Effect of different finishing and polishing procedures on surface roughness and microbial adhesion on highly-filled composites for injectable mold technique.

OBJECTIVE: To evaluate the effect of different finishing and polishing procedures on surface roughness and microbial adhesion and viability of Streptococcus mutans on novel highly-filled composites for injectable mold technique. MATERIALS AND METHODS: One hundred sixty specimens were divided into four material groups: FSF (Filtek Supreme Flowable Restorative), TE (Tetric EvoFlow), GUI (G-aenial Universal Injectable) and GUF (G-aenial Universal Flo). Within each group, specimens were split regarding finishing and polishing (F/P) procedures into: SLD (Sof-Lex Discs), SLS (Sof-Lex Spirals), OG (OneGloss) and PG (PoGo). Surface roughness was analyzed using profilometer (Ra and Rz) and scanning electron microscopy (SEM) and Strep. mutans biofilm formation was analyzed using colony forming unit (CFU) and cell viability assay. Two-way analysis of variance (ANOVA) followed by Tukey's post hoc test were used for comparison among groups, Pearson's coefficient was applied for the correlation between Ra and CFU/ml and all data were presented as mean ± SD. RESULTS: Both materials and F/P procedures affect Ra, Rz and Strep. mutans CFU/ml values (p ≤ 0.05). Considering the Ra and Rz, GUI and GUF revealed lower values, compared to FSF and TE and SLD and SLS revealed lower values, compared to OG and PG. Considering the Strep. mutans CFU/ml and viability, GUI and TE presented lower values, compared to GUF and FSF and SLD and SLS presented lower values, compared to OG and PG. Moderate positive correlation was found between Ra and CFU/ml (r = 0.552). CONCLUSIONS: The smoothest surfaces possess GUI and GUF, among materials and SLD and SLS, among F/P procedures. GUI adhered the lowest amount of Strep. mutans, due to the smoothest surfaces. FSF and GUF revealed the highest amount of Strep. mutans, due to bis-GMA, bis-MEPP and TEGDMA in their composition. CLINICAL SIGNIFICANCE: The findings of the present study may be beneficial for the proper selection of highly-filled composites and an adequate finishing and polishing procedure when performing the injectable mold composite resin veneer technique.

Oxidized low-density lipoprotein as a biomarker of cardiovascular diseases.

Atherosclerosis is a life-long illness that begins with risk factors, which in turn contribute to the development of subclinical disease, followed by the establishment of overt cardiovascular disease (CVD). Thrombotic-occlusive complications of atherosclerosis are among the most widespread and costly health problems. Oxidized low-density lipoprotein (OxLDL) plays an important role in atherogenesis by promoting an inflammatory environment and lipid deposition in the arterial wall. As cardiovascular events occur in individuals without common risk factors, there is a need for additional tools that may help in CVD risk assessment and management. The use of biomarkers has improved diagnostic, therapeutic and prognostic outcome in cardiovascular medicine. This review elaborates on the value of circulating OxLDL as a biomarker of CVD. Three enzyme-linked immunosorbent assays (4E6, DLH3 and E06) using murine monoclonal antibodies for determination of OxLDL blood levels have been developed. However, none of these assays are currently approved for routine clinical practice. We identified studies investigating OxLDL in CVD (measured by 4E6, DLH3 or E06 assay) by searching the PubMed database. Circulating OxLDL was found to be associated with all stages of atherosclerosis, from early atherogenesis to hypertension, coronary and peripheral arterial disease, acute coronary syndromes and ischemic cerebral infarction. The results of studies investigating the usefulness of OxLDL for CVD prediction were also summarized. Furthermore, OxLDL was found to be associated with pathologic conditions linked to CVD, including diabetes mellitus, obesity and metabolic syndrome (MetS). In addition, we have addressed the mechanisms by which OxLDL promotes atherogenesis, and the effects of antiatherogenic treatments on circulating OxLDL. Finally, we highlight the evidence suggesting that lipoprotein (a) [Lp(a)] is the preferential carrier of oxidized phospholipids (OxPL) in human plasma. A strong association between OxPL/apoB level (representing the content of OxPL on apolipoprotein B-100 particles, measured by E06 assay) and Lp(a) has been determined.

Thrombin stimulates VSMC proliferation through an EGFR-dependent pathway: involvement of MMP-2.

