Background This study aimed to develop remineralizing calcium-phosphate (CaP) etchant pastes for enamel conditioning before bracket bonding and evaluate the bonding performance, failure pattern, and enamel surface integrity post bracket debonding in comparison with the conventional phosphoric acid (PA) etchant gel. Material and Methods Micro-sized monocalcium phosphate monohydrate and hydroxyapatite (micro- and nano-sized) powders were mixed with various phosphoric and nitric acid concentrations to develop eight acidic CaP pastes. Ninety extracted human premolars were randomly assigned into eight experimental and one control group (n=10). The developed pastes and control (commercial 37% PA-gel) were applied onto the enamel using the etch-and-rinse protocol before bonding metal brackets. Shear bond strength and adhesive remnant index (ARI) scores were evaluated after 24 hours water storage (24 h) and post 5000 thermocycling (TC). Field emission scanning electron microscopy (FE-SEM) was used to evaluate enamel damage after bracket debonding. Results The developed CaP pastes, excepting MNA1 and MPA1, resulted in significantly lower SBS values and ARI scores than 37% PA gel. Etching with 37% PA yielded roughened, cracked enamel surfaces with excessive retention of adhesive residue. In contrast, enamel treatment with the experimental pastes exhibited smooth, unblemished surfaces, with obvious CaP re-precipitation induced by mHPA2 and nHPA2 pastes and to a lesser extent by MPA2 paste. Conclusions Three newly developed CaP etchant pastes (MPA2, mHPA2, and nHPA2) can be promising alternative enamel conditioners that outperform conventional PA by generating adequate bracket bond strengths besides precipitating CaP crystals on the enamel. Moreover, these pastes maintained unblemished enamel surfaces with no or minimal adhesive residue after bracket removal.
الوصف Mixed ligand complexes of Cu (II), Co (II) and Zn (II) with 2-((4-(1-(4-chlorophenylimino) ethyl) phenylimino) methyl) phenol (L) and histidine (His) have been prepared and diagnosed by ¹H and13 C NMR, FT-IR and electronic spectral data, thermal gravimetric, molar conductance and metal analysis measurements. The ligand (L) shows a bidentate nature and the coordination occurs through N and O atoms of imine group and phenol group respectively whereas (His) behave as tridentate ligand, coordinating through the-NH2 group and carboxylate oxygen group and N atoms of imidazole ring. The analytical studies for three complexes have shown octahedral structure. The anticancer activity was screened against human cancer cell such Follicular
... Show MoreThe current study aimed at (identifying the impact of a proposed strategy based on the realistic mathematics theory in the mathematical interrelation among the third intermediate grade students), two samples from the third intermediate grade were tested in a school affiliated to Rusafa I General education Directorate in Baghdad for the academic year (2022-2021)the experimental group will study according to the proposed strategy and it consisted of (30) female students , the control group will study through the traditional method and the number of its students is (30), thus the study sample consisted of (60) female students, the two groups were equalized in the variables (age in months, intelligence, prior knowledge) and to achieve the study
... Show MoreThe objective Effect of Internal and External Environment and its Psychological & Practical Reflection on the Political Decision-Making Process
Background: Salivary tumors are uncommon, being of low incidence worldwide. This study aimed to assess cases collected in this series of salivary gland tumors in regard to histopathological typing, in relation to age, site and gender. Materials and methods: This is a retrospective study; cases were collected from public and private laboratories. A total number of 171 cases were collected. The slides were reviewed and reclassified for histopathological typing according to WHO classification 2005. Results: Benign tumors were more common than malignant tumors. The most common histological type was benign mixed tumor, followed by Warthin’s tumor. The most common malignant tumor was adenoid cystic carcinoma. One hundred twenty three cases ou
... Show MoreThis paper tackles in detail the functional shift of parts of speech, such as the shift of a verbal clause to an adjectival clause, along with the types of such a shift. The researcher identified the important features of participles, as well as the concept of participles, adjectives, and their types. Also, the most important changes that affect the participles during such shifts. Further, an exposition is made of the different producers through which a verbal clause is changed into an adjectival one in Russian.
This type of functional shift in parts of speech is seen as a process of deriving most of the new words in contemporary Russian. Russian is very rich in new words, whether by way of processe
... Show MoreA simple physical technique was used in this study to create stable and cost-effective copper oxide (CuO) nanoparticles from pure copper metal using the pulsed laser ablation technique. The synthesis of crystalline CuO nanoparticles was confirmed by various analytical techniques such as particle concentration measurement using atomic absorption spectrometry (AAS), field emission scanning electron microscopy (FE-SEM), the energy dispersive X-ray (EDX), and X-ray diffraction (XRD) to determine the crystal size and identify of the crystal structure of the prepared particles. The main characteristic diffraction peaks of the three samples were consistent. The corresponding 2θ is also consistent, and the cytotoxicity of the nanoparticles was
... Show MoreComposite materials are widely used in the engineered assets as aerospace structures, marine and air navigation owing to their high strength/weight ratios. Detection and identification of damage in the composite structures are considered as an important part of monitoring and repairing of structural systems during the service to avoid instantaneous failure. Effective cost and reliability are essential during the process of detecting. The Lamb wave method is an effective and sensitive technique to tiny damage and can be applied for structural health monitoring using low energy sensors; it can provide good information about the condition of the structure during its operation by analyzing the propagation of the wave in the
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