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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

This paper presents our experiments on obtaining and characterizing polymeric composites based on wood sawdust and natural rubber. Natural rubber was crosslinked both through a classic method – using benzoyl peroxide at high temperature, and an unconventional method at room temperature – electron beam irradiation. Physico-mechanical properties such as hardness, modulus at 100% elongation and tensile strength indicate a significant improvement as a result of adding wood sawdust to blends. Better results have been obtained using crosslinking by electron beam irradiation. The crosslinking rates of samples, measured using the Flory-Rehner equation increase as the amount of wood sawdust in blends increases and as the electron beam irradiation dose increases. The swelling parameters of samples significantly depend on the amount of wood sawdust in blends, because the latter has hydrophilic characteristics. Key-words: natural rubber, wood sawdust, irradiation, physico–mechanical characteristics, crosslink density, swelling parameters

The bond strength of the root canal sealers to dentin and core material seems to be a very important property for maintaining the integrity and the seal of root canal filling. This in vitro study aimed to evaluate and compare the bond strength of three different root canal sealers. Forty five extracted single-root human teeth were prepared using ProTaper system. Teeth were divided into three groups (n=15) for obturation using AH Plus, RealSeal and a new, experimental endodontic sealer containing hydroxyapatite. Each tooth was obturated using warm vertical condensation technique in the apical third and gutta-percha injection in the middle and coronal thirds of the root canal. All teeth were sectioned transversally at the apical and middle thirds into 1 mm thick discs. Push-out tests were performed using a universal mechanical testing machine (Lloyd Instruments – LR5k plus). The maximum load at failure was recorded and divided by the area to obtain the bond strength in MPa. Using a stereomicroscope (STEMI 2000 C Zeiss, Jena, Germany), at a magnification of 20x, the interface where the obturation failure occurred was identified. Statistical analysis was performed and the result showed non significant differences between the three endodontic sealers at each level obturation. Also, the stereomicroscopic analysis showed a good adhesion to dentin for all sealers. The experimental sealer adhesion is comparable to that of the two consecrated materials. Keywords: push-out test, bond strength, endodontic sealer, root canal obturation

Profiled steel sheeting dry board (PSSDB) consists of steel sheeting that are connected to a dry board using self-drilling and self-tapping screw to form a light composite structure. This study focuses on PSSDB that uses 12 M geopolymer concrete infill with half-sized dry-board infill (GPCHB). The detected weakness of the profiled steel sheeting on this PSSDB system is due to the relatively easy occurrence of local buckling on its structure as it reaches an ultimate load, especially on the top flange. This study aims to analyze the relationship between stiffness and deflection at the mid-span of PSSDB systems using different parameters. Results show that the panel with 12 M GPCHB has 107% and 40% increase in rigidity compared with those of the control (without infill) and full board normal concrete panels, respectively. Mid-span deflection is also reduced to 52%. In conclusion, stiffness increases and deflection decreases when 12 M GPCHB is used in the panel. Keywords: composite structure, geopolymer concrete, weakness, local buckling, stiffness