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Acrylic resins are widely used today both in pediatric dentistry and orthodontics for the manufacturing of space maintainers, interceptive devices or removable orthodontic appliances. All removable orthodontic appliances are composed of porous materials in which microorganisms (fungi, bacteria and viruses) infiltrate, attach and can form biofilms. For this study, two types of materials were chosen in order to test their influence on biofilm formation. For biofilm quantification a strain of Candida spp. was selected among 12 strains isolated from 23 pediatric patients, 7 to 12 years of age, wearing space maintainers or removable orthodontic appliances for at least 4 months at the time of harvest. The materials used in this experiment were the cold-cure acrylic Palapress®vario (Heraeus-Kulzer GmbH, Hanau, Germany) and the visible light acrylic polymerizable system Eclipse (Dentsply DeTrey, Konstanz, Germany). Images of the biofilm formed were obtained using a confocal laser scanning microscope. The images were analyzed using Comstat 2 software. The results showed that in both materials used, the average maximum thickness of the biofilm was above 10 µm. No significant differences were observed in biomass development of the biofilm between the two types of materials tested. Differences were observed in average thickness and maximum thickness of the biofilm. The thickest biofilm was formed on Palapress material. The biofilm formed on Eclipse material surfaces covers 66% of the total aria, while on Palapress material the biofilm covers only 40% of the total aria. These results explain why there are no differences in biomass between the biofilms formed on both materials despite the thickness and average colony size. Keywords: acrylic resins, biofilms, space maintainers, removable orthodontic appliances

The aim of this study was to assess the effect of some foods consumed previous to an erosive beverage on dental enamel and cement. The study was performed on 40 human teeth unaffected, extracted for orthodontic braces. The teeth were cut to obtain 80 cervical slices including enamel and dentine/cement areas. The slices were randomly divided in four groups. The 20 samples of control group (group 1) were submitted in 72 hours to nine demineralisation cycles (3 cycles/24 hours) by immersion in Pepsi-Cola ® for 5 min (32 mL/sample). The samples from other three groups were immersed in cheese extract (group 2), broccoli extract (group 3) and undilluted cow milk (group 4) for 5 min (32 mL/sample) previous to Pepsi-Cola ® immersion. For each group, microhardness was measured using digital device CV 400 DAT on 10 samples and surface roughness was determined on another 10 samples by profilometric method using profilometer Taylor Hobson-Surtronic 25. For each sample mean value of Vicker hardness (VH) and mean value of roughness (Ra) were calculated as a result of 5 determinations. In enamel/cement areas the mean value Ra recorded for group 1 was 3,83/3,5 times higher than mean value Ra in study group 4, 2,99/2,95 times higher than mean value Ra in study group 3 and 2,81/3,04 times higher than mean value Ra in study group 2. The mean values of VH of enamel/cement before and after immersion in the tested food varied from 389/68 VH to 235/34 VH in group 4, from 367/64 VH to 354/58 VH in group1, from 382/69 VH to 371/61 VH in group 2 and from 393/63 VH to 381/57 VH for group 3. The consumption of foods like milk, cheese and broccoli before the ingestion of erosive beverages can significantly reduce the erosion of dental enamel and cement. Keywords: erosive potential, milk, broccoli, cheese, enamel, cement

One of composite materials used in plumbing is the resin reinforced fiberglass or carbon. The most common applications in the field, refers to fluid storage tanks, piping, tubing, and given that storage tanks used in water supply systems are used to the action of the natural environment, the work deals with issues related to the influence of the external environment on behaviour in time of the composite material of a water storage tank. There are comparatively analyzed two sets of samples with 25-30% of reinforcement, made of 601 general used polyester resin reinforced with fiberglass, CSM 225, CSM 450 and Tesutino 300. The first set of samples was taken from a tank made in 2002 and exposed to the action of the external environment for 10 years. The second sets of samples was taken from a manufactured material in 2014. The research consists in determination of tensile strength after exposure period. By evaluating the tensile strength of the two sets of samples, there is comparatively analyzed the influence of the external environment on the material resistance degradation to the cumulative action of the following factors: UV, snow, rain, dust, wind. The study provides data on setting life of use of the stationary storage tanks, in safe conditions. Keywords: composite materials, tensile strength, stress, strain, storage tank

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