Fluoride is one of the elements commonly present in the human environment. Due to its characteristics, it is very widely used in medicine, dentistry, industry or agriculture. On the other hand, its universality possesses a real threat to the human body in the form of acute and chronic poisoning. The aim of this paper is to characterize the properties of fluoride and its effects on the human body, as well as the sources of its occurrence. Particular emphasis is placed on the safety of its use and optimal dosage intake, which prevents accumulation and reduces its potential side effects. The positive effect of proper fluoride supply is widely described. In order to avoid overdose, it is best to consult a specialist to properly select the dosage.

Modular tissue engineering (MTE) is a novel “bottom-up” approach to create engineered biological tissues from microscale repeating units. Our aim was to obtain microtissue constructs, based on polymer microspheres (MSs) populated with cells, which can be further assembled into larger tissue blocks and used in bone MTE. Poly(L-lactide-co-glycolide) MS of 165 ± 47 µm in diameter were produced by oil-in-water emulsification and treated with 0.1 M NaOH. To improve cell adhesion, MSs were coated with poly-L-lysine (PLL) or human recombinant collagen type I (COL). The presence of oxygenated functionalities and PLL/COL coating on MS was confirmed by X-ray photoelectron spectroscopy (XPS). To assess the influence of medium composition on adhesion, proliferation, and osteogenic differentiation, preosteoblast MC3T3-E1 cells were cultured on MS in minimal essential medium (MEM) and osteogenic differentiation medium (OSG). Moreover, to assess the potential osteoblast–osteoclast cross-talk phenomenon and the influence of signaling molecules released by osteoclasts on osteoblast cell culture, a medium obtained from osteoclast culture (OSC) was also used. To impel the cells to adhere and grow on the MS, anti-adhesive cell culture plates were utilized. The results show that MS coated with PLL and COL significantly favor the adhesion and growth of MC3T3-E1 cells on days 1 and 7, respectively, in all experimental conditions tested. On day 7, three-dimensional MS/cell/extracellular matrix constructs were created owing to auto-assembly. The cells grown in such constructs exhibited high activity of early osteogenic differentiation marker, namely, alkaline phosphatase. Superior cell growth on PLL- and COL-coated MS on day 14 was observed in the OSG medium. Interestingly, deposition of extracellular matrix and its mineralization was particularly enhanced on COL-coated MS in OSG medium on day 14. In our study, we developed a method of spontaneous formation of organoid-like MS-based cell/ECM constructs with a few millimeters in size. Such constructs may be regarded as building blocks in bone MTE.

Introduction. Acrylic resin is a basic material used in preparation of partial and complete dentures. One of the methods of improving mechanical properties of removable dentures is reinforcing acrylic resin with artificial fibers. Aim of the study. To compare mechanical properties of acrylic material reinforced with various types of glass fibers. Material and method. Heat-cured Estetic acrylic resin by Wiedent was used for denture bases. Glass mat, fiberglass fabric, long glass fibers and short glass fibers were used as reinforcing phase of the acrylic resin. In total, forty specimens were prepared, of which eight samples were controls. Research samples consisted of four groups of eight specimens each. Mechanical examinations in three-point bending test were conducted by means of the Zwick 1435 universal testing machine. Results. Specimens reinforced with short glass fibers achieved the highest values of maximum bending force (105.7 ± 8.9 N). It corresponded to the highest values of bending strength (126.8 ± 10.7 MPa). The lowest strength was found for specimens reinforced with glass mat (82.8 ± 11.8 MPa). The highest value of Young’s modulus was obtained for the samples reinforced with fiberglass fabric (3.7 ± 0.8 GPa). The highest values of deflection at maximum bending force were found for the samples reinforced with long glass fibers (4.0 ± 0.6 mm). Conclusions. The highest bending strength parameters were found for specimens reinforced with short and long glass fibers. Short glass fibers are better at improving mechanical properties of acrylic resin than long glass fibers.

A novel way of obtaining highly porous cements is foaming them with the use of nonionic surface active agents (surfactants).