Impact of B2O3 and La2O3 addition on structural, mechanical and biological properties of hydroxyapatite

In this study, hydroxyapatite-B2O3-La2O3 composites (with ≤ 20 wt.% B2O3 and ≤ 2 wt.% La2O3) were synthesized via wet precipitation method and calcined at 1100 °C for 1 h. X-ray diffraction (XRD) analysis revealed the existence of the pure hydroxyapatite (HA) phase with high crystallinity. Characteristic absorption bands of HA were also observed in Fourier transform infrared spectra. Furthermore, scanning electron microscopy images demonstrated that the addition of B2O3 and La2O3 into HA enhanced the particle growth. Mechanical properties of the composites were studied by diametral tensile test and the results showed that incorporation of 10 wt.% B2O3 and 2 wt.% La2O3 led to a 39% increase in tensile strength (compared to the pure HA). In vitro cytocompatibility of HA-B2O3-La2O3 composites was investigated using Osteosarcoma Cell Lines (Saos-2). Incorporation of B2O3 and La2O3 into HA had no toxic effect towards the cells. Based on its tensile strength properties and biological response, composite of 88 wt.% HA, 10 wt.% B2O3 and 2 wt.% La2O3 was suggested as a promising composite for bone tissue engineering applications

Structural and morphological analysis of zinc incorporated non-stoichiometric hydroxyapatite nano powders

ABSTRACT In this study, Zn incorporated non-stoichiometric hydroxyapatite (nHAp) was synthesized via precipitation method and effect of the incorporation of Zn (fraction: 2, 4, 6 and 8 mol-%) on the microstructure of nHAp was studied by XRD, FTIR analysis and SEM-EDS techniques. The formation of nHAp was confirmed by XRD and FTIR those showed that no secondary phase was formed through the Zn incorporation. The SEM studies also revealed that particles were formed in nano-metric size (30-60 nm). It was found that crystallite and particle size of Zn incorporated nHAp gradually decreased up to 6 mol-%, and started to increase while the Zn fraction reached up to the 8 mol-% and hence the morphology of the aggregated products was also changed. It can be concluded that the incorporation of Zn cations cause to form nHAp phase. Furthermore, the nHAp microstructure has deviated from stoichiometric condition by incorporation of more Zn cations

Investigation of tensile strength of hydroxyapatite with various porosities by diametral strength test

WOS: 000255904100013It is appropriate to administer the diametral test to biomedical materials used in dental applications because stresses formed on dental implants are similar to those that formed in this test. To show this similarity, an experimental study of diametral strength testing of hydroxyapatite was performed. The influence of porosity on hydroxyapatite was investigated experimentally to determine how the diametral strength was affected. Hydroxyapatite was air sintered at 1100 degrees C for 1 h with porosities ranging from 1 to 32%. The results indicated that hydroxyapatite with improved densification had higher diametral strength values. X-ray diffraction analysis showed that sintered samples were pure hydroxyapatite

Microhardness evaluation of non enzymatically glycated bovine femur cortical bone

Purpose: The aim of this study is to investigate deterioration in mechanical integrity of the collagen network of bovine bone formed by non-enzymatic glycation (NEG), a process that mimics aging by microindentation technique. Methods: Young and old bovine cortical bone specimens were rested in solutions for four weeks for the process of NEG and were grouped as ribosylated and non-ribosylated. A series of indentations were made on bone specimens weekly for each of 3-masses of 50 g, 100 g and 200 g for 10 s to detect the effect of indentation load and for each of five durations of 5 s, 10 s, 20 s, 30 s for 100 g to study the effect of indentation duration. The applied load was increased to 300 g, 500 g, 1000 g and 2000 g for 10 s to be able to make microcracks. Specimens were tested in the wet and dry state to study the effects of hydration on microhardness measurement. Results: Loads of 50 g, 100 g and 200 g for 10 s were able to differ ribosylated bone from non-ribosylated bone for the young and old bovine bones. Microhardness values increased with increasing incubation period. Microhardness of dry specimens were found to be statistically higher than that of wet specimens. Presence of extrinsic toughening mechanisms including crack bridging due to uncracked ligaments and collagen fibers were directly observed by scanning electron microscope (SEM). Ribosylated bone was found to have lower number of collagen bridging compared to non-ribosylated bovine bone. Conclusion: Microhardness test by these are able to discriminate non-modified collagen structure from modified collagen. On the other hand, it is found that microindentation was not able to discriminate the degree of NEG. © 2015 World Scientific Publishing Company

STRUCTURAL INVESTIGATION OF NANO HYDROXYAPATITES DOPED WITH Mg(2+) AND F(-) IONS

Pure and Mg(2+) & F(-) doped nano hydroxyapatites (HA) were synthesized by a precipitation method and sintered at 1100 degrees C to investigate their densification and structure. Different amounts of Mg(2+) and F ions were doped in to HAs. X-ray diffraction was used to identify the presence of phases And lattice parameters of HA and tri-calcium phosphates (TCP) present in the samples. Densification of HA was improved by the addition of these ions. In most of the doped samples, beta-tri-calcium phosphate (TCP) formation was observed as a second phase with the addition of Mg. Structure of the pure and doped samples were hexagonal and rhombohedral for HA and TCP, respectively

