The novelty of this study consists in the formulation and characterization of three experimental dental composites (PM, P14M, P2S) for cervical dental lesion restoration compared to the commercial composites Enamel plus HRi® - En (Micerium S.p.A, Avengo, Ge, Italy), G-ænial Anterior® - Ge, (GC Europe N.V., Leuven, Belgium), Charisma® - Ch (Heraeus Kulzer, Berkshire, UK). The physio-chemical properties were studied, like the degree of conversion and the residual monomers in cured samples using FTIR-ATR (attenuated total reflectance) and HPLC-UV (ultraviolet detection), as well as the evaluation of the mechanical properties of the materials. The null hypothesis was that there would be no differences between experimental and commercial resin composites regarding the evaluated parameters. Statistical analysis revealed that water and saliva storage induced significant modifications of all mechanical parameters after three months for all tested materials, except for a few comparisons for each type of material. Storage medium seemed not to alter the values of mechanical parameters in comparison with the initial ones for: diametral tensile strength (DTS-saliva for Ge and PM, compressive strength (CS)-water for Ch, DTS-water and Young’s modulus YM-saliva for P14M and YM-water/ saliva for P2S (p > 0.05). Two of the experimental materials showed less than 1% residual monomers, which sustains good polymerization efficiency. Experimental resin composites have good mechanical properties, which makes them recommendable for the successful use in load-bearing surfaces of posterior teeth.

Magnesium alloys as bioresorbable materials with good biocompatibility have raised a growing interest in the past years in temporary implant manufacturing, as they offer a steady resorption rate and optimal healing in the body. Magnesium exhibits tensile strength properties similar to those of natural bone, which determines its application in load-bearing mechanical medical devices. In this paper, we investigated the biodegradation rate of Mg-Zn-Mn biodegradable alloys (ZMX410 and ZM21) before and after coating them with hydroxyapatite (HAP) via the electrophoretic deposition method. The experimental samples were subjected to corrosion tests to observe the effect of HAP deposition on corrosion resistance and, implicitly, the rate of biodegradation of these in simulated environments. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) provided detailed information on the quality, structure, and morphology of the HAP coating. The obtained results demonstrate that coating of Mg-Zn-Mn alloys by HAP led to the improvement of corrosion resistance in simulated environments, and that the HAP coating could be used in order to control the biodegradation rate.

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Sixteen working welders with more than seven years' exposure and a chest radiograph suggestive of siderosis and I3 healthy unexposed men were studied. Each subject had a comprehensive medical and work history, physical examination, standard chest film, and pulmonary function investigation (lung volumes, ventilatory capacities, pulmonary compliance in static and dynamic conditions, specific compliance, and elastic work of breathing).Seven of the welders had some exertional dyspnoea and three complained of cough. Although spirographic values were generally within the normal range, the arc welders had a statistically significant reduction in static and functional compliance. Seven had a functional compliance under the lower limit of the control group. Differences in elastic work of breathing and specific compliance were not significant.The possible causes of pulmonary function impairment in welders are discussed.Since I936, when Doig and McLaughlin reported their first cases, several studies have been devoted to the clinical, epidemiological, roentgenological, and functional aspects of welders' siderosis.Most authors are agreed in considering this condition as harmless, with no impairment of the general health or respiratory function (Collen, I947; Doig and Duguid, ig5i; Doig and Challen, I964; Enzer and Sander, I938; Sander, I944). However, some recent papers have questioned this view (Charr, I955, I956; Friede and Rachow, I96I; Kierst, Uselis, Graczyk, and Krynicki, I964; Sevcik, Chalupa, Klhufkova, and Hrazdira, I960).The purpose of the present work is to examine some aspects of pulmonary ventilation in welders at work and to assess the possible impairment of pulmonary elasticity. Material and MethodsFifty-two subjects were picked at random from the 70 welders of a metallurgical plant. Sixteen were then selected as having over seven years' exposure as arc welders and chest radiographs suggestive of siderosis. The International Labour Office (1959) criteria for evaluation of chest films were used. All subjects had a complete medical and work history, clinical examination, and standard chest postero-anterior film. Individuals with chronic cardiopulmonary disease or acute respiratory illness during the last six months period were excluded.These i6 welders were compared with a control group of 13 normal individuals with no dust exposure. The ages and heights of subjects are presented in Table I. No significant differences in height, age, or smoking habits were found between the groups. The average duration of exposure was I7-I years (range 7 to 30 years).Lung function tests comprised determinations of lung volumes, forced expiratory volumes, helium-mixing time, and pulmonary mechanics. All determinations were carried out on fasting subjects in a sitting position.

The developement and regeneration of healthy bone tissue is a complex process that includes the interaction of different cell types and requires a set of coordinated processes. The loss of bone tissue may occur due to various reasons: surgical removal, bone trauma (i.e., fractures) or systemic bone loss (i.e., osteoporosis). When the natural bone tissue is destroyed, the regeneration capacity of the bone is not always satisfactory. The result consists therefore in many functional and structural aberrations. In order to improve and accelerate the healing process, bone substitutes have been developed. Hydroxyapatite has been widely used in bone applications due to its excellent biocompatibility, osteoconductivity and bioactivity [1,2]. The objective of this research is to obtain a new composite biomaterial that can be used as bone substitute. In this study, bovine hydroxyapatite obtained from freshly calcined bovine femur was used. The objective of this research is to obtain a new composite biomaterial that can be used as bone substitute. The experimental composite samples were obtained using bovine hydroxyapatite as matrix and tricalcium phosphate, respectively, magnesium oxide as reinforcement materials. The synthesis process of these new biomaterial composites, the effect of chemical composition, surface structure, chemical and phase composition as well as mechanical features have been investigated.