Browse Articles

The surgical approach of the skull base pathology is in a state of constant development. The advancement of the ablative techniques forced the development in the field of reconstructive surgery of the skull base as well. The goal of the reconstructive surgery of the postablative defect of the skull base is to create a stable, watertight limit between the endocranian and the sinusal cavities. New reconstructive materials and adhesives were developed. The purpose of this article is to critically analyze the use of the mixture between the polyethylene glycol ester and trilysine amine solution as a sealant and adhesive in the reconstructive surgery of the skull base. Keywords: polyethylene glycol ester, trilysine amine solution, skull base, reconstructive surgery

Statistical copolymers N-isopropylacrylamide (NIPAM) – 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) with different compositions were prepared by RAFT polymerization and characterized by 1H NMR, GPC and DSC analyses. Their solid-state thermal degradation was investigated for the first time by TGA, showing that the presence of the BMDO units within the PNIPAM chain decreased the thermal stability of the copolymer. In the case of higher BMDO content copolymers the onset decomposition temperature was lower even than that of PBMDO, and also a multistep decomposition process was noticed. The evolution of the global activation energy of the degradation process as a function of degradation conversion was determined by means of the Kissinger-Akahira-Sunose isoconversional method. Keywords: N-isopropylacrylamide; 5,6-benzo-2-methylene-1,3-dioxepane; copolymer; thermosensitive; thermal degradation; Kissinger-Akahira-Sunose isoconversional method

Many studies are concerning with impact properties of composite materials because their large usage in aero-spatial, automotive, marine and sport industry. As the use of composites is continuously increasing the need for more valuable materials becomes essential in designing and producing such materials for a growing market. It is well known that thermoplastic matrix composites show better impact resistance than the thermoset matrix materials but their forming technology is more expensive. This study was designed to analyse the impact behaviour of fabric reinforced thermoset polymer matrix composites with an emphasis on structure of reinforcement. The matrix is an epoxy resin (Epiphen RE4020 – DE 4020, Bostik) while the used fabrics are of carbon fibres, aramid, fibres and glass fibres. Low velocity tests were performed on materials, according to ISO N-6603, and the results were inspected by tomography. Keywords: epoxy resin, fabrics, impact tests

Obstructive sleep apnoea (OSA) is the most common sleep-related breathing disorder that is increasingly recognized as a serious public health issue. The treatment management is determined by the severity of the syndrome. Oral appliances (OAs) are increasingly advocated as a treatment option for mild/moderate obstructive sleep apnoea (OSA). The aim of this paper was to present the two main treatment solutions for OSAS through custom oral appliances made in dental laboratory and to systematically review the available studies in the literature on the efficacy of OAs. Keywords: Obstructive sleep apnea, Oral Appliances, Heat-curing Acrylic resins, Mandible advancement device, Thermoforming method

The aim of the current study was to obtain materials presenting a large scale of applications (polyurethane adhesives and foams) through a one-pot synthesis starting from post-consumer poly(ethylene terephthalate) (PET) bottles. The PET depolymerization was carried out using diethylene glycol (DEG) and catalyst (zinc acetate) in a microwave reactor. Using the obtained depolymerization mixture, different polyurethane adhesives or foams formulations were developed. The adhesives mechanical properties were tested affording samples with tensile shear resistance suitable for commercialization. The polyurethane foams testing confirmed the obtaining of rigid structure with good thermal insulation properties. Keywords: PET, microwaves, adhesives, polyurethane foams, one-pot synthesis

Crown preparation and wax pattern technique are two key factors for the success of a cemented restoration. A poor marginal fit is the main cause of plaque penetration and leakage of oral liquids enhancing thus caries and periodontal disease [1, 2] The present study compares the marginal fit of full metallic crowns restoring caries free extracted molars using different types of marginal preparation as well as different wax-up techniques. The marginal gap was analyzed using scanning technique with an electronic microscope before and after in vitro cementation in several points for every surface of each tooth. Data were statistically analyzed and compared. The scanning technique enhances measurements of the marginal gap without sectioning and provides an objective evaluation of preparation and cementation techniques. Keywords: scanning electron microscopy, marginal gap, crowns, wax pattern techniques, marginal preparation techniques

The fabrication of adsorbent textile fiber materials is of great scientific and industrial interests. In this work a new procedure for fabrication of an anionic compounds adsorbent based on polypropylene nonwoven has been described. Because of using atmospheric pressure plasma as a surface specific pretreatment, the described procedure can be considered as a convenient method without affecting the bulk properties of the fibers. Atmospheric pressure air plasma was used to produce peroxide groups on the surface of polypropylene fibers. Grafting of acrylic acid (AA) was followed to create carboxyl groups on the fibers surfaces and finally the grafted polypropylene fiber samples were aminated using diethylene triamine (DETA) to convert carboxyl groups to amine groups. The effects of various experimental conditions: such as the time for plasma treatment, monomer concentration, temperature and reaction time were investigated. The surface morphology of the fibers was evaluated by SEM. To determine the nitrate and phosphate adsorption on the modified fibers, UV-VIS spectrophotometer was used. Fiber samples modified under optimized conditions showed a high ability to adsorb nitrate and phosphate ions from aqueous media. Keywords: polypropylene, Ion adsorption, Plasma treatment, nitrate, phosphate, acrylic acid

In order to assess in vitro biomechanical behaviour of dental implants, numerous experimental methods can be used. In our experiment, we use dental implants inserted into the artificial jaws, made of ABS plastic material and Araldite D, and we chose the VIC method (Video Image Correlation), spatial version (3D), to monitor the deformation field of area surrounding implant. For both experiment types, with ABS mandible or Araldite D sheet, the results were similar and controllable. Authors are confident with this technique and hope that experimental methods will serve as a database for research in this area. Keywords: dental implants, biomechanics, ABS, Araldite D

Hybrid inorganic/organic films composed of an polyoxometalate (POM) (iron(III)-trisubstituted Keggin polyoxomolybdates, PFe3Mo9) and a non-conducting polymer [(poly(ortho-phenylenediamine)) or a conducting polymer (poly(1,8-diaminonaphtalene)) were synthesized by electropolymerization from aqueous solution on the surface of a graphite electrodes. Cyclic voltammetry gave evidence of a redox behaviour of the PFe3Mo9, irrespective of the type of polymer used for POM immobilization into the composite matrix. Keywords: polyoxometalate, electropolymerization, hydrogen peroxide, glucose

Renal parenchyma is served by a complex vascular-ductal system formed by renal artery (RA), renal vein (RV) and the pyelocaliceal system (PCS) continued by ureter. In the training of medical students and residents, the study of the interrelations of the elements of intraparenchymatous branches of the RA, RV tributaries, and PCS, as well as the analysis of renal corrosion casts is superior because it allows simultaneous analysis of the three vascular-ductal systems of the kidney. The present study examines the most favourable order of plastic mass injection for obtain good quality renal corrosion casts. There were used 36 kidneys from 18 domestic pigs, divided into three groups, to whom the vascularductal elements were injected with plastic (Technovit 7143), with different order of injection: the first group - with injection in order: PCS, RV and RA; the second group - with injection in order: PCS, RA and RV; the third group - with injection in order: RA, RV and PCS. Most affected by vascular compression were the renal vein and its intraparenchymatous tributaries. The most favourable order of plastic mass injection for obtain good quality renal corrosion casts by ex-situ injection is: RA, RV and PCS. Keywords: corrosion casts, pig kidney; pyelocaliceal system; renal artery; renal vein; training