Volume 53, Issue 1

Abstract: The use of Additive Manufacturing methods in the manufacture of custom implants and the development of new biocompatible materials that can be processed by Selective Laser Sintering Technology, represent a trend in biomechanics. In this study two types of biomaterials were analysed and tested – PA 2200, the most used material for cranioplasty, obtained at different laser powers and polymethyl-methacrylate (PMMA). In order to analyse the mechanical behavior of the evaluated materials, the mechanical tests were made for tension, flexure and compression. It was found that the values for PA 2200 material are within the limits of the mechanical characteristics required for cranioplasty implants.

Abstract: The success of an endodontic material depends on its sealing ability, as most post-treatment endodontic disease usually occur due to marginal leakage in the apical area of the root canal. The aim of our study is to evaluate the sealing ability of a Mineral Trioxide Aggregate-based endodontic sealer (ProRootMTA), compared to other frequently used materials, on extracted human teeth, using a dye penetration leakage test. The results showed a significant difference (p[0.01) between ProRoot MTA and the other two sealers.

Abstract: The paper presents a method for elaboration and characterization some chitosan-gelatine membranes with different collagen-gelatine mass ratio, cross-linked with glutaraldehyde (GA) and coupled with extract plants. The aqueous extracts obtained from these plants were analyzed in terms of biologically active substances content (amino acids, polyphenols and phytosterols). The investigation for all obtained membranes involves: SEM microscopy, porosity, degradation test, contact angles measurement, hemolisys and antibacterian index determination.

Abstract: This paper analyses the influence of carbon filler content over the mechanical properties of vinyl ester nanocomposite. The carbon fillers used in this study were graphite and graphene nano sized particles in the following weight percentage: 0.10, 0.15 and 0.20. The mechanical properties such as modulus of elasticity, flexural stress and flexural strain were determined using three point bending tests.A significant enhancement of overall mechanical properties were achieved for some of the nanocomposite materials studied.

Abstract: This paper deals with an innovative technique regarding the embedding of biliary stones in plastic materials as an alternative and viable solution for increasing their mechanical resistance during processing for preparing the samples for instrumental analysis. The human gallstones provided from a single patient were embedded in two different polymeric plastics. The samples were investigated for their mechanical resistance under surface grinding using a rotating abrasive wheel on a bench grinder, as well lathing on a lathe machine. A discussion for the best method of embedding and the sample preparation is presented.

Abstract: In this paper we have studied the influence of discontinuities on elastic and mechanical properties of composite materials reinforced with woven Carbon, Carbon-Kevlar and Kevlar. In addition, we have studied the way variations of the volume proportion of reinforcement influences elasticity modulus and tensile strength for the studied composite materials. In order to appreciate the property difference between different areas of the composite material and also the dimensions of the defective areas, a relative uniformity influence coefficient was introduced offering us a tool for assessing the mechanical behaviour of the studied composite compared with a reference composite. We have also performed experimental validations of the obtained theoretical results.

Abstract: The paper analyses the effect of oxides powder deposition by plasma spraying and remelting with laser beam on the cavitation resistance of Ti-6Al-4V biphasic alloy. The deposited and remelted coatings were tested for cavitation erosion on the magnetostrictive vibratory apparatus with nickel tube. Using optical and scanning electron microscopy, were obtained qualitative informations about the degradation mechanism and the cavitation erosion evaluation was done by comparing the specific erosion curves of Ti-6Al-4V substrate with those of coated layers.

Abstract: This paper presents the effect of reinforcement for styrene-butadiene and styrene-isoprene block copolymers with bentonite in correlation with morphology biphasic thermoplastic elastomers.

Abstract: This paper presents the results of the research carried out in order to establish the optimum technology of polypropylene pipes, analysed from the point of view of temperature, time and labour press. Analysing the values obtained in the practical samples, the graphics of variation of components after assembly were traced, decreasing the diameter of the pipe after the assembly, the parameters that define significantly the quality of the assembly. The need to address such themes derived from the fact that in the literature, in the present time there are not sufficient and relevant information with regard to the assembly of pipes and connectors of PPR, most of the information being provided by the manufacturers and they are confined to the indication of the parameters of the assembly process.

