Background: White-spot lesion is one of the problems associated with the fixed orthodontic treatment. The aims of this in-vitro study were to investigate enamel damage depth on adhesive removal when the adhesive were surrounded by sound, demineralized or demineralized enamel that had been re-mineralized prior to adhesive removal using 10% Nano-Hydroxy apatite and to determine the effect of three different adhesive removal techniques. Materials and methods: Composite resin adhesive (3M Unitek) was bonded to 60 human upper premolars teeth which were randomly divided in to three groups each containing ten sound teeth and ten teeth with demineralized and re-mineralized lesions adjacent to the adhesive. A window of 2 mm was prepared on the buccal surface of the tooth and painted with an acid resistant nail varnish except for the window.The demineralized enamel produced by immersion of teeth in demineralization buffer for 12 days.half of the demineralized window, was covered with acid –resistant red nail varnish, and the samples were then subjected to re-mineralization with 10% of nano hydroxyapatite. The adhesive was removed with either :(1) fiber reinforced composite bur in slow speed handpiece (SS); (2)12 fluted long flame carbide bur in high speed handpiece (HS); (3) ultrasonic scaler (US).damage to the enamel was assessed using stereomicroscope with grid eye piece. Results: the greatest to least mean depth of damage with three different adhesive removal techniques to sound enamel was HS˃ US ˃SS and to demineralized and re-mineralized enamel were SS ˃US˃ HS. Sound enamel had the least amount of damage. Re mineralization before the adhesive removal highly significant reduced the amount of damage produced by all techniques compared with demineralized enamel. Conclusions: When the demineralized enamel was present 12 fluted long flame carbide bur were found to be the least damage in adhesive removal technique and re-mineralization further reduced the amount of enamel damage
Purpose: This study aimed to assess the thickness of alveolar bone of maxillary and mandibular incisors from orthodontics perspective. Materials and Method: A total of 73 Cone beam computed tomography for Iraqi patients (47 females and 26 males) were included in this study. The selected images were captured and imported to AutoCAD database software to perform the measurement. To measure alveolar bone thickness, a reference line was drawn through the long axis of each incisor, from the incisal edge to the root apex. Then, labial and lingual/palatal perpendicular lines were drawn to the reference line at 3, 6, and 9mm apically from the cemento-enamel junction (CEJ). Results: The buccal bone is generally thinner than the lingual/palata
... Show MoreThe effect of micro-and nano silica particles (silica SiO2 (100 μm), Fused silica (12nm)) on some mechanical properties of epoxy resin was investigated (Young's modulus, Flexural strength). The micro-and nano composites were prepared by using three steps process with different volume fraction of micro-and nano particles (1, 2, 3, 4, 5, 7, 10, 15, and 20 vol. %). Flexural strength and Young's modulus of nano composites were increased at low volume fraction (max. enhancement at 4 vol.% ). However at higher volume fraction both Young's modulus and flexural strength decrease. Moreover, above, the mechanical properties are enhanced more than that of neat epoxy resin. The flexural strength decreases with increasing the volume fraction of micr
... Show MoreThe high viscosity of heavy oil is a crucial factor that strongly affects its up-stream recovering, down-stream surface transporting and refining processes. Economical methods for recovering the heavy oil and reducing is very important and related to capital and/or operating cost. This research studies the treatment of Iraqi heavy crude oil, which characterize with high viscosity and low API which makes transportation of heavy crude oil a difficult mission, needs for treatment to reduce viscosity for facilitating transportation and processing. Iraqi heavy crude oil was used Sharqi Baghdad, which obtained from Baghdad east oil fields with API 22.2º.Many kinds of additives were used to reduce the viscosity, experiments were performed o
... Show MoreThat researchers in the play Science Find a theatrical form of an experimental creative, and these experiences taken from the innovation space aesthetic dialogue with the receiver, especially since with previous theatrical experience and is an extension of her, because the interactive theater theatrical terms that assume a pattern do from the depth of the relationship between supply playwright and the audience, which alters the receiving skills actually change, and to monitor these differing divided into three classes that include research, methodological framework (Chapter I) and includes, research problem, the importance of research and the need to him, the goal of the research, the limits Find it border, and the theoretical framework
... Show MoreIn this research, we studied the effect of concentration carriers on the efficiency of the N749-TiO2 heterogeneous solar cell based on quantum electron transfer theory using a donor-acceptor scenario. The photoelectric properties of the N749-TiO2 interfaces in dye sensitized solar cells DSSCs are calculated using the J-V curves. For the 〖(CH_3)〗_3 COH solvent, the N749-TiO2 heterogeneous solar cell shows that the concentration carrier together with the strength coupling are the main factors affecting the current density, fill factor and efficiency. The current density and current increase as the concentration increases and the strength coupling increases as the N749-TiO2 heterogeneous in solar cell. However, the efficiency is more sens
... Show MoreIn this experimental and numerical analysis, three varieties of under-reamed piles comprising one bulb were used. The location of the bulb changes from pile to pile, as it is found at the bottom, center, and top of the pile, respectively.