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This paper presents the influence of freeze–thaw cycles on physical and mechanical properties of Alvand granitoids hard rocks, in the west of Iran. For this purpose, three different types of Alvand granitoid rocks were selected and studied. For assessment of freeze–thaw weathering effects, a long-term freeze–thaw test was carried out for 300 cycles. P-wave velocity, porosity, water absorption, dry density, uniaxial compressive strength, and tensile strength of specimens were determined prior to doing the test and after every 50 cycles. The results of this study show that, by increases in the number of freeze–thaw cycles, uniaxial compressive strength, tensile strength, dry density, and P-wave velocity decreases, whereas the water absorption and porosity increases. P-wave velocity and tensile strength were also suggested as the best indicators to assess the effects of freeze–thaw cycles on the physical and mechanical properties of the studied granites.

Hot compression tests were carried out on the duplex α + β leaded brass CuZn39Pb3 in temperature range of 600–800 °C and at strain rates of 0.001–1 s−1. A self-consistent model was used to analyze the flow behavior of the constituents and the material. A linear viscoplastic model was used to relate the flow stress of β and α + β composite to strain rate and the corresponding viscosity parameters were calculated at various deformation conditions. Using the viscosity parameters of β and α + β and the volume fractions of the constituents, the viscosity parameter of α was calculated. The values of the viscosity-like parameters and strain rate sensitivity for β and α + β composite were calculated using the nonlinear powerlaw viscoplastic equation. The results showed that the flow stress of α calculated using the self-consistent model was considerably higher than that of β. The difference could be attributed to the lower Zn content in α. The flow stress of α + β composite was calculated using the law of mixture rule. The law of mixture modeling of α + β composite for the iso-strain condition resulted to the overestimation of flow stress. The difference between the experimental and predicted results was attribute to the strain partitioning between α and β.

In this paper, the effects of weathering on durability and deformability properties for three different types of granitoid rocks were investigated. Five weathering grades ranging from fresh to completely weathered rocks were considered for each rock type. Deformability has been evaluated based on failure strain, tangent and secant modulus. For measuring these parameters, at least five uniaxial compressive strength tests with axial strain recorded were conducted on each weathering grade. To assess the weathering effect on the durability behavior of these rocks, a slake durability test was performed up to 40 cycles. The obtained results indicated that uniaxial compressive strength and elastic modulus dramatically decrease with increasing weathering grade. After moderately weathering grade, remarkable damage was observed in the structure and fabric of considered rocks. The results from slake durability tests showed that the slake durability index for each weathering grade has a certain changes trend which can be used in determination of the weathering grade and the long-term durability assessment. Moreover, the results showed that for evaluation of the long-term durability of the mentioned rock types, at least eight cycles should be considered, while two cycles were sufficient for estimation of weathering grade.

The aim was to investigate the ability of self-assembling Peptide P11-4 Matrix (SAPM) to remineralize artificial initial caries lesions compared to the use of fluoride varnish. Volunteers were recruited for this randomised, cross-over in situ trial. Bovine specimens, half including orthodontic brackets, were recessed on the buccal aspects of mandibular appliances. Specimens included internal sound enamel control, a demineralised control and a part exposed during the in situ phase. Each phase lasted four weeks, followed by a one-week washout. Treatment groups were: A: negative control, no treatment,B: positive control, 22,600 ppm fluoride varnish,C: test group, 1,000 ppm SAPM. Laser fluorescence values (LF) were measured before/after demineralisation, and after the in situ period. Micro-CT analysis was used to assess mineral changes within the specimens after the in situ phase. In specimens without brackets, ΔLF values after in situ phase were: A: +5.28, B: +0.85, C: −2.89. Corresponding ΔLF for specimens with brackets were: A: +5.77, B: +1.30, C: −3.15. LF-values between groups significantly differed from each other (p < 0.0001) after the in situ phase. Micro-CT analysis yielded no significant difference among groups for specimens without brackets. For specimens with brackets, the test group showed significantly more remineralisation than the negative (p = 0.01) and positive control (p = 0.003). Within the limitations of the study, SAPM showed prevention of caries and remineralisation of enamel around orthodontic brackets.

Enamel demineralisation can develop on smooth surfaces as an undesirable side effect during orthodontic treatment with fixed appliances. This study aimed to evaluate the ability of 38% silver diamine fluoride in remineralisation (as estimated by fluorescence gain) of artificial initial lesions in smooth surfaces of human enamel. The smooth surfaces of 50 human tooth samples were artificially demineralised and 45 samples were allocated randomly into three groups receiving a single treatment with a varnish: group I: Riva Star (silver diamine fluoride, SDF), group II: Bifluorid 12 (NaF, CaF 2 ), and group III: Cervitec F (CHX, CPC, NH 4 F). Five samples were assigned as a negative control group without treatment. All samples were exposed to pH-cycling for 28 days. Fluorescence behavior was measured using Quantitative light-induced fluorescence before and after demineralisation and up to four weeks on a weekly basis. Analysis of variance (ANOVA) with Tukey–Kramer post-hoc tests and repeated measures ANOVA were used for statistical evaluation (α = 0.05). After demineralisation, all samples showed mean ΔF of − 16.22% ± 4.35, without significance differences between the fluorescence behaviour of the samples ( p  = 0.251). After 28 days group comparison showed a statistically significant difference ( p  = 0.034) for ΔF values: the lowest fluorescence values were found in group I (SDF, mean ΔF − 16.47 ± 6.08) with a significant difference compared to group III (Cervitec F, mean ΔF − 11.71 ± 4.83). In group II (Bifluorid 12) mean ΔF value was − 15.55 ± 2.15) without statistically significant differences to groups I and III. The fluorescence behaviour of SDF varnish on smooth surfaces with artificial initial enamel lesions was significantly lower compared to Cervitec F varnish after short time use.