In this study, the role of epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK1/2), heparin-binding EGF-like growth factor (HB-EGF), general metalloproteinases, matrix metalloproteinases-2 (MMP-2) in mediating the mitogenic action of thrombin in rat vascular smooth muscle cells (VSMC) was investigated. The incubation of rat VSMC with thrombin (1 U/ml) for 5 min resulted in significant (p < 0.001) increase of ERK1/2 phosphorylation by 8.7 ± 0.9-fold, EGFR phosphorylation by 8.5 ± 1.3-fold (p < 0.001) and DNA synthesis by 3.6 ± 0.4-fold (p < 0.001). Separate 30-min pretreatments with EGFR tyrosine kinase irreversible inhibitor, 10 µM PD169540 (PD), and 20 µM anti-HB-EGF antibody significantly reduced thrombin-stimulated EGFR and ERK1/2 phosphorylation by 81, 72 % and by 48 and 61 %, respectively. Furthermore, the same pretreatments with PD or anti-HB-EGF antibody reduced thrombin-induced VSMC proliferation by 44 and 45 %, respectively. In addition, 30-min pretreatments with 10 µM specific MMP-2 inhibitor significantly reduced thrombin-stimulated phosphorylation of both EGFR and ERK1/2 by 25 %. Moreover, the same pretreatment with MMP-2 inhibitor reduced thrombin-induced VSMC proliferation by 45 %. These results show that the thrombin-induced DNA synthesis correlates with the level of ERK1/2 activation rather than EGFR activation. These results further suggest that thrombin acts through EGFR and ERK 1/2 signaling pathways involving MMP-2 to upregulate proliferation of VSMC.

Hyperbaric Oxygen Therapy and Vascular Complications in Diabetes Mellitus.

Vascular complications in patients with diabetes mellitus (DM) are common. Since impaired oxygen balance in plasma plays an important role in the pathogenesis of chronic DM-associated complications, the administration of hyperbaric oxygen therapy (HBOT) has been recommended to influence development of vascular complications. Hyperbaric oxygen therapy involves inhalation of 100% oxygen under elevated pressure from 1.6 to 2.8 absolute atmospheres in hyperbaric chambers. Hyperbaric oxygen therapy increases plasma oxygen solubility, contributing to better oxygen diffusion to distant tissues and preservation of the viability of tissues reversibly damaged by atherosclerosis-induced ischemia, along with microcirculation restoration. Hyperbaric oxygen therapy exerts antiatherogenic, antioxidant, and cardioprotective effects by altering the level and composition of plasma fatty acids and also by promoting signal transduction through membranes, which are impaired by hyperglycemia and hypoxia. In addition, HBOT affects molecules involved in the regulation of nitric oxide synthesis and in that way exerts anti-inflammatory and angiogenic effects in patients with DM. In this review, we explore the recent literature related to the effects of HBOT on DM-related vascular complications.

Effects of IGF-1 on the Cardiovascular System.

Cardiovascular (CV) diseases are the most common health problems worldwide, with a permanent increase in incidence. Growing evidence underlines that insulin-like growth factor 1 (IGF-1) is a very important hormone responsible for normal CV system physiology. IGF-1 is an anabolic growth hormone, responsible for cell growth, differentiation, proliferation, and survival. Despite systemic effects, IGF-1 exerts a wide array of influences in the CV system affecting metabolic homeostasis, vasorelaxation, cardiac contractility and hypertrophy, autophagy, apoptosis, and antioxidative processes. The vasodilatory effect of IGF-1, is achieved through the regulation of the activity of endothelial nitric oxide synthase (eNOS) and, at least partly, through enhancing inducible NOS (iNOS) activity. Also, IGF-1 stimulates vascular relaxation through regulation of sodium/potassiumadenosine- triphosphatase. Numerous animal studies provided evidence of diverse influences of IGF-1 in the CV system such as vasorelaxation, anti-apoptotic and prosurvival effects. Human studies indicate that low serum levels of free or total IGF-1 contribute to an increased risk of CV and cerebrovascular disease. Large human trials aiming at finding clinical efficacy and outcome of IGF-1-related therapy are of great interest. We look forward to the development of new IGF 1 therapies with minor side effects. In this review, we discuss the latest literature data regarding the function of IGF-1 in the CV system in the physiological and pathophysiological conditions.

Serum nitric oxide levels correlate with quality of life questionnaires scores of hypothyroid females.

