Monomers Release from Direct and Indirect Resin-Based Restorations after Immersion in Common Beverages.

Impurities or degradation of the components of resin-based materials have been throughout investigated by the dental scientific community. The aim of this study is to examine if there is a release of monomers from resin-based materials when they are immersed in common beverage materials which are consumed by the population in large quantities. Three representative dental materials were used for this study, one resin composite indicated for direct restorations and two Computer Aided Design and Computer Aided Manufacturing (CAD/CAM) materials with different methods of fabrication. Forty specimens were fabricated from each material using a low-speed precision sectioning blade 12 × 14 × 2 mm in size and immersed in wine, coffee or cola for 48 h and 12 days, equivalent to 1 month and 1 year of consumption. The materials released more monomers when the materials were immersed in the wine solution (p < 0.05). CAD/CAM materials release less monomers compared to the resin composite material indicated for direct restorations (p < 0.05). The CAD/CAM materials leach a limited quantity of monomers when they are immersed in common beverages due to the manufacturing process which includes high-temperature/high-pressure polymerization.

Analytical Methods for Nanomaterial Determination in Biological Matrices.

Nanomaterials are materials in which at least one of the three dimensions ranges from 1 to 100 nm, according to the International Organization for Standardization (ISO). Nanomaterials can be categorized according to various parameters, such as their source, their shape, and their origin. Their increasing use in industrial settings, everyday items, electronic devices, etc. poses an environmental and biological risk that needs to be assessed and appropriately addressed. The development of reliable analytical methods for both characterization and quantification of nanomaterials in various matrices is essential. This review summarized the recent trends in analytical methodologies for the characterization and determination of nanoparticles in biological matrices.

Female gender is independently associated with increased carotid temperatures in patients with coronary artery disease.

BACKGROUND: Limited are the data regarding the sex differences in functional carotid artery characteristics. Microwave Radiometry (MWR) is a new noninvasive method, which measures in vivo instantly the internal temperatures of tissues, reflecting inflammation. The aim of the present study was to investigate whether in patients with coronary artery disease (CAD), gender related differences apply in carotid plaque functional characteristics, as assessed by MWR. METHODS: Consecutive patients with significant CAD were included in the study. All patients underwent evaluation of both carotid arteries by 1) ultrasound and 2) MWR. During ultrasound common carotid IMT and plaque thickness were assessed according to Mannheim consensus. During MWR measurements, temperature difference (ΔT) was assigned as maximal temperature along the carotid artery minus minimum. ΔT ≥0.90°C was assigned as high ΔT. RESULTS: In total 364 patients with significant CAD were included in the study. Of these 54 were female and 310 were male. Max plaque thickness and ccIMT were similar between males and females (2.38±1.16 vs. 2.46±1.12mm, p=0.63 and 0.944±0.172 vs. 0.942±0.169mm, p=0.96). Carotid arteries of females showed higher ΔT values (1.16±0.48 vs 0.87±0.45°C, p<0.001). Interestingly, females had more commonly high ΔT values bilaterally (35.2% vs 15.5%, p=0.001). In multivariate analysis, female sex was independently associated with bilateral high ΔT, when adjusted to potential covariates (OR=2.78, 95% CI=1.42-5.45, p=0.003). CONCLUSIONS: In patients with CAD, sex specific differences apply in functional but not in structural carotid artery characteristics. Whether this discrepancy has prognostic significance, remains to be clarified in future studies.

Bilateral symmetry of local inflammatory activation in human carotid atherosclerotic plaques.

INTRODUCTION: Only a few studies have investigated the structural and functional characteristics of carotid arteries bilaterally. Furthermore, there is controversy as to whether inflammation in paired vascular beds is a local or systemic phenomenon. We aimed to examine, in patients with coronary artery disease, whether intra-subject left and right carotid arteries have similar inflammatory status, as determined non-invasively by microwave radiometry (MWR). METHODS: Consecutive patients (n=200) with significant coronary artery disease were evaluated via an ultrasound echo-colour Doppler (US-ECD) study of both carotid arteries and temperature measurements with MWR. During thermography, thermal heterogeneity (ΔT) was defined as the maximum temperature along the carotid artery minus the minimum temperature. RESULTS: Mean T was similar between the left and right carotid arteries (0.78 ± 0.48 vs. 0.84 ± 0.52°C, p=0.12). Mean right intima-media thickness (IMT) was greater compared to mean left IMT (2.16 ± 1.20 vs. 1.93 ± 0.94 mm, p<0.01). In all carotids, there was a correlation between left and right carotid plaque ΔT (R=0.38, p<0.001) and between left and right IMT (R=0.48, p<0.001). Independent predictors for the presence of bilateral carotid plaques were found to be the extent of coronary artery disease, high ΔT, and therapy with angiotensin II receptor blockers; predictors for the presence of high ΔT bilaterally were bilateral carotid plaques, male sex, diabetes mellitus, and hypertension. CONCLUSIONS: There is bilateral inflammatory activation in the carotid atherosclerotic lesions of patients with coronary artery disease. At this stage of carotid disease, arterial hypertension and diabetes mellitus are more strongly correlated with bilateral functional abnormalities in carotid plaques than with structural changes.

