Background: one of the complications of power bleaching is surface roughness of enamel which increases the possibility of post bleaching teeth discoloration. The aim of the present study is to evaluate the effect of toothpaste containing nano hydroxyapatite, NovaMin and kin sense fluoride on surface roughness of human tooth enamel after laser bleaching with 35% hydrogen peroxide bleaching gel. Materials and Methods: Twenty human enamel incisors were cleaned and their labial surface polished up to #1200, then categorized into four equal groups; first group kept without bleaching as a control group, while the remaining three experimental groups were bleached with 35% hydrogen peroxide, and each group treated with a restore paste containing one of the following: nano hydroxyapatite, NovaMin, and Kin fluoride. Bleaching was done with laser hybrid system (DMC Whitening Lase II, Sao Paulo, Brazil). Enamel roughness values assessed by an atomic force microscopy (AA3000, Bosten, USA) before and after treatment with restore tooth paste. Results: Paired t-test used to compare the mean roughness values before and after treatment with each restore paste. One-way analysis of variance and Duncan post hoc tests used to determine the differences between mean roughness values of the groups. A p-value of 0.05 or less considered a significant. The results showed a highly significant statistical differences of remineralization of all types of restore tooth pastes. Conclusions: Nano hydroxyapatite past exhibiting a higher ability to reduce the surface roughness after laser bleaching than other tested pastes.
Zinc oxide (ZnO) nanostructures were synthesized through the hydrothermal method at various conditions growth times (6,7 and 8 hrs.) and a growth temperature (70, 90, and 100 ºC). The prepared ZnO nanostructure samples were described using scanning electron microscopy (SEM) and X-ray diffractometer to distinguish their surface morphologies and crystal structures. The ZnO samples were confirmed to have the same crystal type, with different densities and dimensions (diameter and length). The obtained ZnO nanostructures were used to manufacture gas sensors for NO2 gas detection. Sensing characteristics for the fabricated sensor to NO2 gas were examined at different operating temperatures (180, 200, 220, and 240) ºC with a low gas concentrati
... Show MoreThe researcher, in this academic research, seeks to highlight the role of the semantic production in the dramatic act and to know the extent of its work and importance, because drama is an act and the dramatic work is a group of acts. The dramatic meaning and act are two inseparable concepts that cannot be divided, because each dramatic act is a container of meanings through connotations, signs and symbols. The production of the connotations in the dramatic act is considered one of the important issues in the content language of communication between the sender and recipient in order to get to the intended meaning. These sign connotations engage the spectator in the codifying activity and get him immersed in the events. The research pres
... Show MoreThree scolopacids out of 150 are found infected with Haemoproteus scolopaci Galli-
Valerio 1929 and H. tringae n. sp. A detailed description of the new taxon is presented along
with a comparison of the diagnostic measurements between the two species.
The paper aims at making the Russian reader acquainted with the Iraqi Poet Badr Shakir as-Sayyab, and showing the effect of the village and the city in his soul, the theme which is reflected in his poetry. Therefore, the researcher has translated the verses pertaining to this topic from Arabic into Russian so as to make the Russian reader know the important phases that talk about the village and city. The researcher has concluded that the theme of place, village and city has occupied a good portion of As-Sayyab's poetry, and that he (the poet) hated the city and expressed his wrath against it, because he viewed the city as embodiment of money and the degeneration of man. As opposed to this, As-Sayyab he loved being a farmer, and was
... Show MoreScenes of love constitute a large space within the orbit of the movies, so that there is almost no film (no matter what kind) void of these scenes, as they are associated with many dimensions and they constitute a major attraction for viewers, and thus the direction solutions and their connection to the director's vision constitute a large part in the process of employing signs to highlight what should be highlighted or to refer to it symbolically on the grounds that the director does not have full freedom in the transfer of scenes of love at all levels as they are in reality. The research included three sections within the theoretical framework:The first section: the concept of image and its rhetorical importance. This section discussed
... Show MoreThis study seeks to uncover the aesthetics of the internal rhythm and its effectiveness in
enriching the poetic text with the music tone at represented in the art of repetition and the
permit and recycling division and put back on the chest and the naturalization interview and
counterpoint.
And try to stand on the impact of internal rhythm to highlight the meaning of spelling and
irony with poet Ibn Bassam Al-Bagdadi and have a close look at the literary and
psychological motivations that led the poet to employ these colors in his ridicule and the
extent of its contribution to intensify the poetic alphabetic flush.
And deepening the meanings and provide poetic text in different aesthetics, there is no doubt
tha
The recent escalation in Southeast Asia showed that the region is on the verge of political and economic crises through the United States and its allies imposing economic sanctions against China, and a military escalation that may begin with China’s invasion of Taiwan, especially since two-thirds of the American forces in the world are located in the Taiwan Strait and the South China Sea.
The United States claims that it is ready to defend the island of Taiwan in the event of the start of Chinese military operations, but the reality shows that the United States supports Taiwan militarily by equipping it with modern weapons to defend itself. Supporting Taiwan economically by engaging it in trade agreements with US allies in the r
... Show MoreAbstract The aim of this study is to identify the role played by the university in reinforcing the culture of voluntary work in college students and sequencing these roles according to their priority. To achieve this aim, the researcher used the descriptive approach. After being informed of the literature background and of the previous studies related to the core aim of this recent study, the researcher has built up a questionnaire of (20) items investigating the role of university in reinforcing the culture of voluntary work in the college students. The standardized features of the questionnaire have been checked for the purpose of the questionnaire validity (virtual and constructive validity) and stability (reconstruction and Cronbach's A
... Show More