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Removable partial dentures (PDs) are an affordable and effective treatment option in patients with partial edentations.This aim of this study is to evaluate the differences, in the terms of patient’s compliance, in restoration of partial edentations through three types of PDs, achieved of Meliodent-Kulzer acrylic resin, Valplast® polyamide resin, respectively of BioDentaplast-Bredent acetal resin. Investigations were carried out on 78 patients (3 groups of 26 patients), to which were performed 101 PDs (35 of Meliodent-Kulzer, 33 of polyamide Valplast®, respectively 33 of BioDentaplast-Bredent) and after the accommodation period with the dentures, six assays of compliance have been conducted. The results of the research have demonstrated that PDs made of flexible materials were far more favourable than those made of Meliodent acrylic resin, and PDs with BioDentaplast framework presented the best impact. The ascertained differences are relevant in the treatment of partial edentation, for choice of the best option for one of these three polymeric denture base materials.

This paper presents the results of the research work performed by the authors aiming at highlighting and quantifying the reinforcement effects (restoring of the mechanical strength) on transmission pipelines, generated by applying composite material sleeves in the areas in which the steel pipes of these lines have local surface defects (metal loss – like flaws). The models proposed to that purpose have been confirmed by performing some experimental programs, the first one consisting of the examination of the behaviour of some full-scale steel pipe specimens, with metal loss – like flaws (made by machining), on which reinforcing wraps made of composite material have been applied (with polymeric matrix and fiberglass fabric), subjected to internal pressure loading, up to bursting, and the second one aiming at the determination of the state of stress and strain in the pipelines on which reinforcing wraps made of composite material have been applied and which are subjected to internal pressure loading, in the elastic range. The items discussed and the results presented in the paper are mainly useful for the development and qualification of the composite materials repair systems for the transmission pipelines, according to the requirements of the standards ASME-PCC2 and ISO 24817.

The growing utilisation of carbon materials increases the waste generation. Therefore, the development of new composites using recycled carbon fiber reinforced polymer (rCFRP) within the present study was driven by environmental and economic factors. Six configurations of new polymeric matrix composites were developed and evaluated by mechanical tests (flexural, compression and interlaminar stress), microscopic and thermal analysis. Four configurations of composites were obtained by filling the matrix with rCFRP powder and fibrous elements mixture, the reinforcement phase being produced by grinding carbon fiber reinforced polymer (CFRP) waste. The new composite configurations showed an increase in mechanical properties with rising the reinforcement fraction. The samples analyzed by stereomicroscopy reveled a fairly homogeneous distribution of the reinforcement in the matrix for 5%wt. up to 30%wt., whereas thermal analysis showed no significant changes in the glass transition temperatures of developed materials. Two configurations of composites were obtained by chemical etching of the matrix and recovering carbon fiber woven, used subsequently as reinforcement phase for new composite configurations. The same method was used for determining the volume fraction of CFRP composite constituents. Initial results demonstrate that recycled carbon remains a highly satisfactory engineering material. These results showed that recycled FRP composites can be used to develop new less demanding composite materials or improve some properties of FRP composites.

The textile polymeric composites define a class of advanced materials, utilising fabrics as reinforcement. The geometry, as well as the structure of textile reinforced polymeric composites, are much more complex than that of composites reinforced with unidirectional fibres. The mechanical properties of textile reinforced composites are influenced by several parameters such as fibre material, the internal geometry of the fabric, number of counts, size of gap between adjacent yarns, height of woven layer, undulation and thickness of the composite lamina. Each of these factors can influence the structural behaviour and can be modelled based on its specific length scale. This paper is focused on the modelling procedures of the in-plane stiffness characteristics, specific to satin reinforced laminated composites. The method used is a compromise between the continuous and pure discrete approaches and it is associated with a mesoscopic analysis of the repetitive unit cell (RUC). The elastic properties of the textile reinforced polyester composite, using S glass fibre, arranged in satin reinforcement, are determined and analysed taking into account the variation of two characteristic geometric parameters, namely the width and the height of the reinforcing tow.

This paper reports the fabrication of spherical particles developed as bone tissue regenerative biomaterials. Inspired by the extracellular matrix of hard tissues, the particles were generated through the mineral loading of a macromolecular matrix consisting in a bicomponent hydrogel (interpenetrated polymer networks based on gelatin and alginate). The study describes the effects of the peptide-polysaccharide ratio on the morpho-structural features, water affinity, and interaction with MG-63 osteoblast-like cells.

The management of laryngeal trauma represents one of the most challenging problems for an ENT surgeon. The alternatives vary from a “wait and see” approach to extensive and immediate reconstructive interventions, but in all cases the risk of laryngeal stenosis remains high. This translates into a poor quality of life for the patients and increased costs for the health system. The use of a resorbable plate for the reconstruction of the affected cricoid has the advantages of requiring a single intervention and enabling the patient to return to his normal activities in a shorter period of time. It is why we present this method of approach, which can be a viable alternative in managing these difficult cases.

The aim of this study was to point out the effect of elaboration parameters on the structure and electrochemical stability of a bioinspired hybrid film chitosan with hydroxiapatite (HAp) on Ti50%Zr alloy. The new hybrid films based on chitosan and hydroxiapatite were elaborated electrochemically using various ratio between components and different temperature and time of electrodeposition. The electrodeposition electrolye was a mixture of (NH4)2HPO4 , Ca(NO3)2 and chitosan. The structure was identified by Fourier transform infrared (FTIR) spectroscopy, and the morphology associated with elemental analysis were evaluated by scanning electronic microscopy (SEM) and X ray diffraction. Surface characterization was completed with contact angle measurements. Electrochemical tests in physiological solution (NaCl 0.9%) potentiodinamic polarization curves (tafel plots procedures). Based on experimental data we can conclude that the hybrid coating with higher HAp concentration is the most stable.

Mixed mode four-point testing is performed on polyurethane foams. This paper presents only the results on the stress intensity factors (SIFs) obtained experimentally for a density of 325 kg/m3, although tests were done for three foam densities. An asymmetric four-point bending setup was used for determining the critical SIFs in Mode I and Mode II, and discussions on the influence of the initial crack length on the SIF values are done. As initial crack length is increased the theoretical predictions give a better comparison to experimentally obtained results.

Composite materials based on synthetic leathers from Polyvinyl Chloride and Polyurethane with knitted fabric support are increasingly used in many sectors of industry. Two synthetic leathers have been analysed both through experimental and analytical methods in order to evaluate their elastic properties. The analytical evaluation of material elasticity was conducted based on a micromechanical approach, taking into account the Krenchel’s coefficient for Polyester fibre orientation and based on the analytical models of Leaf and Glaskin and Chamis. Experimental data was gathered using microscopic analysis and the mechanical impulse excitation test method. Results showed a good correlation with that from the experimental study. Thus, it was confirmed that the Leaf and Glaskin model and the Chamis model have a good accuracy in prediction of fibres orientation and respectively elastic properties of synthetic leather based on plain jersey.

Various techniques have been proposed for the fabrication of surgical guide templates in orthodontics. The objective of this paper is to review the associated literature and recent advancements in this field, based on design concept , materials and technique.