Abstract: In this study, the static and dynamic properties of LLDPE/RH composites, with different filler contents of 5 wt% RH, 10 wt% RH, 15 wt% RH, 20 wt% RH and, 30 wt% RH were studied at different levels of strain rates (0.001/s, 0.01/s, 0.1/s, 650/s, 900/s and 1100/s) using a conventional Universal Testing Machine and Split Hopkinson Pressure Bar apparatus, respectively. Results show that the strength, stiffness and yield behavior of LLDPE/RH composites were strongly affected by both filler content and strain rate loadings. Apart from that, the rate of sensitivity of LLDPE/RH shows sgreat dependency towards applied strain rate, where it was increased with increasing strain rate. Unfortunately, the thermal activation values show contrary trend. Besides, at dynamic loading, the fracture surface analysis of the composites showed that all specimens experienced massive plastic deformation.

Abstract: The impact of pressure-assisted thermal processing (PATP) on selected polymeric food packaging materials was studied. Two commercially available packaging materials called APP (combination of biaxially oriented and PVdC coated polyester with a sealing layer against polypropylene) and BPE (combination of biaxially oriented polyester with coextruded barrier film of the structure polyethylene/EVOH/m-polyethylene) were pressurized at 600 MPa for 10 min, at 70°C. The impact of combined pressure-heat treatment on the change of packaging materials was assessed by SEM (Scanning Electron Microscopy). In addition, visual examination was performed for the treated APP and BPE materials. The results showed that the combined extreme pressure-heat treatments can compromise the integrity of both packaging materials. Opaque areas, delaminations and dark spots were a general consequence of the pressure-assisted thermal processing of tested packaging materials.

Abstract: Replacing weak soil layer by a gravel cushion is a usual consolidation method, wich has been improved lately by inserting in the gravel cushion reinfocements, analogical to concrete reinforcement, aiming to increase the bearing capacity of the foundation soil. This paper presents some aspects regarding geosinthetical materials behaviour used to reinforced the gravel cushion as much as the effect on stresses distribution and displacements in gravel and surrouding soil. This study has been conducted trough experimental tests and numerical analysis. The conducted analysis is statical and nonliniar. The calculus of the study consists of: displacements of the soil, the values of the stresses in inner part of the gravel layer and in the geosinthetic materials. Noticing that the disposal of the reinforcements leads to decrease stresses and displacements values at the foundation level but also at the gravel layer base.

Abstract: The purpose of this study is associated to the investigation of the acrylic teeth denture base resin interface with invasive tests such as tensile testing. 30 large size artificial acrylic first upper molars (Spofadent Plus_Spofa Dental) were milled to 30 acrylic cylinders. The cylinders were randomly assigned in three experimental groups, so that 10(ten) cylinders were distributed to each one of the three (3) experimental sample groups. The bonding flat surfaces of the cylinders were submitted to a different treatment: Group 1: (control group_without treatment), Group 2: Benzene, Group 3: Toluene. For the chemical treatment procedures, organic solvents with 98.9% chemical purity were used. The bonding test samples were realized according to ADA specification No. 15, using a self-cured denture base repair resin (Duracryl–Spofa Dental, Kerr Company). Each sample was stored for 30 days in distilled water and in tensile tested at 1 mm/min speed. The mean values of the tensile bond strength test registered were statistically significant among groups, ranging from 26.5 MPa (group 1) to 23.13 MPa (group 3). The results of this study suggest the fact that the chemical treatment with the mentioned organic solvents improves not in a significant manner the adhesion of the acrylic teeth to the denture base resin.

