Bone regeneration has gained attention in the biomedical field, which has led to the development of materials and synthesis methods meant to improve osseointegration and cellular bone activity. The properties of hydroxyapatite, a type of calcium phosphate, have been researched to determine its advantages for bone tissue engineering, particularly its biocompatibility and ability to interact with bone cells. Recently, the advantages of utilizing nanomolecules of hydroxyapatite, combined with various substances, in order to enhance and combine their characteristics, have been reported in the literature. This review will outline the cellular and molecular roles of hydroxypatite, its interactions with bone cells, and its nano-combinations with various ions and natural products and their effects on bone growth, development, and bone repair.

Surface enhanced Raman spectroscopy (SERS) represents a promising technique in providing specific molecular information that could have a major impact in biomedical applications, such as early cancer detection. SERS requires the presence of a suitable plasmonic substrate that can generate enhanced and reproducible diagnostic relevant spectra. In this paper, we propose a new approach for the synthesis of such a substrate, by using concentrated silver nanoparticles purified using the Tangential Flow Filtration method. The capacity of our substrates to generate reproducible and enhanced Raman signals, in a manner that can allow cancer detection by means of Multivariate Analysis (MVA) of Surface Enhanced Raman (SER) spectra, has been tested on blood plasma samples collected from 35 healthy donors and 29 breast cancer patients. All the spectra were analyzed by a combined Principal Component-Linear Discriminant Analysis. Our results facilitated the discrimination between healthy donors and breast cancer patients with 90% sensitivity, 89% specificity and 89% accuracy. This is a direct consequence of substrates’ ability to generate diagnostic relevant spectral information by performing SERS measurements on pristine blood plasma samples. Our results suggest that this type of solid substrate could be employed for the detection of other types of cancer or other diseases by means of MVA-SERS procedure.

Biological effects of low-dose ionizing radiation (IR) have been unclear until now. Saliva, because of the ease of collection, could be valuable in studying low-dose IR effects by means of surface-enhanced Raman spectroscopy (SERS). The objective of our study was to compare the salivary SER spectra recorded before and after low-dose IR exposure in the case of pediatric patients (PP). Unstimulated saliva was collected from ten PP before and after irradiation with a cone beam computed tomography (CBCT) machine used for diagnostic purposes. The SERS measurements have been recorded on dried saliva samples using a solid nanosilver plasmonic substrate synthesized using an original method developed in our laboratory. The experimental results showed that salivary SER spectra are dominated by three vibrational bands (441,735 and 2107 cm⁻¹) that can be assigned to bending and stretching vibrations of salivary thiocyanate (SCN-). After exposure, an immediate increase of vibrational bands assigned to SCN- has been recorded in the case of all samples, probably as a result of IR interaction with oral cavity. This finding suggests that SCN- could be used as a valuable biomarker for the detection and identification of low-dose radiation effects.

(1) Background: Natural-looking dental restorations require careful selection of the restorative material, with color and translucency characteristics similar to the natural dental structures. (2) Objectives: This research aimed to evaluate if there is compatibility regarding the color and translucency between different commercial RBCs in different layering recipes. (3) Methods: Sixty 1 mm thick disk specimens were produced from three different RBCs: ESS (Essentia-GC), BEG (Brilliant Ever Glow-Coltene), and IPS (IPS Empress Direct-Ivoclar Vivadent). Three different opacities and translucencies (enamel, dentin, and opaque shades) from each system were used in four recipes (R1-enamel, R2-dentin, R3-enamel and dentin, R4-enamel, dentin, and opaque) to obtain single-, double-, and triple-layered samples, respecting the anatomical layering technique. CIE L*, a*, b*, C*, h⁰ coordinates were recorded, and the relative translucency parameter (RTP₀₀) was calculated. Further, the color differences (ΔE₀₀) and the difference in translucencies ΔRTP₀₀ were analyzed between the materials and between the layered recipes. (4) Results: The CIE L* and h° color coordinates and RTP₀₀ showed significant differences among all three RBCs for all four recipes (p < 0.001). The decreasing order of translucency for each recipe was R1: ESS > BEG > IPS, R2 and R3: BEG > IPS > ESS, R4: BEG > ESS > IPS. Important differences were found in color and translucency among the recipes for each of the three RBCs tested (p < 0.001). The decreasing order of translucency for the tested RBCs was ESS: R1 > R3 > R4 > R2, BEG and IPS: R1 > R3 > R2 > R4. (5) Conclusions: No significant compatibility was observed in color and translucency among different layering recipes of the same composite materials nor between similar layering recipes when using different composites. The color differences between materials were more significant than the differences in translucency for each recipe.