Background: Optimal root canal retreatment was required safe and efficient removal of filling material from root canal. The aim of this in vitro study was to compare the efficacy of reciprocating and continuous motion of four retreatment systems in removal of root canal filling material. Materials and Methods: Forty distal roots of the mandibular first molars teeth were used in this study, these roots were embedded in cold clear acrylic,roots were instrumented using crown down technique and rotary ProTaper systemize Sx to size F2 ,instrumentation were done with copiousirrigation of 2.5% sodium hypochlorite and 17% buffered solution of EDTA was used as final irrigant followed by distilledwater, roots were obturated with AH26 sealer and Protaper gutta-percha point F2 and medium fine accessory gutta-percha using lateral condensation technique,roots were left for 7 days with 100% humidity at 37ºC in an incubator. Roots were randomly divided into four groups according to technique used for removing the root filling material (ten teeth for each group): group I: reciprocating technique and Wave One system, group II: continuous technique and ProTaper retreatment system, group III: continuous technique and R-Endo system, group IV: continuous technique and D–RaCere treatment system. All the roots were radiographed before and after removal of gutta-percha from both bucco-lingual and mesiodistal directions using custom made platform and digital radiograph system RVG to havea digitized images. The total surface area of all root canals was measured before removal ofthe gutta-percha and the area of the remaining gutta-percha filling in the canals after retreatment procedure from both directions. These measurements were analyzed with Adobe Photoshop CS6 software, the percentage of removed gutta-percha calculated. Results: Statistical analysis was performed and the result showed group Ihad the highest mean values in removal of root canal filling material in both bucco-lingual and mesiodistal direction of dental radiograph and there were significant difference between group I and most of the other groups ,there were non significant difference between group II,group III and group IV. Conclusion: This study was showed all the used retreatment systems did notcompletely remove the root canal filling material. The reciprocating technique was most effective method for removing gutta-percha and sealer than continuous rotary technique. Key words: Retreatment, reciprocating motion, root canal filling, rotary instrument.
The aim of study was making comparison in some kinematics variables in (100) meter butterfly swimming to first and second ranking in championship 2003 Espana, so noticed there is no such like this study in our country in comparison study for international champions therefore not specific and scientific discovering to these advanced levels, also the researchers depend on group of kinematics variables when the comparison making and it was included (50 meter the first, 50 meter the second, the differences between the first (50) meter and the second , more over basic variables in (100) meter butterfly , after having the results and treat it statistically the researchers reaches to two conclusions which was: • Success the first rank in startin
... Show MoreWith the advancement of technology ,the study of cross-cultural communication via on line has become an important and researchable topic in linguistic theory and its applications.The aims of this study are two- fold (a) exploring the influence of cultural diversity on on-line interaction between American native speakers (NSs) and Iraqi non-native speakers (NNSs) of English which, together with other factors might potentially lead to what Thomas(1983) calls "pragmatic failure" (PF), a main cause of communication breakdowns and (b) specifying which type of PF occurs more frequently between the two groups along with the reasons behind such failures. To achie
... Show MoreWith the advancement of technology ,the study of cross-cultural communication via on line has become an important and researchable topic in linguistic theory and its applications.The aims of this study are two- fold (a) exploring the influence of cultural diversity on on-line interaction between American native speakers (NSs) and Iraqi non-native speakers (NNSs) of English which, together with other factors might potentially lead to what Thomas(1983) calls "pragmatic failure" (PF), a main cause of communication breakdowns and (b) specifying which type of PF occurs more frequently between the two groups along with the reasons behind such failures. To achieve these objectives , a number of online chats conducted between
... Show MoreIn the midst of political, cultural and economic fast developments accelerated, the world witnessed, with the accompanied big communication revolutions, many shapes of powers. Those developments were followed by changes in relations of international level.
The most prominent among those developments was the international public relations which became equal to official international relations. Moreover, the international public relations became a complementary element dur to the growth of public opinion and its affection on political regime. Such growth of public opinion pushed the politicians to address it; and try to gain its support.
The US was the first realized the importance of international public relations. Th
... Show MoreAmongst the literary writers who used their art to direct the attention towards the issue of woman and her rights in a proper life is the English poet and novelist Thomas Hardy (1840-1928), who has been praised for his “openness to the feminine principle” 1 as Irving Howe put it. Hardy’s wide readings have changed his way of dealing with and thinking about so many critical issues which started to float on the surface of the English society during the mid and late of the 19th century. His readings for a number of writers, who seem of huge impact on his writings as he later admits that – “[his] pages show harmony of view with
... Show MoreThe efficiency of egg yolk emulsion in coating DNA and its delivery across cellular membranes was evaluated in comparison with liposomes DOPE . The murine leukemia viral oncogene v-abl , cloned on pBR322 was used as a DNA substrate for direct injection into mice tissue . the DNA complexes were prepared by mixing the DNA with egg yolk emulsion and liposome . Each was directly injected into mice peritoneal cavity with proper control. The gene delivery was examined phenotypically by blood analysis and cytogenetic analysis . Chromosomal changes were detected in the bone marrow as from the fourth day post inoculation through the eleventh day when chromosomal ring s could be seen . this was accompanied by decrease in the WBC count ,
... Show MoreThe matter of handwritten text recognition is as yet a major challenge to mainstream researchers. A few ways deal with this challenge have been endeavored in the most recent years, for the most part concentrating on the English pre-printed or handwritten characters space. Consequently, the need to effort a research concerning to Arabic texts handwritten recognition. The Arabic handwriting presents unique technical difficulties because it is cursive, right to left in writing and the letters convert its shapes and structures when it is putted at initial, middle, isolation or at the end of words. In this study, the Arabic text recognition is developed and designed to recognize image of Arabic text/characters. The proposed model gets a single l
... Show MoreIn this paper, a novel flow control strategy which is the inlet throttled pump was used to design an angular velocity control system for rotary actuator. Inlet throttled systems have good performance in addition to their high efficiency compared to traditional valve controlled systems. The flow in the proposed system is adjusted by a valve that is positioned at the pump inlet with the purpose of reducing the energy loses across the valve. This regulated flow is used then to control the actuator angular velocity. The system was modeled and the open loop stability and performance were studied. In order to improve the system performance, Robust-Proportional-Integral-Derivative (RPID) and structured singular value (M@#@) controllers have been d
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