Abstract: The effects of stearic acid treated dolomite (Sa-Dol) on the mechanical, morphological and thermal properties of polypropylene (PP) composite were studied. Prior treatment, raw dolomite was ground in planetary mill using different grinding time to obtain the submicron size (under 10mm). Particle size and specific surface area of dolomite was analyzed and validated using particle size analyzer (Malvern Mastersizer) and Brunauer-Emmett-Teller (BET) method respectively. Dolomite with five filler loadings (5, 10, 15, 20 & 25%) were mixed with PP thermoplastic and were compounded using hot melt blending method. Fourier Transform Infrared (FTIR) spectroscopy confirms the successful of filler treatment using stearic acid according to the new peak at 2917 cm--1 attributed to the alkyl group that represented the addition of C-H bond. Tensile properties indicated that tensile strength of PP/Dol decreased with the increasing of filler loading for both systems. The elongation at break decreased with filler loading and showed better and improved result after treatment with stearic acid. The incorporation of stearic acid coated filler into PP matrix enhanced the break elongation of the composites that makes the composites more ductile. Morphological analysis using Scanning Electron Microscopy (SEM) proved better interfacial adhesion and less agglomeration of dolomite filler after treatment with stearic acid at low filler loading (5 wt.%).

Abstract: The purpose of this study was to determine the three-dimensional coating thickness of two scan sprays used in labside digitalization. An assembly consisting of a CoCr tooth with a standard full ceramic crown preparation and a three-dimensionally printed PLA base was duplicated twenty times out of type IV plaster. The plaster models were digitized using a three-dimensional scanner and reference virtual models were acquired (REF). A homogenous coat of spray A was applied on all models and the models were rescanned. After digitalization, the models were steam cleaned and the same technique was used for spray B. The reference scans were compared separately with the scans of group A and B. The resulting data was analyzed with the Student unpaired t-test (a = .05). While there were significant intergroup differences in the three-dimensional comparison of the root mean square of deviations, both scan sprays showed acceptable coating thicknesses for clinical use.

Abstract: This investigation concerns the preparation of binary PPR/SEBS and PPR/SBS blends by melt mixing procedure with the goal of studying the effect of thermoplastic elastomers on performance of polypropylene random copolymer (PPR) in the extrusion and injection molding processes. Effect of poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) and poly(styrene-b-butadiene-b-styrene) (SBS) respectively on the mechanical and thermal properties of PPR have been investigated. The melt processability, melt flow index (MFI), tensile properties, VICAT softening temperature (VST), heat deflection temperature (HDT), Shore hardness and IZOD measurements highlighted that SEBS is more efficient than SBS.

Abstract: The paper concerns current engineering in plastics processing, the present day studies focusing on the rational solving of problems and on logical reasoning, on the usage of modern mathematical methods in leading and taking decisions, on the usage of instruments which have significantly changed and the development of business: computers, the internet, artificial intelligence. The practice uses engineering techniques by creating mathematical models. Appealing to scenarios ensures the improvement of decisions, involving answers on the improvement of quality and the rational usage of available human and financial resources. The research results are materialized through the development and effective use of a mathematical model in which the incoming data packets are obtained at a quantifiable levels of risk.

Abstract: The obturators are prostheses used to close palatal defects after maxillectomy, to restore masticatory function and to improve speech, deglutition and esthetics. The most commonly used materials in manufacturing maxillary obturator prosthesis are the acrylic resins. The aim of the paper is to present experimental compression and traction tests in order to determine the material properties of Meliodent® Heat Cure produced by Heraeus Kulzer GmbH Germany. This is a two component heat curing polymer used for manufacturing fixed and removable prosthetic devices. Test results show that the average compressive strength of the samples is 94 MPa, while the average compression modulus for all resin samples tested was calculated at 716 MPa. The average ultimate tensile strength of the samples is 58.72 MPa and the average modulus of elasticity for all resin samples tested was determined to be 4213 MPa.