Morphological and functional assessment of carotid plaques have similar predictive accuracy for coronary artery disease.

BACKGROUND AND PURPOSE: Microwave radiometry allows noninvasive in vivo measuring of internal temperature of tissues reflecting inflammation. In the present study, we evaluated the predictive accuracy of this method for the diagnosis of coronary artery disease (CAD). METHODS: Consecutive patients (n=287) scheduled for coronary angiography were included in the study. In carotid arteries of both groups, the following measurements were performed: (1) intima-media thickness (IMTmax) and (2) temperature measurements by microwave radiometry (ΔTmax). C-statistic and net reclassification improvement were used to compare the prediction ability of the markers IMTmax and ΔTmax for the presence of CAD and multivessel CAD. RESULTS: Of 287 patients, 239 had stenoses ≥50% (CAD group), and 48 did not have significant stenoses (NO-CAD group). ΔTmax was an independent predictor for the presence of CAD and multivessel CAD, showing similar predictive accuracy to intima-media thickness, as assessed by c-statistic and net reclassification improvement. CONCLUSIONS: Local inflammatory activation, as detected by microwave radiometry, has similar predictive accuracy to intima-media thickness for the presence and extent of CAD.

In vivo measurement of plaque neovascularisation and thermal heterogeneity in intermediate lesions of human carotid arteries.

OBJECTIVES: Both neoangiogenesis and inflammation contribute in atherosclerosis progression. Contrast-enhanced ultrasound (CEUS) provides visualisation of plaque neovascularisation. Microwave radiometry (MR) allows in vivo non-invasive measurement of temperature of tissues, reflecting inflammatory activation. We assessed the association of carotid plaque temperature, measured by MR, with plaque neovascularisation assessed by CEUS in intermediate lesions. METHODS: Consecutive patients with coronary artery disease and carotid atherosclerosis underwent carotid ultrasound imaging, CEUS and MR. Plaque texture, plaque surface and plaque echogenicity were analysed. Contrast enhancement (CE) by CEUS was defined as the % percentage of signal intensity difference, prior and post contrast infusion. Thermal heterogeneity (ΔT) was assigned as maximal temperature along the carotid artery minus minimum. RESULTS: Eighty-six carotid arteries of 48 patients were included. Fatty plaques had higher CE% and ΔT compared with mixed and calcified (p<0.01 for all comparisons). Heterogeneous plaques had higher CE% and ΔT compared with homogenous (p<0.01 for all comparisons). Plaques with irregular surface had higher CE% and ΔT compared with plaques with regular (p<0.01 for all comparisons). There was a good correlation between ΔT and CE (R=0.60, p<0.001). CONCLUSIONS: Carotid plaque neovascularisation on CEUS examination is associated with increased thermal heterogeneity and ultrasound characteristics of plaque vulnerability in intermediate lesions.

Matrix metalloproteinases and vulnerable atheromatous plaque.

Atherosclerotic coronary artery disease, the underlying basis for ischemic heart disease, is the leading cause of death and disability in the USA and recent trends indicate that coronary artery disease is also becoming a major public health problem in developing countries [1]. Atherosclerosis is a continuous process that is initiated early in life, which gradually progresses with potentially devastating consequences: atherosclerotic plaque rupture is the most common underlying pathological mechanism creating acute ischemic coronary syndromes [2]. This term refers to the process of disruption of the endothelial surface and the exposure of the underlying prothrombotic vessel wall to circulating platelets and coagulation factors. In order to identify the high-risk plaque we need to recognize its specific morphological and functional characteristics. The morphological characteristics have been identified in several human histopathological and in vivo studies, and include: 1) a large lipid core (≥40% plaque volume) composed of free cholesterol crystals, cholesterol esters, and oxidized lipids impregnated with tissue factor, 2) a thin fibrous cap depleted of smooth muscle cells and collagen, 3) an outward (positive) remodeling, 4) inflammatory cell infiltration of fibrous cap and adventitia (mostly monocyte- macrophages, activated T cells and mast cells), and 5) increased neovascularization. The terms vulnerable, unstable or 'high-risk' are now widely used to describe plaques that exhibit such features, irrespective of whether rupture of the fibrous cap is present [3].

Microwave radiometry: a new non-invasive method for the detection of vulnerable plaque.

Atherosclerosis and its consequences are the most rapidly growing vascular pathology, with myocardial infarction and ischemic cerebrovascular accident to remain a major cause of premature morbidity and death. In order to detect the morphological and functional characteristics of the vulnerable plaques, new imaging modalities have been developed. Intravascular thermography (IVT) is an invasive method, which provides information on the identification of the high-risk atheromatic plaques in coronary arteries. However, the invasive character of IVT excludes the method from primary prevention. Microwave radiometry (MR) is a new non-invasive method, which detects with high accuracy relative changes of temperature in human tissues whereas this thermal heterogeneity is indicative of inflammatory atherosclerotic plaque. Both experimental and clinical studies have proved the effectiveness of MR in detecting vulnerable plaque whereas recent studies have also revealed its association with plaque neoangiogenesis as assessed by contrast enhanced carotid ultrasound (CEUS).