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Context: Radiographs have an essential role in Chronological Age (CA) estimation and are being used for dental age (DA) determination. Aims: Detecting the validity of Nolla's method (NM) for the age assessment of Kurdish Iraqi children (KIC). Methods and Material: A retrospective study was performed using orthopantomographs (OPGs) of 354 subjects aged from 4 to 13 years (178 boys and 176 girls) and their recording files. Subjects were divided into nine study groups: 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 years old. The chronological age (CA) was subtracted from the DA to find the validity of NM; the positive results indicated the overestimation of age, whereas the negative results indicated for underestimation. The data were recorded through a digitalised system using Microsoft Excel worksheet and analysed by Statistical Package for the Social Sciences (SPSS, version 25) programme using the dependent T-test and graphical analysis. The level of P value used in this study was set at < 0.05. Results: The DA is underestimated in ages 9 to 13 in boys and girls. The highest difference in DA--CA was at the age of 9 years (-0.146 ± 0.162). Conclusions: NM for age estimation was slightly overestimated in age groups of 4, 5, 6, 7, and 8 years in boys and girls without statistically significant differences. However, this method underestimated the ages of KIC ranging from 9 to 13 years significantly. [ABSTRACT FROM AUTHOR]

Co-based alloy cladding layers (wallex50 and wallex55) were synthesised on 316L stainless steel by vacuum cladding. Experimental results showed that wallex50 composed of γ-Co, WC, Co6W6C, Cr7C3, in whichin situreinforcement WC phases were homogeneously distributed in the layer, having a clear and stable interface structure. Wallex55 with externally added WC particles was composed of γ-Co, WC, Co6W6C, Cr7C3, CrB, CoWB. The average microhardness of wallex50 and wallex55 was 794 ± 29 and 939 ± 24 HV, respectively. Nevertheless, wallex50 showed a better resistance to friction and wear than wallex55, which was not in a cross line with Archard’s law. Relative wear resistance of wallex50 was 23.36, which was 1.56 times greater than that of wallex55. The improvement of friction and wear for wallex50 could be due to the fact that thein situsynthesised WC particles increased the friction and wear resistance by the pinning effect of the retained reinforced phase on the Co-based matrix. [ABSTRACT FROM AUTHOR]

Fe-based coatings with high V and Cr content were obtained by laser cladding using Fe-based powder with different Cr3C2 and FeV50 content. The results showed that Fe-based coatings were uniform and dense. The constituent phases were mainly composed of α-Fe solid solution with the increase of Cr3C2 and FeV50, γ-Fe and V8C7 phases were achieved. The microstructure of the coatings exhibited a typical dendrite structure. The concentration of C, V and Cr were saturated in dendritic areas, and the other alloying elements were mainly dissolved in the interdendritic areas. The hardness and wear resistance of Fe-based coatings were enhanced with the Cr3C2 and FeV50 addition. The specimen with 15% Cr3C2 and 16% FeV50 had the highest hardness of 66.1 ± 0.6 HRC, which was 1.05 times higher than the sample with 4.5% Cr3C2 and 5% FeV50, and the wear resistance of the former was three times greater than the latter. [ABSTRACT FROM AUTHOR]

Objective: To review the current knowledge of CAD/CAM in dentistry and its development in the mentioned field. Sources: An electronic search was conducted across Ovid Medline, complemented by manual search across individual databases, such as Cochrane, Medline and ISI Web of Science databases and Google Scholar for literature analysis on the mentioned topic. The studies were reviewed thoroughly. This paper summarizes the current scientific and clinical opinions through a brief overview regarding the preferred way of utilizing CAD/CAM in dentistry. Conclusions: The importance of CAD/CAM systems has seen a dramatic development in the number of products and procedures over last decades, with a concomitant rise in publications on the topic. Literature suggests that using this technology permits carrying out dental treatments feasibly particularly for fixed dental appliances. Based on the previous findings, it is concluded that in office CAD/CAM technique appears to be the most common technique currently available, which is rapid, easy and keeps time. CAD/CAM systems are variable; therefore, using the right system with a logical approach for treating patients are quite mandatory. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effects of two surface-coating methods on the shear bond strength (SBS) of veneering ceramics (VC) to zirconia. Eighty pre-sintered zirconia cubes were randomly assigned into four study groups: E60S, E60P, N60S, and N60P. The zirconia surface was coated with a mixture of two types of glaze and alumina (<60 μm) by airbrush spraying and fine- brush painting. Surface roughness (Ra), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and SBS measurements (both initial and artificial aged conditions, including one month of water storage) were performed. The Ra results revealed significant differences among all groups (p < 0.001). The N60P group exhibited higher values of Ra (5.717 ± 0.20 µm) and SBS before and after water storage with values of 37.22 ± 4.954 MPa and 34.42 ± 3.977 MPa, respectively. The fine-brush coatings showed significantly higher SBS than that of airbrush coatings, in both initial and artificial conditions. Both coating methods and various coating materials (p < 0.001) produced a significant influence on VC-zirconia SBS. A significant correlation between Ra and SBS (Spearman's rho = 0.808; p < 0.001) was found. The novel coating by fine-brush painting is a promising surface treatment and an easy technique for obtaining a rougher surface, which subsequently improves the bond strength to VC. [ABSTRACT FROM AUTHOR]