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.
Abstract
The research Compared two methods for estimating fourparametersof the compound exponential Weibull - Poisson distribution which are the maximum likelihood method and the Downhill Simplex algorithm. Depending on two data cases, the first one assumed the original data (Non-polluting), while the second one assumeddata contamination. Simulation experimentswere conducted for different sample sizes and initial values of parameters and under different levels of contamination. Downhill Simplex algorithm was found to be the best method for in the estimation of the parameters, the probability function and the reliability function of the compound distribution in cases of natural and contaminateddata.
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In IRAQ, the air conditioners are the principal cause of high electrical demand. In summer, the outer temperature sometimes exceeds 500C which significantly effects on the A/C system performance and power consumed. In the present work, the improvement in mechanical and electrical performance of split A/C system is investigated experimentally and analytically. In this paper, performance and energy saving enhancement of a split-A/C system was experimentally investigated to be efficiently compatible with elevated temperature weathers. This improvement is accomplished via Smart Control System integrate with Proportional-Integral- Differential PID algorithm. The PIC16F877A micro-controller has been programmed with the PID and PWM c
... Show MoreAmaranthus viridis L. belongs to the Amaranthaceae family. It is a rich source of numerous phytochemicals and amino acids. The objective of this work was to optimize Ultrasound-Assisted Extraction (UAE) based on the extraction yield and Thin-Layer Chromatography (TLC) profile under different conditions, to compare the optimized UAE to the Soxhlet extraction method and evaluate the cytotoxic effects of the ethyl acetate fraction of the 80 % ethanolic extract on the SKGT-4 (human esophageal adenocarcinoma), AGS (human gastric adenocarcinoma) and A431 (human epidermoid carcinoma). A one-factor at a time experiment was carefully designed to assess the influence of the following factors on the extraction: time, frequency, solid-to-solven
... Show MoreThe study aimed to identify how to raise grateful children from an Islamic educational perspective. For that objective to be achieved, the researcher used both of deductive and descriptive approaches using the method of documentary research. The study's results show that children are the real wealth of the community and the foundation of cultural building; therefore, paying attention their raising is a responsibility that must be shared by everyone; gratitude is part parcel of the Islamic doctrine, which is one of the greatest virtues; the virtue of gratitude is the attitude of the believers which in turn strengthens the bonds and expands the network of positive social relationships; It is also considered a cultural significance
... Show MoreStatistical learning theory serves as the foundational bedrock of Machine learning (ML), which in turn represents the backbone of artificial intelligence, ushering in innovative solutions for real-world challenges. Its origins can be linked to the point where statistics and the field of computing meet, evolving into a distinct scientific discipline. Machine learning can be distinguished by its fundamental branches, encompassing supervised learning, unsupervised learning, semi-supervised learning, and reinforcement learning. Within this tapestry, supervised learning takes center stage, divided in two fundamental forms: classification and regression. Regression is tailored for continuous outcomes, while classification specializes in c
... Show MoreLiterary translation is one of the most difficult types of translation ,because it conveys feelings that differ from one person to another, and since the language constitutes an obstacle to understanding the Andalusian excerpts, the translators resorted to translating it, and this was a second start to the text, different from its first start, is said from the tongue of the Al-washah , The muwashshah is a poetic art that appeared in Andalusia after the Arabs entered it ,characterized by special system It differs from the traditional Arabic poem, as it has a beginning represented in the beginning of the muwashshah and several equal parts ending with differentrhymes.
... Show MoreThis study was carried out to determine the heavy metal accumulation of Juncus rigidus Desfontaines, 1798 from three different regions of the Basrah Province in Southern of Iraq. Specifically, the concentrations of lead, nickel, and cadmium were determined in the roots, culms and leaves of the plant. The results indicated that the highest accumulation of the heavy metal was recorded in lead (Pb) 12.50± 3.58 mg kg-1and then in nickel (< 0.30). The lowest value was recorded for cadmium (< 0.05). As well, lead concentrations in J. rigidus varied in different locations and parts of the plant from undetectable in control to 12.66, 19.33, and 9.80 mg kg-1 in leaves, culm, and roots respective
... Show MoreChronic Hepatitis B(CHB) is a serious sequel after Hepatitis B Virus infection, although the rate of chronicity is inverse with age but it may be associated with a significant proportion of deaths related to cirrhosis and liver cancer. HBV serology and measurement of hepatocytic enzymes with viral load can predict disease prognosis and response to treatment. HBeAg refers to a high viral replication and associated with more infectivity to others. This study aimed to determine the impact of HBeAg status in chronically infected patients on various baseline tests. A total of 90 patients with CHB infection who were included in this study. Several standardized measures used for liver function tests, viral load and hepatitis B serological
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