română FLORENTINA GRIGORE, MAGDALENA LUNGU, DORINEL TĂLPEANU, ALINA MELINESCU, GEORGETA VELCIU
Abstract
In this paper it is shown the obtaining of dense hydroxyapatite (HA) through the technology of sintering with spark plasma discharge (Spark Plasma Sintering-SPS). From hydroxyapatite powder obtained by the method of precipitation from solutions of salts have been sintered disc through the SPS to 1100°C, and 950°C for 5 minutes. In a conventional method of powder uniaxially pressing disks were obtained that were sintered at 950°C and 1100°C with landing 2 hours at final temperature. The samples obtained have been characterized by analysis of X-ray diffraction for the study of the composition and analysis of phases electronic microscopy (SEM) for revealing the microstructure. Samples of HA obtained by sintering the plasma discharge (SPS) ahead of those obtained by conventional process showed a dense structure with low porosity and physical-mechanical properties, improved hardness of at least 2.49 GPa and Young’s modulus of at least 65 GPa.
Keywords
biomaterials, dense hydroxyapatite, SPS, hardness
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Year
2015
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Issue
45 (2)
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Pages
155-159
GABRIELA PURCEL, ADRIAN SURDU, ŞTEFANIA STOLERIU
Abstract
Silicon nitride attracts the attention of many researchers for its use in orthopedic and dental applications, but is not yet established as a biomaterial, the research is ongoing. Present paper deals with the obtaining of Si3N4 ceramics unconventional heat treatment (spark plasma sintering.
The sintering process was pursued through the variation of four influencing parameters: sintering temperature, the heating rate, the pressure applied during sintering and soaking time. The obtained ceramics were characterized using X-ray diffraction for the phases determination and scanning electron microscopy for microstructure characterization. Also, were determined ceramic and mechanical properties.
By testing the biocompatibility of these ceramics in contact with the physiological environment by following the evolution of pH and ionic conductivity on immersion of ceramics in SBF is found that pH values and ionic conductivity samples varies widely in the first days but after stabilizes around SBF values.
Regarding the antibacterial effect, the tests indicate a triple value of biofilm inhibition area for the Si3N4 samples, as comparing with pure titanium, measured under the same condition. Also, was evaluated the MG-63 cell proliferation (by lactate dehydrogenase method - LDH) and morphology.
Keywords
Si3N4, spark plasma sintering, biocompatibility
MUSTAFA BASIM MOHAMMED AL TAMEEMI, DRAGOŞ GUDOVAN, RALUCA STAN, DAN MIHĂIESCU, CRISTINA OTT
Abstract
In this work it have been investigated the difference of the encapsulation efficiency and the release behavior of silica nanotubes and MCM-41 by using Ibuprofen as drug model. The highest encapsulation efficiency was in MCM-41, while the highest loaded Ibuprofen amount was in silica nanotubes. According to their larger size folded, silica nanotubes release percentage was around 80% which is higher than MCM-41 which was around 26%. It is worth mentioning that TEOS was used as silica precursor, and CTAB as a surfactant for the synthesis of both the nanostructured materials alike.
Keywords
MCM-41, silica nanotubes, Ibuprofen, Encapsulation efficiency, C-Silica, A-Sol-gel
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Year
2015
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Issue
45 (2)
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Pages
188-193
IULIA ROATEŞI
Abstract
Dental implants (DI) are biocompatible structures made of alloplastic materials that are inserted surgically in the bone crest to become outstanding infrastructure for prostheses or dentures. Materials used in DI manufacturing are represented mainly by titanium and its alloys, but can be also manufactured by zirconia, safirbioceramics, etc. This article is dedicated to a 3D finite element modeling of various types of DI to calculate the stress and distribution of safety factor under masticatory forces, and therefore to assess risk factors for DI design. This work represents an original study of accurate geometric models of various types of DI and therefore for their using in calculation to evaluate the risk zones in the whole structure made up of bone, implant and ceramic crown.