Abstract: The loss or absence of an eye creates not only a functional disability, but also an important psychological impact on an individual’s social and professional life. Ocular prostheses are maxillofacial prosthetic devices which are generally custom made to replace a lost eye. Polymethyl methacrylate (PMMA) is the most common material used for manufacturing ocular prostheses. The main component of the ocular prostheses is the artificial iris that needs to be identical to the healthy one. For this reason manufacturing the iris is a challenging task for the maxillofacial anaplastologist. The main procedure used in manufacturing the iris is the manual painting technique which can be time consuming and susceptible to error, mainly regarding the color matching. The subject of this article describes an alternative technique of manufacturing the iris. This technique involves using a digital photographing image of the healthy eye which is edited and printed on photographic paper and it seems to offer good esthetic results being less complicated compared to the conventional manual painting technique. The main deficiency of the method is the color distortion which appears after the iris is embedded in the ocular prosthesis. This is caused by an alteration of the photographic paper during the final polymerization stage of the ocular prosthesis which takes place at high temperature.

Abstract: Tracheal stenosis is a condition where the trachea narrows or becomes constricted as a result of a laryngotracheal trauma, prolonged tracheal intubation, high tracheostomy or systemic diseases.A possible treatment for tracheal stenosis is tracheal reconstruction with costal cartilage grafts that are implanted into the anterior tracheal wall. In order to secure the graft cartilage to the tracheal sidewalls we can use differnt synthetic resorbable materials, such as polylactic acid and polyglycolic acid, that allow anchoring of the costal cartilage to the tracheal wall. The aim of this paper is to present a fixation device for fixing the cartilage graft on the tracheal side walls. This device is designed using a synthetic resorbable material and allows anchoring of the costal cartilage to the tracheal wall using microscrews made of resorbable material.

Abstract: In this study, the alkali treatment of sawdust (SD) using different concentration (1%, 3%, 5%, and 7%) of sodium hydroxide (NaOH) was performed. The phases change due to alkali treatment on sawdust particles was examined using Fourier Transform Infrared (FTIR) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). Result shows that the treatment with 5% NaOH on sawdust particles improved the surface roughness of the filler with 21.1 % diameter reduction. Both treated and untreated sawdust particles were reinforced in HDPE matrix using an extrusion method. For comparison purpose, both treated and untreated high density polyethylene/sawdust composites were tested under static and dynamic loading up to 1100 s-1 using the universal testing machine and the split Hopkinson pressure bar apparatus, respectively. Results indicate that the treated high density polyethylene/sawdust composites with better filler/matrix interlocking characteristic shows better mechanical performances as compared to untreated high density polyethylene/sawdust composites under a wide range of strain rate investigated. Apart from that, the mechanical properties of both treated and untreated polyethylene/sawdust composites also show great dependency on the strain rate applied where yield stress, compression modulus and ultimate compressive strength were steadily increased with increasing strain rate. Unfortunately, the yield strain shows the contrary trend. While for the fractographic analysis under dynamic loading, the untreated composite specimens had undergone a severe catastrophic deformation and damages than that of treated composite specimens.

Abstract: The oral cavity can be considered a complex biomechanical system. Most researches about oral environment’s biomechanics, related to restorative dentistry, endodontics, orthodontics, prosthodontics and implantology are conducted in vitro. Applying the principles of engineering in dentistry contribute significantly to understand aspects of oral biomechanics. We conducted comparative research by finite element method on mixed prosthetic restorations with metal frame of CoCr and NiCr, subjected to the same experimental occlusal loading to determine what type of metal substrate has a better biomechanical behavior.When applying forces in the frontal region, the area of weakness is, according to carried out analyzes, disto-incisal angle of the lateral incisor and at the application of forces in the lateral region, the most vulnerable is disto-palatal cusp of the second molar. Overall, for the particular case analyzed, it is recommended to make metal-ceramic prosthetic restoration with metal support of CoCr, which is less distorted and strained at the experimental application of masticatory forces, compared with metal-ceramic restoration made of NiCr.

