Carbonated Hydroxyapatite Layer Research Articles

Bioactive glass for periodontal regeneration: a systematic review

BackgroundOne of the major clinical challenges of this age could be represented by the possibility to obtain a complete regeneration of infrabony defects. Over the past few years, numerous materials and different approaches have been developed to obtain bone and periodontal healing. Among all biomaterials, bioglasses (BG) are one of the most interesting due to their ability to form a highly reactive carbonate hydroxyapatite layer. Our aim was to systematically review the literature on the use and capability of BG for the treatment of periodontal defects and to perform a meta-analysis of their efficacy.MethodsA search of MEDLINE/PubMed, Cochrane Library, Embase and DOSS was conducted in March 2021 to identify randomized controlled trials (RCTs) using BG in the treatment of intrabony and furcation defects. Two reviewers selected the articles included in the study considering the inclusion criteria. The outcomes of interest were periodontal and bone regeneration in terms of decrease of probing depth (PD) and gain of clinical attachment level (CAL). A network meta-analysis (NMA) was fitted, according to the graph theory methodology, using a random effect model.ResultsThrough the digital search, 46 citations were identified. After duplicate removal and screening process, 20 articles were included. All RCTs were retrieved and rated following the Risk of bias 2 scale, revealing several potential sources of bias. The meta-analysis focused on the evaluation at 6 months, with 12 eligible articles for PD and 10 for CAL. As regards the PD at 6 months, AUTOGENOUS CORTICAL BONE, BIOGLASS and PLATELET RICH FIBRIN were more efficacious than open flap debridement alone, with a statistically significant standardized mean difference (SMD) equal to -1.57, -1.06 and − 2.89, respectively. As to CAL at 6 months, the effect of BIOGLASS is reduced and no longer significant (SMD = -0.19, p-value = 0.4) and curiously PLATELET RICH FIBRIN was more efficacious than OFD (SMD =-4.13, p-value < 0.001) in CAL gain, but in indirect evidence.ConclusionsThe present review partially supports the clinical efficacy of BG in periodontal regeneration treatments for periodontal purposes. Indeed, the SMD of 0.5 to 1 in PD and CAL obtained with BG compared to OFD alone seem clinically insignificant even if it is statistically significant. Heterogeneity sources related to periodontal surgery are multiple, difficult to assess and likely hamper a quantitative assessment of BG efficacy.

Structure, properties and in-vitro response of SiO2-Na2O-CaO-P2O5 system based glass-ceramics after partial replacement of Na2O by Li2O

Effect of lithium oxide substitution on the structure, in-vitro chemical dissolution and mechanical properties of melt derived 45S5 based glass-ceramics in 46.1SiO2 (24.4-x)Na2O 26.9CaO 2.6P2O5 x Li2O (x = 0, 2, 4, 6, and 10 mole %) system was studied. Raman analysis had shown the presence of Q2 silica tetrahedra and crystalline phosphorus in the glass-ceramics samples. Higher mechanical properties of lithia containing glass and glass-ceramics were noticed due to compact glass structure in presence of small sized Li+ ions. Hexagonal shaped combeite (Na2O.2CaO.3SiO2) was the only crystalline phase. Fourier transform infrared spectroscopy (FTIR) and Raman spectra confirmed formation of carbonated hydroxyapatite (HCA) on the glass-ceramics surface in SBF solution. Scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) corroborated cotton ball like morphology as carbonated hydroxyapatitel ayer on lithium containing glass-ceramics sample surface.

Sustained Calcium(II)-Release to Impart Bioactivity in Hybrid Glass Scaffolds for Bone Tissue Engineering.

