Background: The aims of the study were to evaluate the unclean/clean root canal surface areas with a histopathological cross section view of the root canal and the isthmus and to evaluate the efficiency of instrumentation to the isthmus using different rotary instrumentation techniques. Materials and Methods:The mesial roots of thirty human mandibular molars were divided into six groups, each group was composed of five roots (10 root canals)which prepared and irrigated as: Group one A: Protaper system to size F2 and hypodermic syringe, Group one B: Protaper system to size F2 and endoactivator system, Group two A:Wave One small then primary file and hypodermic syringe, Group two B:Wave One small then primary file and endoactivator system, Group three A: step back technique to size 25 file as MAFand hypodermic syringe, Group three B: step back technique to size 25 file as MAFand endoactivator system . All the roots were sectioned at 2mm, 6mm ,12mm from the apex and studied by histopathological cross section. The degree of cleaning of each section was measured by the use of Autocade 2004 software system. Result :the least uncleaned isthmus surface area at coronal, middle and apical section was found by the Protaper system with endoactivator which represented the mean of the percentage of uncleaned surface area of 16.87%, 14.32% and 9.55% respectively. The system that produced least uncleaned canal wall was by Protaper system with endoactivator at coronal ,middle ,and apical sections of 12.21%, 9.14% and 18.55% respectively . The mean of highest percentage of increased canal diameter which was Protaper system, Wave One system and then step back. The comparison between the groups in the means which showed that the highest percentage of decrease in isthmus area was with the Protaper system, Wave One system and lastly the step back. Conclusions:The Protaper system with endoactivator was the best system in canal and isthmus cleaning.
Aim: The reduction in the amount of marginal bone is the most important demand for the long term success of dental implants. This prospective clinical study was aimed to investigate the marginal bone loss of early loaded SLActive implants with different dimensions and surgical approaches. Materials and methods Fifteen patients aged from 18 to 60 years were divided into 2 groups (flapped and flapless approach) that underwent delayed implant placement protocol with SLActive implants. The marginal bone level was estimated by cone-beam computed tomography during three different periods: preoperatively, 8 weeks after surgery and 24 weeks after loading of the prosthesis. Results: The mean value of marginal bone level was not significantly chan
... Show MoreBackground: Elastomeric chains are one of the most commonly used force delivery systems. They have the ability to exert a continuous force, convenience of use, compatibility to oral environment and cost effectiveness but one of the inherited disadvantages is force degradation. Materials and methods: This in vitro study was designed to evaluate the effect of alcohol presence in mouthwashes on force decay of different configurations of clear elastomeric chains from (Ortho Technology company) which are: closed , short and long under the effect of time at (Initial, 1, 2, 3 and 4 weeks) intervals with exposure to different chemical solutions. A total (540) modules of elastomeric chains of three different types (long, short and closed) trans
... Show MoreGlobal Navigation Satellite System (GNSS) is considered to be one of the most crucial tools for different applications, i.e. transportation, geographic information systems, mobile satellite communications, and others. Without a doubt, the GNSS has been widely employed for different scientific applications, such as land surveying, mapping, and precise monitoring for huge structures, etc. Thus, an intense competitive has appeared between companies which produce geodetic GNSS hardware devices to meet all the requirements of GNSS communities. This study aims to assess the performance of different GNSS receivers to provide reliable positions. In this study, three different receivers, which are produced by different manufacturers, were fi
... Show MoreGlobal Navigation Satellite System (GNSS) is considered to be one of the most crucial tools for different applications, i.e. transportation, geographic information systems, mobile satellite communications, and others. Without a doubt, the GNSS has been widely employed for different scientific applications, such as land surveying, mapping, and precise monitoring for huge structures, etc. Thus, an intense competitive has appeared between companies which produce geodetic GNSS hardware devices to meet all the requirements of GNSS communities. This study aims to assess the performance of different GNSS receivers to provide reliable positions. In this study, three different receivers, which are produced by different manufactur
... Show MoreThe efficient behavior of a low-concentrating photovoltaic-thermal system with a micro-jet channel (LCPV/T-JET) and booster mirror reflector is experimentally evaluated here. Micro-jets promote the thermal management of PV solar cells by implementing jet water as active cooling, which is still in the early stages of development. The booster mirror reflector concentrates solar irradiance into solar cells and improves the thermal, electrical, and combined efficiencies of the LCPV/T-JET system. The LCPV/T-JET system was tested under ambient weather conditions in the city of Bangi, Selangor, Malaysia, and all data was recorded between 10:00 a.m. and 4:00 p.m. Parametric studies were conducted to compare the performance of the LCPV/T-JET system
... Show MoreBackground: This study was conducted to assess the effects of various beverages on the shear bond strength of light-cured orthodontic composite used to bond stainless steel orthodontic brackets on human teeth and to determine the site of bonding failure of this material. Materials and Methods: Fifty extracted human premolars were selected and randomly divided into five equal groups each with 10 teeth according to the beverage type (Control, One Tiger, Milk, Green tea and Coffee). After bonding, the teeth were immersed in specific beverages for 5 minutes twice daily with equal intervening intervals then washed and stored in distilled water at 37º C for the reminder of the day. The process was carried out for 30 days. The samples were then
... Show MoreThe goal of this experimental study is to determine the effects of different parameters (Flow rate, cuttings density, cuttings size, and hole inclination degree) on hole cleaning efficiency. Freshwater was used as a drilling fluid in this experiment. The experiments were conducted by using flow loop consist of approximately 14 m (46 ft) long with transparent glass test section of 3m (9.84 ft.) long with 4 inches (101.6 mm) ID, the inner metal drill pipe with 2 inches (50.8 mm) OD settled with eccentric position positive 0.5. The results obtained from this study show that the hole cleanings efficiency become better with high flow rate (21 m3/hr) and it increase as the hole inclination angles increased from 60 to 90 degree due to dominated
... Show MoreThe evaluation and efficiency and effectiveness of account system for the department of delegation and cultural Relationships in the center of ministry of higher Education and Scientific research Considered as a very important and active subjects in the modification of accounting system in this department and to develop it and make it able to make available important and accurate information for the planning requirements and monetary and evaluation performance and to make decisions, besides to develop the performance of Iraqi Cultural departments working abroad and to render its role effective to serve the students of higher education in the progressive Countries to facility its growing in scientific and professional and technica
... Show MoreThe aim of this study is to investigate the nature of the relationship between domestic savings and domestic investment, or rather the efficiency of domestic savings in financing development in Algeria, in order to explain this relationship, identify the challenges to investment, and finance and accelerate economic growth. The economic measurement methodology has estimated the relationship between the savings rate and the local investment rate in the Algerian economy. We have annual data for the period 1970-2014. One of the most important conclusions is that there is no relationship between savings and investment, nor even an integration between them. To illustrate this, the use of some statistical tools, a
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