Background: In capturing a negative image, the digital impression secures a digital record for the purposeof designing and creating restorations. The introduction of scanning system presents a paradigm shift in the way of the dental impression procedure and encourages the accuracy of obtained restoration especially in the marginal area as a result of producing accurate final impression The digital system offers many advantages over the Conventional method.. The objective of this present in vitro study was to evaluate the marginal fitness of all ceramic crowns fabricated by direct digital scanning of the prepared tooth using two types of intra-oral cameras (Bluecam camera with strip light projection technique and Omnicam camera with video sampling technique). Materials and Methods: Sixteen sound upper first premolar teeth of comparable size were collected. Standardized preparation of all teeth samples were carried out to receive all ceramic crown restoration with deep chamfer finishing line (1mm), axial length (4mm) and convergence angle (6â—¦). The specimens divided in to two groups according to the type of digital impression technique: Group A, eight prepared teeth scanned directly by Bluecam camera; Group B, eight prepared teeth scanned directly by Omnicam camera. Then CAD/CAM all ceramic crowns constructed for each tooth sample. Marginal discrepancy was measured at Sixteen points per tooth using digital microscope at (120X) magnification. Results: Independent sample t-test was used to identify and localize the source of difference among the groups. It was found that there is statistically non- significant difference in the marginal gap mean values between (group A and group B). Conclusions: From the above result we can conclude that the two types of direct digitization techniques have the same accuracy.
In this research constructed N2 laser system by use developed method of electric discharge. In this method used four step of electric discharge by using four capacitors, three spark gaps, high tension power supply varying in range from 12kV to 24 kV and three resistors, this method called three stage blumlein circuit. The breakdown time delay of these parallel spark gaps cement strong ultraviolet preionization in the laser channel, thus the result of these amendments the laser output is many doubled and is more increasing than that obtained using the one and two stage blumlein circuits. This system has been designed and operated to give pulse laser with wavelength at 337.1 nm. This laser system can operate without mirrors and optical res
... Show MoreThis project sought to fabricate a flexible gas sensor based on a short functionalized multi-walled carbon nanotubes (f-MWCNTs) network for nitrogen dioxide gas detection. The network was prepared by filtration from the suspension (FFS) method and modified by coating with a layer of polypyrrole conductive polymer (PPy) prepared by the oxidative chemical polymerization to improve the properties of the network. The structural, optical, and morphological properties of the f-MWCNTs and f-MWCNTs/PPy network were studied using X-ray diffraction (XRD), Fourie-transform infrared (FTIR), with an AFM (atomic force microscopy). XRD proved that the structure of f-MWCNTs is unaffected by the synthesis procedure. The FTIR spectra verified the existence o
... Show MoreWe report on using a CO2 (10.6 µm) laser to debond the lithium disilicate veneers. Sixty-four sound human premolar teeth and 64 veneer specimens were used in the study. The zigzag movement via CO2 laser handpiece along with an air-cooled jet to prevent temperature elevation above the necrosis temperature limit (5.5 C°) was applied. The optimal deboning irradiation time was super-fast, at about 5 seconds at 3 Watt CO2 laser power. It is 20 times less than any previously published work for veneers debonding. The enamel beneath the debonded veneers has been assessed by atomic force microscopy (AFM) and shear stress technique as criteria for the easiness of debonding. The
... Show MoreMy research tagged [the lights of the statement in the first part of the Koran] came to show that the dear book was developed according to a precise linguistic system is not increased by a word or letter or movement - Aldmh and Kira and the hole - and does not lack anything of it except with the wisdom required by the meanings of the Koranic text or Sura generally . The Koran does not come falsehood from his hands or from behind it is infallible and preserved; because it was revealed by the sage Hamid Hamid ﭽﮗ ﮘ ﮙ ﮚ ﮛ ﮜ ﮝ ﮞ ﭼ [stone]. The Qur'an is safe from any verbal or moral dominance and dominates all the heavenly books and exists at any time and place that speaks the truth ﭽ ﯛ ﯜ ﯝ ﯞ ﯟ ﯹ ﯺﭼ [The
... Show MoreThe Turkish intervention in the Libyan crisis in the recent period was a trigger for more tension than a solution - as Turkey claims - as Turkey seeks to quickly set a welcome military footing in Libya to prevent the reconciliation government from falling and planning to start exploration for gas and oil in Libya to solve the Turkish energy crisis, that is, the energy exchange for security and trying to exploit the situation to establish a new gathering of proTurkish political Islam, as for the Iranian position on the Libyan crisis, it does not exceed a logistical role and provide Turkey with expertise in circumventing international sanctions and assisting it in transporting fighters and weapons to Libya, Iran has also deliberately added so
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