Keywords
dental implants, biomaterials, bioceramics, three-dimensional finite element analysis, numerical modeling, implant stability
CONSTANTIN VLAD DENIS, ALEXANDRU CARÂP, BOGDAN SOCEA, ANTON FICAI, MĂDĂLINA GEORGIANA ALBU, GEORGETA PĂUNICĂ - PANEA
Abstract
The repair of the abdominal wall defects has always been a challenge. Good long term results (low percentage of recurrences) represent the purpose of different surgical techniques. Modern techniques use various types of alloplastic materials, making it possible for a lower recurrence rate, under a certain assumed and acceptable level. In the case of alloplastic repair, the tolerance of the organism towards the non-biologic material should be taken into consideration. Three types of meshes made of different synthetic materials were characterized by mesh density, pore size, pore shape, material composition by FT-IR microscopy and mechanical properties. The present study retrospectively analyzes the results obtained in our clinic within 3 years (October 2011- October 2014), using alloplastic repair of the abdominal wall defects. The recurrence rate and the occurrence of different complications (seroma, postoperative leakage, mesh rejection, neuromas with postoperative pain) were studied using the three meshes.
Keywords
synthetic meshes, pore size, mechanical strength, hernia repair
MIHAELA VIOLETA GHICA, ANTON FICAI , ŞTEFANIA MARIN, MINODORA MARIN, ANA-MARIA ENE, JENEL MARIAN PĂTRAŞCU
Abstract
The aim of this study was to develop and characterize some new drug delivery systems based on collagen, bioactive (apatite – β-wollastonite) glass ceramics and doxycycline in order to be used in infected bone defects. The composites with different amount of glass ceramics were prepared as hydrogels by crosslinking and then freeze-dryed in order to obtain porous structures which mimic bone. The hydrogels were characterized by rheological behaviour and the the spongious forms by Fourier transform infrared spectroscopy (FT-IR) and water up-take. The in vitro behaviour was determined by collagenase degradation; the doxycycline release from spongious composite systems was investigated and the kinetic mechanism was determined. The results of this study indicated that the obtained composites are promising biomaterials for treatment and prevention of infected bone.
Keywords
collagen, bioactive glass ceramic, composite, drug delivery systems
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Year
2015
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Issue
45 (4)
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Pages
307-314
VLAD GABRIEL VASILESCU, MIRUNA SILVIA STAN, ION PĂTRAŞCU, ANCA DINISCHIOTU, ELISABETA VASILESCU
Abstract
In vitro testing of materials biocompatibility provides information on cell behavior in relation to chemical composition and surface topography of materials. The studied biomaterial is a new one proposed to be used in oral implantology and therefore requires studying its biocompatibility compared to conventional materials commonly used in oral implantology.
The in vitro response induced by this bioalloy with surface characteristics conferred by casting, corrosion and anodizing was evaluated on G292 human osteoblasts. The experimental obtained surface after anodizing presented a stable and consistent oxide "gel-looking” layer well highlighted in scanning electron microscopy images. The results demonstrated the ability of the biomaterial to support attachment, growth and proliferation of human osteoblasts. As compared to the other materials tested and demonstrates the improved properties that facilitated rapid cellular adaptation to these surfaces.
Keywords
biomaterial, biocompatibility, cell adhesion, osteoblasts
RODICA ROGOJAN , ECATERINA ANDRONESCU, MIHAI HOTETEU
Abstract
The purpose of this paper is to assess whether calcium phosphate nanoparticles may be potential carriers of different cations. Recent advances in nanotechnology show that nanoscale particles may play an important role in tissue engineering in medicine or in their use as substrates for controlled drug release. The calcium phosphate nanoparticles were obtained from (NH4)2HPO4 0.3 M and Ca(NO3)2∙4H2O 0.5 M by coprecipitation technique and the hybrids calcium phosphates - copper ions were obtained by the similar cold-wet method, in the presence of ammonium hydroxide. The synthesized samples were analyzed by X-ray diffractometry, Fourier transform infrared spectrofotometry (FT-IR), energy dispersive X-ray analysis (EDAX) and the micrographs were determined by scanning electron microscopy (SEM). Calcium phosphates are widely used as implantable bioactive agent that replaces defect bone tissues and can serve, also, as substrate for binding of cations, for provide bioactivity and biological interactions or could be used as drug deliveries.
Keywords
copper ions, calcium phosphates, hydroxiapatite, nanoparticle