Primary hypothyroidism can affect lipid metabolism, cardiovascular (CV) function, and overall patients' quality of life (QoL). Decrease in serum nitric oxide (NO) levels could promote the atherosclerosis acceleration in hypothyroid patients. Our hypothesis is that serum NO level is altered in hypothyroidism; more specifically, we hypothesize that the early vascular changes that can be observed in hypothyroidism could be due to these alterations and that serum NO levels are associated with lipid levels in female patients diagnosed with subclinical hypothyroidism (SCH) or clinical hypothyroidism (CH). Furthermore, since serum NO level is an early marker of atherosclerosis and related CV disorders, which are commonly present and follow hypothyreosis and greatly contribute to overall QoL, we further hypothesized that NO level would correlate with Thyroid Symptom Questionnaire (TSQ) and General Health Questionnaire 12 (GHQ12) scores in hypothyroid patients. A collaterally of our hypothesis was that levothyroxine (LT4) treatment would affect serum NO levels as well as TSQ and GHQ12 scores. Therefore, we have analyzed lipid profile, the level of NO and QoL scores in female patients diagnosed with SCH and CH in order to determine the correlation between NO and generic and thyroid disease symptoms in treatment naïve SCH and CH patients and after LT4 treatment and laboratory euthyroidism achievement. As a consequence of our hypothesis is that measurement of serum NO level in SCH and CH patients may be an innovative way to improve LT4 treatment efficacy. This assumption could have a practical significance for future investigations regarding the management of hypothyroidism treatment protocols in current guidelines.

High-Sensitivity C-Reactive Protein and Statin Initiation.

The assessment of cardiovascular risk and treatment of cardiovascular diseases are major public health issues worldwide. Inflammation is now recognized as a key regulatory process that links multiple risk factors for atherosclerosis. The substantial number of patients having cardiovascular events lack commonly established risk factors. The utility of high-sensitivity C-reactive protein (hsCRP), a circulating biomarker related to inflammation, may provide additional information in risk prediction. This review will consider the impact of hsCRP level on initiation of statin therapy.

Addition of a Fluoride-containing Radiopacifier Improves Micromechanical and Biological Characteristics of Modified Calcium Silicate Cements.

INTRODUCTION: Calcium silicate cements (CSCs) with the addition of nanohydroxyapatite and calcium carbonate play a critical role in dental applications. To further improve their properties, particularly radiopacity and biointeractivity, the fluoride-containing radiopacifier ytterbium trifluoride (YbF3) was added to their composition, and biological and mechanical characteristics were evaluated. METHODS: YbF3 was added to 3 different CSCs: cement I (CSC + calcium carbonate), cement II (CSC + nanohydroxyapatite), and Portland cement. Material characterization encompassed measurements of pH, calcium, ytterbium, and fluoride ion release; radiopacity; setting time; porosity; microindentation properties; wettability; and Fourier transform infrared spectroscopic, x-ray diffraction, and scanning electron microscopic analyses. Osteoblast- and osteoclast-like cells were grown on the materials' surface to evaluate their adherence. RESULTS: The addition of calcium carbonate, nanohydroxyapatite, and 30 wt% of YbF3 improved radiopacity and the setting time of experimental cements. The pH values did not differ among the groups. The greatest ytterbium and fluoride releases occurred in the Portland cement + YbF3 group. Combined x-ray diffraction and Fourier transform infrared spectroscopic analysis showed the presence of calcium hydroxide and calcium silicate hydrates. In addition, the presence of calcium ytterbium fluoride and ytterbium oxide proved that YbF3 reacted with cement compounds. Wettability of cement I + YbF3 was superior to other formulations, but its porosity and microindentation properties were weaker than in the Portland cement + YbF3 mixture. Cement II + YbF3 presented micromechanical indentation and porosity characteristics similar to the Portland-based cement formulation. Osteoclast- and osteoblast-like cells adhered to the cements' surfaces without alteration of the cell structural integrity. CONCLUSIONS: YbF3-containing CSCs with nanostructured hydroxyapatite and calcium carbonate are well suited for dental application.

A Comparative Analysis of the Corrosive Effect of Artificial Saliva of Variable pH on DMLS and Cast Co-Cr-Mo Dental Alloy.

Dental alloys for direct metal laser sintering (DMLS) are available on the market today, but there is little scientific evidence reported on their characteristics. One of them is the release of ions, as an indicator of the corrosion characteristics of a dental alloy. Within this research, the difference in the elution of metals from DMLS and cast (CM) samples of Co-Cr-Mo dental alloy in saliva-like medium of three different pH was examined by inductively-coupled plasma mass spectrometry (ICP-MS). The obtained results show that the metal elution in artificial saliva from the DMLS alloy was lower than the elution from the CM alloy. The release of all investigated metal ions was influenced by the acidity, both from the DMLS and CM alloy, throughout the investigated period of 30 days. The change in acidity from a pH of 6.8 to a pH of 2.3 for the cast alloy led to a higher increase of the elution of Co, Cr and Mo from CM than from the DMLS alloy. The greatest release out of Co, Cr and Mo was for Co for both tested alloys. Further, the greatest release of all ions was measured at pH 2.3. In saliva of pH 2.3 and pH 4.5, the longer the investigated period, the higher the difference between the total metal ion release from the CM and DMLS alloys. Both alloys showed a safe level of elution according to the ISO definition in all investigated acidic environments.