Abstract: The literature highlights the use of nanoparticles for the treatment of wastewaters containing organic compounds such as hydrocarbons, phenols, etc. The oxidation process of pollutants in wastewater from catalytic cracking was performed on nanostructured catalysts based on Fe, Mn and Fe-Mn mixed. The catalysts were prepared by precipitation-coprecipitation in the presence of anti-caking. Measurements for the determination of particle size distribution were carried out using the method of dynamic light scattering. The oxidation process was conducted in a batch reactor equipped with air bubbling system, in suspension of catalysts at a concentration of 1%, a temperature of 85-90o C, pH 9.2, for a period of 2h, 4h and 6h respectively. The best results were obtained in the presence of Fe - Mn catalyst at 6 hours reaction time. Degree of contaminant removal for this catalyst had maximum values of 72.80% for COD, 77.97% for extractible, 74.4% for phenol, 67.53% for ammonium and 67.57 % for sulfides,. Better behavior of Fe - Mn catalyst in the oxidation reaction was due both to the nature of the catalyst, as to well as the smaller size of this catalyst particles.

Abstract: The purpose of the study is to assess and compare the effects of different antiseptic mouthrinse solutions on traditional glass-ionomer cements. Thirty samples of three traditional glass-ionomer cements used for base: Ketac Molar Easymix (3M ESPE), for restoration: Fuji IX (GC Corporation) and for sealing: Fuji Triage (GC Corporation) were included into three groups. In group 1, the samples were immersed for 14 days, twice a day one minute each, in Listerine Cool Mint, in group 2 the samples were immersed for 14 days, twice a day one minute each, in Parodontax Extra in group 3, the samples were immersed for 14 days, twice a day one minute each, in Sensodine Cool Mint. In control group the samples were immersed in artificial saliva. Within each group, sub-groups were established according the time of cement ageing (one day,seven days and fourteen days). The samples were analyzed for surface topography using a scanning electron microscope and for chemical composition using EDX detector. The antibacterial mouthrinse solutions Listerine, Parodontax, and Sensodine have an erosive effect on traditional Fuji IX, Ketac Molar and Fuji Triage glass-ionomer cements. The most affected cement by erosive action was Ketac Molar, followed by Fuji IX and Fuji Triage. All three glass-ionomer cements tested in this study proved to be more resistant to erosive action after their ageing.

Abstract: The aim of study was to evaluate some aspects in the clinical effectiveness of fibre-reinforced composite resin periodontal splints on mobile teeth. Fibres-reinforced composite resin retainers are recommended likewise in the treatment of teeth mobility. The study group was formed by a total of 62 patients, which presented first and second mobility degrees of anterior teeth (436 included teeth into research). 42 patients belonging to the experimental group with periodontal splinting, benefited by Interlig-Angelus glass-fibers and Ribbond-Seattle polyethylene-fibres reinforced composite resin splints (295 splinted teeth and 50 splints). The used composite resin was represented by Vertise™ Flow-Kerr. 20 patients (141 teeth) represented the control group, without splinting. All included patients followed periodic monitoring visits (after a week and at one month, for a period of 6 months), in order to evaluate the detaching degree/adhesive failure of reinforced composite resin splints and the reducing of dental mobility degree. The results of study revealed that between the two types of immobilization splints there was no significant difference in the degree of separation/adhesion failure, in the acceptability or in the patient s comfort. Both types of fiber-reinforced composite resin periodontal splints had beneficial effects in decreasing the degree of dental mobility and it was remarked their aesthetic acceptability, respectively the patient s comfort.

Abstract: The bile duct system has one intrahepatic and as well extrahepatic distinct components, both subject to large anatomical variability. The left component of the bile duct is much more rarely when compared with than the right side. On the 100 pieces of hepatic corrosion casts, we analysed the confluence modality of II, III and IV segmental ducts, to form the lateral and medial branches, and finally the left hepatic duct. Depending on the confluence modality of these ducts and branches to form the left hepatic duct, we revealed three morphological types. In the majority of cases (Type I - 86% of cases) the confluence of segmental duct II and segmental duct III form the lateral branch and the confluence of lateral and medial branches form the left hepatic duct. In most of these cases, the confluence of segmental ducts II and III (to form the lateral branch), is located on the left side of the lateral portal branches origin branches origin, and the confluence of lateral and medial branches (to form the left hepatic duct) is located at the right of the origin of the medial portal branches. Relations of the intrahepatic biliary ducts system with the portal vein element have major practical importance in liver resection surgery and transplantation.