In this study, we integrated different calcium sources into sol-gel hybrid glass scaffolds with the aim of producing implants with long-lasting calcium release while maintaining mechanical strength of the implant. Calcium(II)-release was used to introduce bioactivity to the material and eventually support implant integration into a bone tissue defect. Tetraethyl orthosilicate (TEOS) derived silica sols were cross-linked with an ethoxysilylated 4-armed macromer, pentaerythritol ethoxylate and processed into macroporous scaffolds with defined pore structure by indirect rapid prototyping. Triethyl phosphate (TEP) was shown to function as silica sol solvent. In a first approach, we investigated the integration of 1 to 10% CaCl2 in order to test the hypothesis that small CaCl2 amounts can be physically entrapped and slowly released from hybrid glass scaffolds. With 5 and 10% CaCl2 we observed an extensive burst release, whereas slightly improved release profiles were found for lower Calcium(II) contents. In contrast, introduction of melt-derived bioactive 45S5 glass microparticles (BG-MP) into the hybrid glass scaffolds as another Calcium(II) source led to an approximately linear release of Calcium(II) in Tris(hydroxymethyl)aminomethane (TRIS) buffer over 12 weeks. pH increase caused by BG-MP could be controlled by their amount integrated into the scaffolds. Compression strength remained unchanged compared to scaffolds without BG-MP. In cell culture medium as well as in simulated body fluid, we observed a rapid formation of a carbonated hydroxyapatite layer on BG-MP containing scaffolds. However, this mineral layer consumed the released Calcium(II) ions and prevented an additional increase in Calcium(II) concentration in the cell culture medium. Cell culture studies on the different scaffolds with osteoblast-like SaOS-2 cells as well as bone marrow derived mesenchymal stem cells (hMSC) did not show any advantages concerning osteogenic differentiation due to the integration of BG-MP into the scaffolds. Nonetheless, via the formation of a hydroxyapatite layer and the ability to control the pH increase, we speculate that implant integration in vivo and bone regeneration may benefit from this concept.

RETRACTED ARTICLE: Investigation of the structural properties and bioactivity of P2O5–CaO–Na2O–TiO2 glass and glass-ceramics synthesized via a novel sol–gel method by acetone and DMF solvents

Because of the significant effect of the sol–gel method on the glass morphology at the relatively low processing temperature, in the present work, phosphate glass and glass-ceramic nanopowders with the general formula of (P2O5)55–CaO)25–(Na2O)20−x–(TiO2)x, (x = 5, 10, and 15 mol%) have been synthesized via a facile sol–gel method. For this purpose, acetone and dimethylformamide (DMF) have been used as a polar and non-protic solvent. The proportion of triethylphosphate to acetone or DMF has been selected 1:3 that they have been synthesized at 25 °C and pH = 5–6. The glass powders have been dried at 315 °C. Then, the powders synthesized by acetone have been calcined at 500 and 750 °C, and the powders synthesized by DMF have been calcined at 550, 650, and 750 °C. The glass and glass-ceramic nanopowders have been analyzed by several techniques, X-ray powder diffraction (XRD), Differential thermal analysis (STA), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller and Barrett–Joyner–Halenda (BET–BJH), and Scanning electron microscopy (SEM-EDS). The XRD results have been confirmed the amorphous nature of all glass samples, while after calcination, the samples have been shown the peaks assigned to β-TCP and hydroxyapatite. The SEM images have shown that the synthesized glass and glass-ceramic powders by both acetone and DMF solvents have a particle size below 50 nm and spherical morphology. Also, the glass and glass-ceramic powders, after soaking in the simulated body fluid (SBF) for 7 days, depicted the formation of hydroxyapatite and carbonated-hydroxyapatite layer on the surface of the glass and glass-ceramic powders, respectively.

Preparation of β-Ca3(PO4)2/Poly(D,L-lactide) and β-Ca3(PO4)2/Poly(ε-caprolactone) Biocomposite Implants for Bone Substitution

Highly permeable macroporous implants of various architectures for bone grafting have been fabricated by thermal extrusion 3D printing using highly filled β-Ca3(PO4)2/poly(D,L-lactide) (degree of filling up to 70 wt %) and β-Ca3(PO4)2/poly(e-caprolactone) (degree of filling up to 70 wt %) composite filaments. To modify the surface of the composite macroporous implants with the aim of improving their wettability by saline solutions, we have proposed exposing them to a cathode discharge plasma (2.5 W, air as plasma gas) in combination with subsequent etching in a 0.5 M citric acid solution. It has been shown that the main contribution to changes in the wettability (contact angle) of the composites is made by the changes produced in their surface morphology by etching in a low-temperature plasma and citric acid. An alternative approach to surface modification of the composites is to produce a carbonate hydroxyapatite layer via precipitation from a simulated body fluid solution a factor of 5 supersaturated relative to its natural analog (5xSBF).

Bioactive ceramic powder prepared using a new sol-gel process

Bioactive ceramic powder containing 45% SiO2, 24.5% CaO, 24.5% Na2O and 6% P2O5 (wt.%) was synthesized using a new sol-gel process. The preparedmaterial was investigated by several physico-chemical methods. The X-ray diffraction showed the presence of two crystalline phases, Na6Ca3Si6O18 and NaCaPO4. The high specific surface area (47m2/g) and a mesoporous structure with the average pore size of 2.6 nm were confirmed using low-temperature nitrogen adsorption technique. In vitro experiments were carried out by soaking the powder sample in simulated body fluid (SBF) at different times. XRD, FTIR and SEM coupled with EDS were used for in vitro evaluation of bioactivity. The obtained results confirmed that the ceramic powder can be used as biomaterial for bone tissue engineering due to its high bioactivity expressed by the rapid formation of a biological carbonated hydroxyapatite layer on its surface after in vitro assay.

