Browse Articles

In our study we aimed to identify the individual influence of the main components of wine on the studied composites. The samples were immersed in water, wine, alcohol, tartaric acid solution, at 370C. We measured the reflectance of the surfaces of the composite materials with UNICAM 4 UV-VIS spectrophotometer after 24 h, 7 days and 28 days. The t test results for delta %(xnm)ts of the dental composite material at the same moment in time and different solutions (within the group test) identified a single group which revealed no statistical significant difference. The studied materials at the same moment in time (between group tests) will respond statistically different to the immersing solution. We expect that the changes in the composition of composite materials, including activation systems, inorganic fillers, resin matrix, silane will change the response of the composite materials to the immersion solutions. Keywords: dental composite materials, wine components, reflectance changes

The objective of the study was to evaluate the FGP friction fit system as alternative to other procedures for double-crown systems. FGP is a resin material that has a coefficient of friction more favourable than the metal, so it provides minimal wear and long lifetime, high patient comfort, eliminates complicated adjustments tensions arising due to metal to metal framework friction at multiple items. Keywords: FGP, resin, coefficient of friction

The tracheal bronchus (TB) in man is described only as a rare anatomical variation, known as the “pig bronchus” or “bronchus suis”. The right-sited TB is normally present in swine. One of the employed method for the training of students and medical residents is the study of corrosion casts. A TB study was conducted on a total of 20 pig tracheobronchial corrosion casts. On the studied corrosion casts the distance between the origin of the TB to carina had an average of 45.1 ± 7.81 mm. The origin range of TB at the level of the right lateral trachea was between 37 and 61 mm above the carina. The mean angle that makes TB with the right lateral trachea ws of 40.29 ± 3.90 degrees with a variation of 15 degrees, ranging between 30-45 degrees. The increasing of the distance between the origin of TB and carina is associated with the decrease of the angle that makes TB with the right lateral trachea. Use of swine tracheobronchial corrosion casts with constant presence of TB, can compensate for lack of clinical material in training of medical students and residents. Keywords: corrosion casts, tracheobronchial system; trachel bronchus, training

This paper concerns with a method for automatic detection of voids as a result of epoxy die-attach process of a semiconductor chip to the package. A radiographic image is acquired from the inspected semiconductor chip and package and image processing techniques are employed in order to automatically compute the amount of epoxy die-attach voids. Keywords: image processing, X-ray imaging, image segmentation, artificial intelligence

The aim of this study was to evaluate the topography of the main neurovascular bundle located in the posterior aspect of the shoulder and to establish a relatively safe area for a low-risk arthroscopic approach through a posterior portal. A slice anatomy study, using plastinated transparent shoulder joint sections, was performed on ten non-degenerative right shoulder body specimens. Measurements were performed at the level of the suprascapular notch, the coracoid process, and the acromion. The suprascapular nerve was 38.2 ± 0.1 mm, the suprascapular artery 39.4 ± 0.2 mm, and the circumflex scapular artery was 24.8 ± 0.5 mm away from the posterior rim of the acromion at the level of the suprascapular notch. At the level of the coracoid process the suprascapular artery was 34.2 ± 0.5 mm, and the circumflex scapular artery was 50.9 ± 0.3 mm away from the posterior rim of the acromion. Combined measurements of both arteries offered an average distance of 19.8 ± 0.3 mm. The mean distance to the posterior circumflex humeral artery and the axillary nerve was 47.7 ± 1.5 mm and 50.9 ± 0.9 mm, respectively. The present study suggests that, a posterior arthroscopic approach at a level of 4.5 to 5 cm below the posterior rim of the acromion and above the midline of the glenoid joint space poses a low risk for injuries to the neurovascular structures. Keywords: Plastinated cross-sections, arthroscopy, shoulder, axillar nerve

For the optimization of the screw and extrusion process design one need to address issues such the interdependence between the geometrical, hydrodynamic, thermal parameters and material behaviour in each screw zone along with the correlations between successive screw zones. For that purpose, the process parameters (material temperature, barrel temperature, screw speed, pressure development in the screw channel), the screw geometry (flat and compression zones) and the matter behaviour (tribological, thermal and rheological) as a function of temperature and pressure were analyzed. The interdependence between the screw design and the extrusion process parameters from a practical point of view, with the aim of designing the most suitable screw with optimal process parameters for a given processed material, was established. Keywords: extrusion; screw design; optimization; process parameters

The best tibial fixation technique in anterior cruciate ligament reconstruction remains a challenge to be solved. Due to the increased tension on the graft and the poor bone quality, the slippage of the graft is a determining factor of failure. We propose an alternative supplementary, cost-effective and reliable solution to improve the outcome of the grafts fixation. The results obtained on 10 freshly frozen porcine tibiae were significantly improved (p=0.012) compared to the standard method of fixation. The maximal and mean pull-out force was in conformity with the literature. The bones and tendons used simulates the real human ones, thus the results encourage us to extend the application of the method in clinical cases. Keywords: anterior cruciate ligament, tibial fixation reinforcement, graft slippage

This workpaper presents the assessment of the interaction between the dimension of glycol-modified polyethylene terephthalate (PETG) and the attrition of occlusal appliances by determining the degree and area of attrition of dental mouth guards made of PETG plates of different sizes: 0.8mm, 1mm, 1.2mm, 1.5mm, 2mm, 2.2 mm thick. The samples were made by thermoformed using the Erkoform device and inserted into the oral cavity subjects. The evaluation was made 2 weeks, 4 weeks and 6 weeks later. For evaluation it was used coloured occlusal spray. The best results were obtained with the 2 mm thick, but in our study the occlusal appliances with 1,2 mm had good results too. Keywords: occlusal appliances, glycol-modified polyethylene terephthalate (PETG), thermoformed

In order to obtain an ideal smile design for our today subjects, more often the dental treatment requires interdiciplinarity. Recent advances in dental materials and techniques promote the opportunity of bonding orthodontic attachments to surfaces other than enamel, like porcelain crowns, veneers, or bridges. This study aims to compare tensile bond strengths of metal brackets bonding to porcelain fused-to-metal crowns, using two different luting cements (RelyX™ Unicem U200 by 3M ESPE, respectively Blugloo by Ormco) and the same surface conditioning system, as well as to determine the findings’ statistical value. The results evaluated by ANOVA, Tukey and Kruskal-Wallis tests indicated no statistically significant differences among the two cements in terms of tensile bond strength. Keywords: metal brackets, ceramic crowns, tensile bond strength, luting cements

The specific parameters describing the flows of Bingham type rheological fluids through a circular pipe, under the action of a pressure gradient in the direction of the movement are established, using the Non-Standard Scale Relativity Theory approach. In such context, an analytical solution and a numerical application (for KELTAN 4200 — an etilene-co-propilene copolymer) are obtained. The friction effort has two components, one of specific fluid gliding, the other of shearing, depending on transverse speed gradient. In the central area of the fluid movements a particles agglomeration (fluid stopper) occurs, defined by a constantly moving structure. Keywords: rheology, friction effort, polymers, fluid stopper, speed