Abstract: This research aimed to assess properties of emulsions containing various concentrations of collagen hydrolysate produced from calf skins. The most optimum variant of collagen separation from calf skins was used, developed by these authors. The resulting aqueous collagen hydrolysate was employed to produce oil/water cosmetic emulsions containing from 1 to 8 wt % of hydrolysate. Hydration and sensory properties of the proposed substances were evaluated. Appearance and rubbability of the emulsions and washability of make-up were determined. Emulsions containing collagen hydrolysates were assessed by respondents of two age brackets: 18-35 and 36-55. Stability of the emulsions was appraised using centrifuge and temperature testing. On application of these preparations, the skin was highly moistened, particularly in the older respondent group. Consistency of the emulsions was homogeneous and free from clotting. The work confirmed that part of hides constituting the waste can be a potential source of collagen used as an anti-ageing ingredient of cosmetic emulsions.

Abstract: The field of cartilage repair and restoration has expanded a lot in the last decade since articular cartilage problems are very common. As a consequence, many biomaterials were created in order to aid physicians in treating different osteochondral defects. Polymers like polyurethanes or PGA-hyaluronan have been frequently used as the in vivo cartilage tissue repair solution, as reported in animal studies and in clinical applications. Three different implants (Agili-C, Hyalograft C, and Chondrotissue) were used in 23 patients (6 medial and 17 lateral lesions) in this study. Patients were assessed at 3, 6, 9, and 12 months postoperative follow-up visits using the International Knee Documentation Committee (IKDC) scores and Knee injury and Osteoarthritis Outcome Score (KOOS). The follow-up assessments demonstrated clinically and statistically significant improvements (p < 0.05) in all clinical outcome scores, as compared to the respective preoperative values: IKDC (48.9/77.1 for Chondrotissue implants), KOOS symptoms (58.2/71.9 for Agili-C implants), KOOS pain (54.8/66.1 for Agili-C implants), KOOS daily living activities (64.2/76.3 for Agili-C implants), KOOS sports (38.3/60.8 for Agili-C implants), KOOS quality of life (40.1/60.7 for Agili-C implants) demonstrating improvements in the case of implants previously mentioned. The overall results of this study support the successful use of the Agili-C, Chondrotissue and Hyalograft-C implants for the treatment of knee cartilage lesions.

Abstract: Phytochemicals are biologically active chemical compounds found in plants. They were identified as displaying bioactivity in the prevention of cancer, heart disease and other diseases. The most important classes of phytochemicals are: polyphenols, carotenoids, essential oils, phytosterols etc. The encapsulation of phytochemical compounds in different matrices is required in order to prevent the degradation of phytochemical compounds under the influence of some factors such as oxygen, light radiations, pH and high temperature. Biopolymers with new functional properties, i.e. biodegradable, biocompatible and stimulus responsive, have been tested for encapsulation of phytochemicals bioactive. In this review, we are showing the most important biopolymer classes used as wall in the preparation of drug and food phytochemicals micro and nanoparticles.

Abstract: A new dye-sensitized solar cell (DSSC) counter electrode was obtained through the electropolymerization of the monomer 3.4-Ethylendioxythiophene (EDOT) directly onto a indium tin oxide (ITO) coated glass in the presence of an aqueous titania nanotubes (TiO2 NTs) suspension. The TiO2 nanotubes in the anatase phase were incorporated in the conductive polymer film, being also observed an increase in the catalytic activity and the fill factor of the assembled device when using the under examination counter electrode.

Abstract: In an Ameloblastoma case we used CT data to create a 3D representation of the affected mandible and Finite Element Analysis allows us to study its behavior under masticatory forces. In this manner is possible to better understand case evolution and to decide the treatment plan, specific for each patient.