Porous SiO2 nanofiber grafted novel bioactive glass–ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant

A composite bioactive glass–ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface.

Formation andin vitrobiocompatibility of biomimetic hydroxyapatite coatings on chemically treated carbon substrates

Carbon derived materials such as pyrolytic carbon or carbon-carbon composites (CCCs) exhibit excellent mechanical properties making them promising candidates for bone replacement. However, these materials are considered bioinert and not to induce bone formation in vivo. In this study, a two-step chemical surface treatment including etching with HCl/HNO3 solution and subsequent soaking in CaCl2 solution was applied to carbon substrates in order to activate the materials surface towards bioactive behavior. The bioactivity was proven by soaking the samples in simulated body fluid (SBF) and formation of carbonated hydroxyapatite layer (HCA), which indicates the ability of the material to bond to bone in vivo. The materials surface is shown to be functionalized through the chemical etching creating COO(-)Ca(2+) complexes on the surface as confirmed by FTIR and XPS analyses. These ionic complexes provide nucleation sites for HAp precipitation. After similar immersion time in SBF under the condition of local supersaturation the thickness and homogeneity of the HAp layer were found to depend on the chemical pretreatment with HCl/HNO3. Homogenous HAp layers with a thickness ranging from ∼ 6 to ∼ 17 μm were achieved. The proposed bioactivating treatment of carbon stimulates HAp formation in vivo and can be considered an easy biomimetic approach for coating carbon derived materials with bone-like hydroxyapatite. In vitro cell assay with osteosarcoma cells (MG-63) showed increased cell viability (+70%) on HAp coated carbon substrates as compared to uncoated reference while both materials induced ALP expression in MG-63 cells confirming the osteoblastic phenotype.

In vitro reactivity of Cu doped 45S5 Bioglass® derived scaffolds for bone tissue engineering.

Cu-doped 45S5 bioactive glasses with varying Cu contents were fabricated and used to process 3D porous scaffolds via the foam replica technique. Cu-doping results in the weakening of the glass network and a decrease in its glass transition temperature. Acellular in vitro studies revealed very high bioactivity independent of Cu doping as indicated by the fast formation of a carbonated hydroxyapatite layer (CHA) on scaffold surfaces after immersion in simulated body fluid (SBF). The kinetics of the glass-ceramic scaffold's transition to an amorphous calcium phosphate layer (ACP) and the crystallisation of CHA were explored by FT-IR and SEM analyses. The elemental distribution in the scaffold/fluid interface region was monitored by the advanced micro-PIXE-RBS (particle induced X-ray emission/Rutherford backscattering spectrometry) method. Cu-containing glasses showed slower release of Si, Ca and P from the scaffold periphery, whereas traces of Cu were found incorporated in the CaP layer on the scaffold surface. Cu release kinetics from the scaffolds in SBF were found to depend on culturing conditions while highest Cu concentrations of ∼3.1 ppm and ∼4.6 ppm under static and quasi-dynamic conditions, respectively, were observed. Since Cu exhibits potential angiogenic and osteogenic properties, the Cu-containing scaffolds are suggested as promising materials for bone tissue engineering applications.

Bioactive glass microspheres as reinforcement for improving the mechanical properties and biological performance of poly(ε‐caprolactone) polymer for bone tissue regeneration

This study examined the utility of sol-gel-derived bioactive glass microspheres (BGMs) as a reinforcement to improve the mechanical properties and biological performance of poly(ε-caprolactone) (PCL) polymer. All of the PCL-BGMs composites produced, with a variety of BGMs contents (10, 20, and 30 wt %), showed a uniform distribution of the BGMs in the PCL matrix, particularly owing to their spherical shape and small size. This led to a considerable increase in the elastic modulus from 93 ± 12 MPa to 635 ± 179 MPa with increasing BGMs content from 0 to 30 wt %. Furthermore, the addition of the BGMs to the PCL polymer significantly increased the hydrophilicity of the PCL-BGMs composites, which led to a higher water absorption and degradation rate. The PCL-BGMs composite with a BGMs content of 30 wt % showed vigorous growth of apatite crystals with a high aspect ratio on its surface after soaking in the simulated body fluid for 7 days, resulting in the creation of a porous carbonate hydroxyapatite layer.

