Structural characterization and dielectrical properties of Ag-doped nano-strontium apatite particles produced by hydrothermal method

The Effect of Doping on the Electrical and Dielectric Properties of Hydroxyapatite for Medical Applications: From Powders to Thin Films

Recently, the favorable electrical properties of biomaterials have been acknowledged as crucial for various medical applications, including both bone healing and growth processes. This review will specifically concentrate on calcium phosphate (CaP)-based bioceramics, with a notable emphasis on hydroxyapatite (HA), among the diverse range of synthetic biomaterials. HA is currently the subject of extensive research in the medical field, particularly in dentistry and orthopedics. The existing literature encompasses numerous studies exploring the physical-chemical, mechanical, and biological properties of HA-based materials produced in various forms (i.e., powders, pellets, and/or thin films) using various physical and chemical vapor deposition techniques. In comparison, there is a relative scarcity of research on the electrical and dielectric properties of HA, which have been demonstrated to be essential for understanding dipole polarization and surface charge. It is noteworthy that these electrical and dielectric properties also offer valuable insights into the structure and functioning of biological tissues and cells. In this respect, electrical impedance studies on living tissues have been performed to assess the condition of cell membranes and estimate cell shape and size. The need to fill the gap and correlate the physical-chemical, mechanical, and biological characteristics with the electrical and dielectric properties could represent a step forward in providing new avenues for the development of the next-generation of high-performance HA-doped biomaterials for future top medical applications. Therefore, this review focuses on the electrical and dielectric properties of HA-based biomaterials, covering a range from powders and pellets to thin films, with a particular emphasis on the impact of the various dopants used. Therefore, it will be revealed that each dopant possesses unique properties capable of enhancing the overall characteristics of the produced structures. Considering that the electrical and dielectric properties of HA-based biomaterials have not been extensively explored thus far, the aim of this review is to compile and thoroughly discuss the latest research findings in the field, with special attention given to biomedical applications.

Microstructural, biocompatibility and mechanical investigation of MgHAp and AgHAp: Comparative report

It is imperative to investigate the effect of addition of different size metallic ions in HAp and study the changes in biocompatibility and mechanical properties. Silver and magnesium ions are two vital ions needed in our body. Silver ions are known to inhibit the microbes, while magnesium ions are known to increase the mechanical properties. The present study reports the comparative properties of MgHAp and AgHAp synthesised by sol-gel wet chemical method. Changes in the morphology, phase analysis, corrosion resistance, dielectric properties, hardness and the thrombus behaviour of HAp doped Ag and Mg ions has been investigated. In this work, we have presented a comparative study of both the metal doped ionsto find which of the ions and which weight percent of the ions can be best suited to be incorporated into the HAp matrix for hard tissue implants. All wt% AgHAp showed the better corrosion resistance than all the MgHAp samples. However, MgHAp showed higher value of hardness in comparison to AgHAp samples. The mechanical strength was found to increase with the increase in Mg wt% in MgHAp but for AgHAp the hardness value decreased with increase in the concentration. The impedance and dielectric loss decreased with increasing frequency for both the samples. Both the ion doped hydroxyapatite showed moderate clotting behaviour as compared to pure HAp. But 2 wt% MgHAp and 4 wt% AgHAp showed better thrombogenic behaviour. It is imperative to investigate the effect of addition of different size metallic ions in HAp and study the changes in biocompatibility and mechanical properties. Silver and magnesium ions are two vital ions needed in our body. Silver ions are known to inhibit the microbes, while magnesium ions are known to increase the mechanical properties. The present study reports the comparative properties of MgHAp and AgHAp synthesised by sol-gel wet chemical method. Changes in the morphology, phase analysis, corrosion resistance, dielectric properties, hardness and the thrombus behaviour of HAp doped Ag and Mg ions has been investigated. In this work we have presented a comparative study of both the metal doped ions to find which of the ions and which weight percent of the ions can be best suited to be incorporated into the HAp matrix for hard tissue implants. All wt% AgHAp showed the better corrosion resistance than all the MgHAp samples. However, MgHAp showed higher value of hardness in comparison to AgHAp samples. The mechanical strength was found to increase with the increase in Mg wt% in MgHAp but for AgHAp the hardness value decreased with increase in the concentration. The impedance and dielectric loss decreased with increasing frequency for both the samples. Both the ion doped hydroxyapatite showed moderate clotting behaviour as compared to pure HAp. But 2 wt% MgHAp and 4 wt% AgHAp showed better thrombogenic behaviour.