Abstract: Additive Manufacturing (AM) is rapidly becoming a common practice within the medical industry. Used for applications such as tools and devices, custom implants, scaffolds or even organ printing, AM technologies have already started to improve medical practice, patient care management and treatment outcomes. The authors developed a concept for a custom intervertebral fixing implant starting with the medical data of a specific patient. The proposed bespoke implant replicates identically the anatomical features and caters to particular conditions of the patient in cause. The implant was designed in correspondence with the cervical spine using specialised medical software. Several triangle based analyses were used in order to evaluate the adequacy of the *.STL files before 3D printing. Film Transfer Imaging technology was used to manufacture both the anatomical model of the cervical spine and the bespoke spinal implant concept. The parts were presented to surgical specialists for through fitting evaluation and testing. Feedback and recommendations were given in terms of additional support and fixing. Surgical procedure tests were recommended on an explanted animal cervical spine.

Abstract: Trace level detection of drugs is routinely monitored in toxicology laboratory. Whole blood testing is an essential component in evaluation the nature and the concentration value of the ingested drug prior to initiate the therapy. One of the most important steps in lab working protocol regards collection and pipetting technique for whole blood assay. The aim of the study was to compare the effects of whole blood collection and pipetting technique for cocaine and its major metabolite (benzoylecgonine) in trace level assay. The results evidenced that by using both glass and plastic tips, concentration values were lower when using polymeric tube for collection and plastic tips for pipetting compared to glass tubes and plastic tips. In the case of glass containers, the higher concentrations were obtained when using glass pipette. The lower values can be caused by blood adherence to the inner circumferential surface of the pipette tip.

Abstract: The aim of this study is to individualize from the structural point of view the silicon materials which lay at the basis of the manufacturing the oral mouth guards in full accordance to the features of the subject who is going to benefit from these devices, a highly important role belonging to the maxillary architecture and the occlusion type. Choosing the election biomaterial for the oral protection gear was done based on mathematical modelling using the Abaqus Standard system, with the aim of evaluating the tensions transmitted at the jaw level by different types of biomaterials which are embedded in the structure of these devices. The biomaterial represents an alternative favorable for the oral protection gear given the degree of elasticity and the possibility of including an antiseptic material, such as Eugenol, important features which individualize it.

Abstract: Plastination, as technique, is a laboratory method used for preservation of biological structures in order to complete comparative morphological studies and for research. The resulted specimens are used in teaching and learning anatomy. The budget for the standard plastination technique S10 and for materials used in the first stand is limited. In addition, the location and the facilities are simple and required special arrangements and authorization. The difficulties and inconvenience of developing the laboratory for plastination S10 technique in the Anatomy department, Faculty of Veterinary Medicine of Timisoara is reported.

Abstract: The aim of our study was to compare micro-morphological changes in enamel surfaces after etching for 60 or 120 s by 37% phosphoric acid gels. Eighteen extracted, not carious human teeth with sound buccal surfaces were obtained, thoroughly cleaned with a water slurry of pumice powder, with a soft rubber prophylaxis cup rotating at low speed and stored in saline at room temperature. After the teeth were sectioned longitudinally in mesio-distal direction using a low-speed bur, the enamel was etched with 37% phosphoric acid (Lucstar, Romania) for 60s and 120s with applicator sponges, rinsed with water and sprayed with air for 15 s, and dried for another 15 s. Each section was evaluated under the microscope and photomicrographs were taken of representative areas that were most often observed using statistical analysis. The enamel surface etched with 37% phosphoric acid gels for 60 and 120 s showed similar etching patterns. No evident morphological differences were observed in the type of enamel etching patterns when treated with 37% phosphoric acid gels for 60 and 120 s. However, etching with 37% phosphoric acid gel for 60 s resulted in a partial removal of the prism core and the micro-morphological characteristics of the enamel surface approached those produced by 37% phosphoric acid gels used for 120 s. Phosphoric acid gel used at concentrations of 37% produced similar micro-morphological etching patterns on enamel surfaces after 60 or 120 s of application.