The Alvand batholith is one of the largest plutonic bodies in the west of Iran. In this research, several physico-mechanical tests have been performed on granodiorite and porphiroid monzogranite consisting of five degrees of weathering in Hamedan area, west of Iran. Furthermore, weathering process of Alvand granitoid is studied by chemical analysis and petrographical studies. The results indicated that engineering properties of weathered granodiorite and monzogranite vary over the wide range depending on the degree of weathering. On the other hand, this research is focused on the assessment of relationship between weathering indices and uniaxial compressive strength. For this reason, some of the most important weathering indices are reviewed. It should be noted that, application of these chemical, engineering and petrographical indices are good quantitative indicators for describing the degree of weathering. Using these indices for the assessment of uniaxial compressive strength of granodiorite and monzogranite rocks, yields suitable and meaningful results.

Hot deformation characteristics of 2205 duplex stainless steel were analyzed by performing hot compression tests at a temperature range of 950–1200 °C and a strain rate of 0.001–1 s −1 . Flow stress was modeled by the constitutive equation of hyperbolic sine function. The constants of n , A , α, and the apparent activation energy were determined at different strains. They were then fitted by polynomial equations. Using the hyperbolic sine function and the relations derived between constants and strain flow curves were successfully modeled. Microstructural evolutions were characterized using optical microscopy and electron back scattered diffraction techniques. The results showed that dynamic recovery in ferrite is accelerated at higher temperatures followed by transformation to continuous dynamic recrystallization. Dynamic recrystallization in austenite was postponed by the accommodation of strain in ferrite and very few internal boundaries in austenite. At high strain rates, dynamic recovery in ferrite and dynamic recrystallization in austenite are very slow. Consequently, the total recrystallized fraction decreases. At low temperatures this situation may cause flow instabilities. At low strain rates, softening processes dominate in austenite and ferrite whereas at intermediate strain rates, the formation of substructures is observed in both phases.

ObjectivesFor an ORCA/EFCD consensus, this systematic review assessed the question “How to intervene in the caries process in proximal caries in adolescents and adults”.Material and methodsSeparating between the management of initial and cavitated proximal caries lesions, Medline via PubMed was searched regarding non-operative/non-invasive, minimally/micro-invasive and restorative treatment. First priority was systematic reviews or randomized controlled trials (RCTs), otherwise cohort studies. After extraction of data, the potential risk of bias was estimated depending on the study type, and the emerging evidence for conclusions was graded.ResultsRegarding non-invasive/non-operative care (NOC), no systematic reviews or RCTs were found. In cohort studies (n = 12) with a low level of evidence, NOC like biofilm management and fluoride was associated with a low proportion and slow speed of progression of initial proximal lesions. Minimally/micro-invasive (MI) treatments such as proximal sealants or resin infiltration (four systematic reviews/meta-analyses) were effective compared with a non-invasive/placebo control at a moderate level of evidence. Data on restorative treatment came with low evidence (5 systematic reviews, 13 RCTs); with the limitation of no direct comparative studies, sample size-weighted mean annual failure rates of class II restorations varied between 1.2 (bulk-fill composite) and 3.8% (ceramic). Based on one RCT, class II composite restorations may show a higher risk of failure compared with amalgam.ConclusionsProximal caries lesions can be managed successfully with non-operative, micro-invasive and restorative treatment according to lesion stage and caries activity.Clinical relevanceProximal caries treatment options like non-operative, micro-invasive and restorative care should be considered individually.

Aim: The aim of this study was to assess inter- and intra-examiner reproducibility and accuracy in the detection and assessment of occlusal caries in extracted human teeth using a newly developed visual method for caries diagnosis (International Caries Detection and Assessment System, ICDAS-II). Serial sectioning and microscopy were used as the ‘gold standard’. Methods: The occlusal surfaces of 100 teeth were examined by 4 dentists using the ICDAS-II graded scores 0–6. Thereafter the teeth were serially sectioned and assessed for depth of the lesion with two histological classification systems. Results: The weighted kappa values for inter- and intra-examiner reproducibility for the ICDAS-II examination were 0.62–0.83. There was a moderate relationship between the visual and both histological examinations (r s = 0.43–0.72). At the D1 diagnostic threshold (enamel and dentine lesions) specificity was 0.74–0.91 and sensitivity was 0.59–0.73. At the D3 diagnostic threshold (dentine lesions) specificity was 0.82–0.94 and sensitivity was 0.48–0.83 for the 4 examiners. Conclusion: The ICDAS-II system has demonstrated reproducibility and diagnostic accuracy for the detection of occlusal caries at varying stages of the disease process which are comparable to previously reported data using similar visual classification systems.

Hot deformation characteristics of 2304 duplex stainless steel were analyzed by hot compression tests at temperature range of 850–1150 °C and strain rates of 0.001–1 s−1. The flow curves at low temperatures and high strain rates were suggesting sluggish dynamic recovery (DRV) in ferrite and partial dynamic recrystallization (DRX) in austenite. However, at high temperatures and low strain rates, the flow curves showed implied the domination of DRV in ferrite. The hyperbolic sine equation with activation energy of 508 kJ/mol could relate the processing parameters. Microstructural observations showed that DRV in ferrite is the controlling mechanism at all deformation conditions. However, at high temperatures and strain rates partial DRX could also occur in austenite. Based on the law of mixture and Baragar’s equations a modified model was proposed to consider work hardening and dynamic softening in the constituents. The model could satisfactorily predict the flow curves at different deformation regimes.