Background: The use of electronic apex locators for working length determination eliminates many of the problems associated with the radiographic measurements (interference of anatomical structures, errors in projection such as elongation or shortening, and lack of three-dimensional representation). Its most important advantage over radiography is that it measures the length of the root canal to the apical constriction, not to the radiographic apex. The aim of this study was to assess the accuracy of a new fifth generation apex locator (Joypex 5) in recording the apical constriction and comparing it with a third generation apex locator (Root ZX) in vitro. Materials and method: Twenty four single-rooted sound human premolars, extracted for the purpose of orthodontic treatment and with fully-formed roots, were used in this study. Endodontic access cavity was prepared in each tooth and canal patency up to the apical foramen was checked with a #15 stainless steel K-file. No root canal preparation was performed. Root canal length measurement was done directly and electronically using two apex locators (Joypex 5 and Root ZX). Direct measurement of the root canal length was done by introducing a #15 K-file inside the root canal until its tip was just visible at the apical foramen, then removed from the root canal and its length was measured (in mm) and subtracted by 0.5 mm. For electronic measurement, the teeth were fixed in a sponge soaked in saline and the root canals were also filled with saline. The lip electrode was attached to the sponge and the apex locators were used according to the manufacturers' instructions. The file holder was clipped to the metal shaft of a #15 K-file and the file was then inserted inside the root canal and advanced until the display reading on the LCD of the apex locator was "0.5". The file was then removed from the root canal and its length was measured (in mm). The differences between the readings of each apex locator and the actual length of each canal were computed, and the results were analyzed statistically by paired t-test using SPSS Version 13. Results: The results of this study showed that the Joypex 5 apex locator showed a lower mean difference than the Root ZX apex locator as compared with the actual length, which was statistically significant (p<0.05). Concerning the accuracy of the two apex locators, Joypex 5 apex locator recorded the apical constriction exactly in 67%, while the Root ZX apex locator in only 25%. Within ±0.5 mm from the actual length, the accuracy of the Joypex 5 and the Root ZX were 83% and 67%, respectively. Within ±1 mm from the actual length, the accuracy of the Joypex 5 and the Root ZX were 100% and 96%, respectively. Conclusion: The Joypex 5 apex locator which is a fifth generation apex locator was more accurate in recording the apical constriction as compared with the Root ZX apex locator which is a third generation apex locator.
Background: Pit and fissure sealant have been considered an outstanding adjunct to oral health care in the decrease of occlusal caries onset and low progression. The aims of this in vitro study were to evaluate the marginal microleakage of three different types of fissure sealants (SDI, Tg and tetric N-flow) by time interval, one day and 45 days, in the presence or absence of bonding agent among maxillary and mandibular teeth. Materials and methods: Seventy two sound human maxillary and mandibular first premolar teeth were collected which were free from obvious carious lesions. The teeth were randomly divided into two main equal groups, group (1) and group (2), each group consists of (36) teeth involving equal numbers of maxillary and mandi
... Show MoreIn his masterpiece ’The Prophet’, Kahlil Gibran presents his unwavering faith and passionate belief in the healing power of universal love that brings humans to sublime ideas and elevates their souls and behavior. The current study aims to find out the stylistic devices utilized to represent the concept of love based on the hypothesis that Gibran tends to use certain stylistic effects to convey his meaning. The study adopts Leech and Short’s (2007) framework of stylistic analysis to analyze the lexical items and figures of speech in selected extracts from the book. The findings reveal that Gibran prefers concrete nouns, dynamic verbs, and physical adjectives over abstract nouns, stative verbs, and psychological adjectives to s
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Due to severe scouring, many bridges failed worldwide. Therefore, the safety of the existing bridge (after contrition) mainly depends on the continuous monitoring of local scour at the substructure. However, the bridge's safety before construction mainly depends on the consideration of local scour estimation at the bridge substructure. Estimating the local scour at the bridge piers is usually done using the available formulae. Almost all the formulae used in estimating local scour at the bridge piers were derived from laboratory data. It is essential to test the performance of proposed local scour formulae using field data. In this study, the performance of selected bridge scours estimation formulae was validated and sta
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(2)
Trip generation is the first phase in the travel forecasting process. It involves the estimation of the
total number of trips entering or leaving a parcel of land per time period (usually on a daily basis);
as a function of the socioeconomic, locational, and land-use characteristics of the parcel.
The objective of this study is to develop statistical models to predict trips production volumes for a
proper target year. Non-motorized trips are considered in the modeling process. Traditional method
to forecast the trip generation volume according to trip rate, based on family type is proposed in
this study. Families are classified by three characteristics of population social class, income, and
number of vehicle ownersh
(4)
The risk assessment for three pipelines belonging to the Basra Oil Company (X1, X2, X3), to develop an appropriate risk mitigation plan for each pipeline to address all high risks. Corrosion risks were assessed using a 5 * 5 matrix. Now, the risk assessment for X1 showed that the POF for internal corrosion is 5, which means that its risk is high due to salinity and the presence of CO, H2S and POF for external corrosion is 1 less than the corrosion, while for Flowline X2 the probability of internal corrosion is 4 and external is 4 because there is no Cathodic protection applied due to CO2, H2S and Flowline X3 have 8 leaks due to internal corrosion so the hazard rating was very high 5 and could be due to salinity, CO2, fluid flow rate
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The design of safe pedestrian facilities usually depends on the assessment of pedestrian characteristics and behavior. In this investigation, pedestrian walking speed through the religious occasion have been monitored at three locations, Al- Kadhimiya (Imam AL-Kadim), Najaf and Karbala (Imam AL-Husain) holy shrines. Video captures of the pedestrian through their walking to the two holy shrines have been prepared and analyzed for walking speed, gender, age groups, and clothing tradition. The pedestrian sample size is 468, 501, and 447 for Al- Kadhimiya, Karbala, and Najaf respectively. When the gender is taken into consideration, it can be noted that the walking speed of male and female pedestrian is (0.97, 1.68, and 1.63
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The importance of Baghdad city as the capital of Iraq and the center of the attention of delegations because of its long history is essential to preserve its environment. This is achieved through the integrated management of municipal solid waste since this is only possible by knowing the quantities produced by the population on a daily basis. This study focused to predicate the amount of municipal solid waste generated in Karkh and Rusafa separately, in addition to the quantity produced in Baghdad, using IBM SPSS 23 software. Results that showed the average generation rates of domestic solid waste in Rusafa side was higher than that of Al-Karkh side because Rusafa side has higher population density than Al-Karkh side. T
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(3)
In recent years and decades, there is a great need for developing new alternative energy sources or renewable sustainable energy. On the other hand, new technology approaches are growing . towards benefits from the valuable nutrients in wastewater which are unrecoverable by traditional wastewater treatment processes. In the current study, a novel integrated system of microbial fuel cell and anoxic bioreactor (MFC-ANB) was designed and constructed to investigate its potential for slaughterhouses wastewater treatment, nitrogen recovery, and power generation. The system consisted of a double-chamber tubular type MFC with biocathode inoculated with freshly collected activated sludge. The MFC-ANB system was continuously fed with real-fi
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