Abstract: Milling is a very common process in the manufacture of plastic parts. In a technological process, milling may be the final procedure, consequently influencing the quality of the product. To determine the optimum processing conditions, it is necessary to make an accurate model of the forces in order to describe the process in terms of cutting parameters. Experimental research has been conducted on the influence of the cutting parameters on the milling cutting force components. This paper aims to obtain the equations that define the variation of the cutting force components by the milling process parameters in the processing of specimens of polyamides (PA66, PA66-GF30 and MoS2. These polyamides belong to the class of technical plastics and are thermoplastics with excellent mechanical properties, also used in the engineering industry.

Abstract: Dental sealants are a specific prophylactic alternative for fissures with an irregular morphology. The aim of this in vitro study was to evaluate dye penetration around three materials recommended for fissure sealing with a different composition. Thirty teeth were sealed according to manufacturer’s instructions as follows (n=10): Group I, light-cured unfilled resin-based sealant, Admira Seal® (Voco GmbH); Group II, light-cured filled resin-based sealant, Fotoseal® (S.C.Remed Prodimpex S.R.L., Bucharest, Romania); Group III, resin modified glass ionomer sealant without varnish, GC Fuji Triage® (GC Corporation). The teeth were thermocycled, then immersed in 0.5% basic fuchsine dye for 24 h. The teeth were sectioned buccal-lingually in order to obtain one section per tooth in the middle of the occlusal surface and the sections were examined at 40x with an inverted microscope. Dye penetration was recorded (mm) using specific software and related to the total length of the sealed fissure. Average values for each group were subjected to statistical analysis by Student’s t and Kolmogorov-Smirnov tests (p[0.05). Significantly less dye penetration was recorded for both resin-based sealants compared to the resin modified glass ionomer sealant, with no difference between the filled and the unfilled resin sealant (p=0.34). The resin-based sealants were more effective in sealing the fissures than the resin modified glass ionomer cement sealant.

Abstract: Numerous problems are seen in the general lifestyle and health of young adults with noscomially acquired HIV between 1987-1990, a peculiarity of the HIV infection in Romania. One of these problems is immunity alteration as reflected in the oral pathology of these patients. This study evaluates the impact that the HIV infection has on the oral health of infected young adults. The current observational, case-control study compares the caries experience and the impact on oral health quality in 114 HIV positive young adults versus a control group, using the Decay-Missing-Filled (DMF) Index and the oral health profile, obtained using by OHIP-14 questionnaire method.

Abstract: This paper presents the development, operation and testing of a modular small sizes original stand, its main modules made of plastics, intended for tests on blades and rotors in the structure of experimental models of hydraulic turbines. The stand includes a water tunnel consisting of demountable and sealed sections of which the majority, of various shapes and sizes, are made of composite material type fiberglass reinforced polyester, FRP, and one of them, rectangular cross-section, is made of transparent and resilient Plexiglass. Through the shapes of sections, quality of interior surfaces and quality of plastics used, the water tunnel allows creating in its transparent section a forced, permanent and continuous circulation of water, of adjustable speed in the range 0.05 ... 1.1m/s. The results of tests conducted on an experimental model of water turbine by use of this stand demonstrate the economic and technical advantages of using plastics in building these types of testing tools.

Abstract: Equal Channel Angular Pressing (ECAP) is the most emblematic technique for producing bulk nanostructured materials and ultrafine grained materials (UFG) through severe plastic deformation. In this study, we examined a 6063-T1 aluminum alloy, subjected to ECAP processing at room temperature for one, three, six and nine passes respectively, using a 90° die and the processing route BC. The as-received and ECAP processed samples were firstly analyzed in OES experiments, the accumulated equivalent strain being also estimated based on ECAP die geometry and on the number of passes. All specimens were investigated as well in XRD tests for phase identification. Williamson-Hall method was used for evaluating the crystallite size and the lattice strain. Some correlations with the main processing parameters were also established.