Effect of carbon interlayer on protective properties of hydroxyapatite coating deposited on 316L stainless steel by sol-gel method

Good-quality bilayer coatings with a carbon interlayer and outer carbonate hydroxyapatite layer are obtained on AISI 316L stainless steel substrate using RF PACVD and sol-gel methods. It is found that protective properties of both composite C/HAP coating and HAP coating depend on the temperature of heat treatment. Hydroxyapatite with a carbon interlayer coating annealed at 500°C significantly improves corrosion resistance of the stainless-steel substrate as well as of unary carbon and HAP coatings. The composite C/HAP coating annealed at 500°C exhibits better corrosion resistance in comparison with the HAP coating heated at the same temperature. Stainless-steel substrates with a HAP and C interlayer heated at 700°C have worse corrosion features in comparison with uncoated AISI 316L. The weak corrosion resistance of this sample is due to the formation of metal carbides at this temperature.

Biomineralization capability of adherent bio-glass films prepared by magnetron sputtering

Radiofrequency magnetron sputtering deposition at low temperature (150 degrees C) was used to deposit bioactive glass coatings onto titanium substrates. Three different working atmospheres were used: Ar 100%, Ar + 7%O(2), and Ar + 20%O(2). The preliminary adhesion tests (pull-out) produced excellent adhesion values (approximately 75 MPa) for the as-deposited bio-glass films. Bioactivity tests in simulated body fluid were carried out for 30 days. SEM-EDS, XRD and FTIR measurements were performed. The tests clearly showed strong bioactive features for all the prepared films. The best biomineralization capability, expressed by the thickest chemically grown carbonated hydroxyapatite layer, was obtained for the bio-glass coating sputtered in a reactive atmosphere with 7% O(2).

Ceramics for medical applications

Ceramics, glasses and glass ceramics include a broad range of inorganic non-metallic compositions. The apatite and related calcium phosphates have been of remarkable interest to biologists, mineralogists, inorganic and industrial chemists for many years. Calcium phosphate biomaterials, mainly hydroxyapatite, find many clinical applications in the repair of bone defects, bone augmentation and coatings for metal implants. Certain compositions of ceramics, glasses, glass ceramics and composites have shown bone bonding behaviour. These materials have become known as bioactive ceramics. A common characteristic of bioactive ceramics is a time-dependent, kinetic modification of the surface that occurs upon implantation. The surface forms a biologically active carbonate hydroxyapatite layer that provides the bonding interface with living tissues. The aim of this perspective is to present an overview of the different types of ceramics available for medical applications, focused mainly on bioactive glasses.

New Bioactive Glass and Changes in Porosity during the Growth of a Carbonate Hydroxyapatite Layer on Glass Surfaces

The synthesis of a bioactive glass with a composition (in mole %) SiO2 (55), CaO (41), P2O5 (4) was carried out by the sol−gel method. The in vitro bioactivity of this glass was assessed by following the changes in surface composition and morphology after soaking in simulated body fluid (SBF) for several periods. Also the porosity of the glass was studied by considering the changes of that porosity when a carbonate hydroxyapatite (CHA) layer grows on the glass surface. The glass synthesized in this work shows a high degree of porosity due to its elevated content in Ca(II), which is released from the glass to the media. This dilution of Ca2+, which gives rise to macropore enhancement together with the saturation of the media, leads to a fast growth of CHA on glass surface and pores.

Gentamicin release from hydroxyapatite/poly(ethyl methacrylate)/poly(methyl methacrylate)composites.

In this work the release kinetics of gentamicin sulfate (GEN) in samples composed by hydroxyapatite, poly(methyl methacrylate), and poly(ethyl methacrylate) has been studied. The release study was performed by soaking three samples in simulated body fluid at 37 degrees C; the medium was periodically replaced during 70 days. The concentration of GEN was determined by the o-phtaldialdehyde method. The release profile shows three stages: the first stage, occurring during the first 10 h, corresponds to a fast release (nearly 30% of the drug is released in this period). The second stage is slower and includes from the first 10 h to 16 days, releasing 60% of the total amount of GEN. The final stage is the slowest and it takes from 16 to 70 days (10% of GEN is released). The fraction of released GEN versus square root of time can be fitted to a third order polynomial, corresponding with the model proposed by Cobby et al. (J Pharm Sci 1974;63:725-732). The characterization of the samples after the release study shows that a carbonate hydroxyapatite layer has grown on the whole surface of the composites.