Morphological and biomechanical features of the temporomandibular joint disc: an overview of recent findings.

The temporomandibular joint is a type of synovial joint with unique structure and function. Between the mandibular condyle and the mandibular fossa there is a dense fibrocartilaginous oval articular disc, temporomandibular joint disc. This disc serves as a nonossified bone, thus permitting the complex movements of the joint, and plays a major role in jaw function by providing stress distribution and lubrication in the temporomandibular joint. Pathological mechanical loads are one of the principal causes of temporomandibular joint disc displacement. There is a high frequency of temporomandibular joint disc disorders and treatment options are very limited. For this reason, it is necessary to examine possible alternatives to current treatment options like physiotherapy, drugs, splints or surgical techniques. Recent discoveries in the field of structure and functions of temporomandibular joint disc have created the need for their particular systematization, all in order to create an implant that would be used to replace the damaged disc and be more similar to the natural one. There is a need to more fully meet the morphology and biomechanical properties of the temporomandibular joint disc, and using tissue engineering, make a substitute for it, as faithful as possible, in a case where the natural TMJ disc is damaged so much that the normal function of the joint can be preserved only through implanted disc. Therefore, the aim of this paper was to describe morphology and structure, as well as biomechanical properties of the TMJ disc, in light of the possible applications of this knowledge for the purposes of tissue engineering.

An in vitro radiographic analysis of the density of dental luting cements as measured by CCD-based digital radiography.

OBJECTIVE: According to the ISO, the radiopacity of luting cements should be equal to or greater than that of aluminum. The aim of this in vitro study was to determine the radiopacity of 13 commercially available dental luting cements and compare them with human enamel and dentin. METHOD AND MATERIALS: Five classes of luting cements were evaluated: zinc phosphate (Cegal N and Harvard Zinc Phosphate), zinc polycarboxylate (Harvard Polycarboxylate and Hoffmann's Carboxylate), glass ionomers (Ketac Cem Easymix, Ketac Cem Radiopaque, and Fuji I), resin-modified glass ionomer (Rely X Luting), and resin cements (Multilink Automix, Variolink II, Speed CEM, Rely X Unicem Automix, and three shades of Variolink Veneer). Tooth slices served as controls. Five specimens of each material measuring 8 mm in diameter and 1 mm thick were prepared and radiographed alongside tooth slices and an aluminum stepwedge using a Trophy RVG sensor. The radiopacity values were expressed in mm Al and analyzed by the ANOVA and Tukey tests (P < .05). RESULTS: All the cements examined except Variolink Veneer had significantly higher radiopacities than that of dentin. Rely X Unicem Automix, glass ionomer, and resin-modified glass-ionomer cements demonstrated radiopacities that were not significantly different with respect to enamel. Zinc phosphate, zinc polycarboxylate, and three of the resin cements presented radiopacity values that were significantly greater than that of enamel. CONCLUSION: Almost all the investigated materials presented an acceptable radiopacity. Radiopacity of dental cements seems to depend more on the presence of elements with high atomic numbers than on the type of the material.

[Three dimensional mathematical model of tooth for finite element analysis].

INTRODUCTION: The mathematical model of the abutment tooth is the starting point of the finite element analysis of stress and deformation of dental structures. The simplest and easiest way is to form a model according to the literature data of dimensions and morphological characteristics of teeth. Our method is based on forming 3D models using standard geometrical forms (objects) in programmes for solid modeling. OBJECTIVE: Forming the mathematical model of abutment of the second upper premolar for finite element analysis of stress and deformation of dental structures. METHODS: The abutment tooth has a form of a complex geometric object. It is suitable for modeling in programs for solid modeling SolidWorks. After analysing the literature data about the morphological characteristics of teeth, we started the modeling dividing the tooth (complex geometric body) into simple geometric bodies (cylinder, cone, pyramid,...). Connecting simple geometric bodies together or substricting bodies from the basic body, we formed complex geometric body, tooth. The model is then transferred into Abaqus, a computational programme for finite element analysis. Transferring the data was done by standard file format for transferring 3D models ACIS SAT. RESULTS: Using the programme for solid modeling SolidWorks, we developed three models of abutment of the second maxillary premolar: the model of the intact abutment, the model of the endodontically treated tooth with two remaining cavity walls and the model of the endodontically treated tooth with two remaining walls and inserted post. CONCLUSION: Mathematical models of the abutment made according to the literature data are very similar with the real abutment and the simplifications are minimal. These models enable calculations of stress and deformation of the dental structures. The finite element analysis provides useful information in understanding biomechanical problems and gives guidance for clinical research.