobilisées jusqu’au passage à l’autotrophie est peu variable, autour de 65% : les plantules issues de grosses semences débutent donc leur période photosynthétique avec une plus grande quantité de réserves encore disponibles dans la semence et avec un poids supérieur d’organes chlorophylliens