Background: Complete seal of the root canal system following its chemo-mechanical debridement plays a pivotal role for achieving successful endodontic treatment. This can be established by reducing the gaps between the core filling material and root canal wall. Aim: To assess and compare the dislocation resistance of root canals obturated with GuttaFusion® and TotalFill BC sealer versus single cone obturation technique and TotalFill BC sealer after instrumentation of the canals with WaveOne, ProTaper Next and ProTaper Universal system. Material and Method: Sixty extracted human permanent mandibular premolars were conducted in the current study. The teeth were decorated and left the root with 15mm length; the roots were divided randomly into three main groups, twenty roots in each group. The roots were instrumented with different rotary systems using crown down technique according to the groups: (Group I) was instrumented with WaveOne files. (Group II) was instrumented with ProTaper Next system and (Group III) was instrumented with ProTaper Universal system. For each group the same irrigation regimen was used, 3 mL of 5.25% sodium hypochlorite and 3 mL of 17% EDTA to remove the smear layer. Then, Group I was also subdivided randomly into two subgroups of ten samples each, (Group I A) obturated with single cone gutta-percha and (Group I B) filled with GuttaFusion®. Group II was divided into (Group II A) obturated with single cone gutta-percha and (Group II B) filled with GuttaFusion®. Group III was divided into (Group III A) obturated with single cone gutta-percha and (Group III B) obturated with GuttaFusion®. In the present study, TotalFill BC sealer was used for all the tested groups. Then, the roots were embedded in clear acrylic resin and each root sectioned into three sections of 2mm thick (apical, middle and coronal). The push-out bond strength values represented by (MPa) unit was calculated by dividing the load on the surface area and the last was measured in collaboration with AutoCAD system software program. Failure mode analysis was carried out to examine the type of failure in each sample by using a stereomicroscope. Results: The results showed highly significant differences among the main groups that instrumented with different rotary systems (WaveOne, ProTaper Next and ProTaper Universal system). There were highly significant differences between the two obturation techniques of the subgroups (single cone gutta-percha versus GuttaFusion®). However; Gutta-Fusion® showed highest bond strength value than single cone obturation technique. The coronal third slices of all groups showed highest value of bond strength in comparison to the middle thirds and apical thirds. In the meantime, the middle third slices showed bond strength higher than that of the apical thirds for all groups. Statistical analysis was performed by using two way ANOVA and LSD tests. Conclusions: The instrumentation techniques and the obturation materials significantly affected the push-out bond strength values of obturation system. The highest value was appointed in root canals instrumented with ProTaper Universal System; obturated with GuttaFusion® and BC sealer, whereas, the lowest bond strength was appeared at canals instrumented with ProTaper Next; obturated with single cone gutta-percha and BC sealer.
The lead-acid battery has become so dependable in its used applications of automobile starting, emergency lighting and telecommunications, which left an impression that no further investigation is necessary or desirable. While there has been slow continuous improvements in lead-acid battery performance and mainly limited to design and material engineering. This work is mainly devoted to the properties of the active mass of the positive electrode and the acid/water ratio during the manufacturing process. A field study is carried out at the State Battery Manufacturing Company located in Baghdad, to prepare batches of lead mono-oxide with predefined quantities of liquid additives (i.e. sulfuric acid and water). Quality control and laborator
... Show MoreIn this study, the effect of pumping power on the conversion efficiency of nonlinear crystal (KTP) was investigated using laser pump-power technique. The results showed that the higher the pumping power values, the greater the conversion efficiency (η) and, as the crystal thickness increases within limitations, the energy conversion efficiency increases at delay time of (0.333 ns) and at room temperature. Efficiency of 80% at length of KTP crystal (L = 1.75 X 10-3 m) and Pin = 28MW, and also, compare the experimental results with numerical results by using MATLAB program.
The paper shows how to estimate the three parameters of the generalized exponential Rayleigh distribution by utilizing the three estimation methods, namely, the moment employing estimation method (MEM), ordinary least squares estimation method (OLSEM), and maximum entropy estimation method (MEEM). The simulation technique is used for all these estimation methods to find the parameters for the generalized exponential Rayleigh distribution. In order to find the best method, we use the mean squares error criterion. Finally, in order to extract the experimental results, one of object oriented programming languages visual basic. net was used
Research summary
Perhaps the methods of mask that Arab poets resorted to in our time are due to the conditions of oppression and political and social repression that the Arab poet suffered from; So he strived to circumvent it, and it became a justification for hiding behind it. The research is available on a number of topics that lead to the definition of the mask technique and the beginning of its prevalence in Arabic literature after the Second World War, especially in recent decades by benefiting from historical stories, fairy tales and legends of all kinds. As well as defining the mask idiomatically and linguistically, and the beginning of its use in ancient religious rituals, and the special place it had in Greek plays. Poets
... Show MoreThe letters are exposed in some texts of the classical Arabic language (poetry or prose), or in some of the Qur’anic texts, which are the main sources that were adopted on the day when provisions, rules and linguistic controls were established. I say that some of these letters are exposed in some contexts to deletion, mention, or change in the structure and shape of the letter. As for the omission, it is one of the aspects that distinguished Arabic, as well as other languages, for many purposes that differ among their user.
The magnetic properties of a pure Nickel metal and Nickel-Zinc-Manganese ferrites having the chemical formula Ni0.1(Zn0.4Mn0.6)0.9Fe2O4 were studied. The phase formation and crystal structure was studied by using x-ray diffraction which confirmed the formation of pure single spinel cubic phase with space group (Fd3m) in the ferrite. The samples microstructure was studied with scanning electron microstructure and EDX. The magnetic properties of the ferrite and nickel metal were characterized by using a laboratory setup with a magnetic field in the range from 0-500 G. The ferrite showed perfect soft spinel phase behavior while the nickel sample showed higher magnetic loss an
... Show MoreIn this work, two cone-inverted cylindrical and cross-hybrid dielectric resonator antennas are stacked and excited by the coaxial probe method with an operating standard resonant frequency of 5.438 GHz. A drawback of these standard Dielectric Resonator Antennas (DRAs) is their narrow bandwidth. For good antenna performance, a stacked DR geometry and a thick dielectric substrate having a low dielectric constant are desired since this provides large bandwidth, better radiation power, reduces conductor loss and nonappearance of surface waves. Many approaches, such as changing the shape of the dielectric resonator, have been used to enhance bandwidth. Using DRA, having the lowest dielectric constant, increases the bandwidth and the electroma
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