Effect of storage time on mechanical properties of extended-pour irreversible hydrocolloid impression materials

Statement of problem: Recent commercial extended-pour irreversible hydrocolloid impression materials (EPIHIMs) claim to maintain dimensional stability up to 120 hours. However, data regarding their mechanical properties and performance after 120 hours of storage are lacking. Purpose: The purpose of this in vitro study was to test the elastic recovery, strain in compression, and tear strength properties of 5 commercially available EPIHIMs, immediately after preparation and after 120 hours of storage under specific storage conditions. Material and methods: A total of 150 specimens were prepared in accordance with the ISO 21563:2013 standard from 5 commercially available EPIHIMs (Blueprint Xcreme, Kromopan, Alginmax, Hydrogum 5, and Alginelle). The specimens were subjected to elastic recovery, strain in compression, and tear strength tests immediately after specimen preparation (n=5) and after 120 hours of storage inside clear plastic zipper bags held at 23 °C (n=5). Data were analyzed with a multivariate analysis of variance (MANOVA) test for brand and duration parameters. Normality of data was analyzed with the Shapiro-Wilk test. The Duncan test or Games-Howell test was used for multiple comparisons (?=.05). Results: Elastic recovery and strain in compression values of the EPIHIMs tested were affected by brand and duration parameters (P.05). Data distribution was normal except for Alginmax in terms of the elastic recovery values and Blueprint Xcreme in terms of the strain in compression values (P.05). However, 120 hours of storage led both to a statistically significant decrease in mean strain in compression values of the tested EPIHIMs (P.05) and a statistically significant difference among mean strain in compression values of the tested EPIHIM brands (P.05). However, statistically significant differences were present among mean tear strength values of the tested EPIHIM brands tested immediately after preparation (P<.001) and after 120 hours of storage (P<.001). Conclusions: Despite variations in elastic recovery, strain in compression, and tear strength properties of the EPIHIMs tested, all the materials fulfilled the requirements to comply with the ISO 21563:2013 standard even after 120 hours of storage. © 2019 Editorial Council for the Journal of Prosthetic DentistryTürkiye Bilimsel ve Teknolojik Araştirma Kurumu Türkiye Bilimsel ve Teknolojik Araştirma Kurumu: 215M056This study was financially supported by T?rkiye Bilimsel ve Teknolojik Ara?t?rma Kurumu (The Scientific and Technological Research Council of Turkey) with the project #215M056

A review of synthesis methods, properties and use of monetite cements as filler for bone defects

The major objective of the current review is to highlight the prime importance of bone cements particularly monetite cement as filler to treat various bone defects which may result due to osteoporosis, some accidents, some trauma disease or any other orthopedic surgical disorders. Previous studies showed that polymethyl methacrylate (PMMA), calcium phosphate cements (CPCs), dicalcium phosphate (DCP) cement and acrylic polymer cements have been employed to improve the bone defects, but these materials have a certain issue of insitu setting. To overcome these problems, concentration was swiftly diverted towards monetite cement which revealed better results. Therefore, in this review, more focus has been given to the monetite cement. In this work, a brief but very productive discussion has also been inducted about the various synthetic routes to synthesize monetite cement and its properties which will help the readers to get key information about the growing significance of monetite cement as a bone filler and its future use and importance. The main theme of this review is to highlight the tremendous achievements achieved in the monetite cementing materials and their further scope in the near future as to upgrade their properties and use in the biomedical field

Diametral strength testing of hydroxyapatites doped with yttrium and fluoride

This study aimed to investigate the diametral strength testing of hydroxyapatite (HA) doped with Y and fluoride with different compositions. Hydroxyapatites were synthesised by precipitation method and sintered at 900, 1100 and 1300 degrees C for 1 h. High amounts of doping caused a decrease in relative densities of HAs. Higher sintering temperatures helped in increasing the relative densities. No second phases were observed by X-ray diffraction spectra of 2.5 mol.-%Y and 2.5 mol.-%F doped HA after the sintering at all temperatures. Trace amounts of beta-tricalcium phosphate was found in 7.5 mol.-%Y and 2.5 mol.-%F doped HA sintered at 1100 and 1300 degrees C. Diametral strength of doped HAs mostly enhanced with the addition of Y3+ and F- . 2.5YFHA sintered at 1300 degrees C had the highest diametral strength of 11.6 MPa with a relative density of 94.3% of theoretical density

Mesoporous strontium doped nano sized sulphate hydroxyapatite as a novel biomaterial for bone tissue applications

In this study a novel nano-structured hydroxyapatite (HA) incorporated with different fractions of Sr2+ and SO42− ions has been synthesized using the wet precipitation method and characterized.</p