In Vivo Evaluation of the Effects of B-Doped Strontium Apatite Nanoparticles Produced by Hydrothermal Method on Bone Repair

In the present study, the structural, morphological, and in vivo biocompatibility of un-doped and boron (B)-doped strontium apatite (SrAp) nanoparticles were investigated. Biomaterials were fabricated using the hydrothermal process. The structural and morphological characterizations of the fabricated nanoparticles were performed by XRD, FT-IR, FE-SEM, and EDX. Their biocompatibility was investigated by placing them in defects in rat tibiae in vivo. The un-doped and B-doped SrAp nanoparticles were successfully fabricated. The produced nanoparticles were in the shape of nano-rods, and the dimensions of the nano-rods decreased as the B ratio increased. It was observed that the structural and morphological properties of strontium apatite nanoparticles were affected by the contribution of B. A stoichiometric Sr/P ratio of 1.67 was reached in the 5% B-doped sample (1.68). The average crystallite sizes were 34.94 nm, 39.70 nm, 44.93 nm, and 48.23 nm in un-doped, 1% B-doped, 5% B-doped, and 10% B-doped samples, respectively. The results of the in vivo experiment revealed that the new bone formation and osteoblast density were higher in the groups with SrAp nanoparticles doped with different concentrations of B than in the control group, in which the open defects were untreated. It was observed that this biocompatibility and the new bone formation were especially elevated in the B groups, which added high levels of strontium were added. The osteoblast density was higher in the group in which the strontium element was placed in the opened bone defect compared with the control group. However, although new bone formation was slightly higher in the strontium group than in the control group, the difference was not statistically significant. Furthermore, the strontium group had the highest amount of fibrotic tissue formation. The produced nanoparticles can be used in dental and orthopedic applications as biomaterials.

Vibrational Imaging Techniques for the Characterization of Hard Dental Tissues: From Bench-Top to Chair-Side

Currently, various analytical techniques, including scanning electron microscopy, X-Ray diffraction, microcomputed tomography, and energy dispersive X-ray spectroscopy, are available to study the structural or elemental features of hard dental tissues. In contrast to these approaches, Raman Microspectroscopy (RMS) has the great advantage of simultaneously providing, at the same time and on the same sample, a morpho-chemical correlation between the microscopic information from the visual analysis of the sample and its chemical and macromolecular composition. Hence, RMS represents an innovative and non-invasive technique to study both inorganic and organic teeth components in vitro. The aim of this narrative review is to shed new light on the applicative potential of Raman Microspectroscopy in the dental field. Specific Raman markers representative of sound and pathological hard dental tissues will be discussed, and the future diagnostic application of this technique will be outlined. The objective and detailed information provided by this technique in terms of the structure and chemical/macromolecular components of sound and pathological hard dental tissues could be useful for improving knowledge of several dental pathologies. Scientific articles regarding RMS studies of human hard dental tissues were retrieved from the principal databases by following specific inclusion and exclusion criteria.

Selected Spectroscopic Techniques for Surface Analysis of Dental Materials: A Narrative Review

The presented work focuses on the application of spectroscopic methods, such as Infrared Spectroscopy (IR), Fourier Transform Infrared Spectroscopy (FT-IR), Raman spectroscopy, Ultraviolet and Visible Spectroscopy (UV-Vis), X-ray spectroscopy, and Mass Spectrometry (MS), which are widely employed in the investigation of the surface properties of dental materials. Examples of the research of materials used as tooth fillings, surface preparation in dental prosthetics, cavity preparation methods and fractographic studies of dental implants are also presented. The cited studies show that the above techniques can be valuable tools as they are expanding the research capabilities of materials used in dentistry.