Can inorganic bovine bone grafts present distinct properties?

The aim of this study was to evaluate the physicochemical characteristics of 3 mineralized bovine inorganic biomaterials and correlate them with the dissolution rate. Bio-Oss(r), GenoxInorgânico(r), and Bonefill(r) were examined using field emission gun scanning electron microscopy (FEG-SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), specific surface area (BET), calcium/phosphorous molar ratio and a dissolution assay. Bio-Oss(r) showed a micro- and nanoporous structure consisting of 15-nm hydroxyapatite (HA) crystallites; Genox(r), a microporous structure composed of 39-nm HA crystallites; and Bonefill(r), micro- and nanoporous structure of indeterminable crystallite size. FTIR analysis showed that Bio-Oss(r) and Genox(r) were composed of calcium phosphate. The absorption bands of phosphate were poorly defined in Bonefill(r). By XRD, Bio-Oss(r) was shown to contain peaks related to the carbonated HA, whereas Genox(r) only contained peaks corresponding to HA. The broad bands in Bonefill(r) indicated low crystallinity. Bio-Oss(r) showed a greater surface area and calcium release rate than that of Genox(r). Although all biomaterials were of bovine origin, the different manufacturing processes result in materials with different physicochemical properties and may influence the biological and clinical response.

Can Inorganic Bovine Bone Grafts Present Distinct Properties?

The aim of this study was to evaluate the physicochemical characteristics of 3 mineralized bovine inorganic biomaterials and correlate them with the dissolution rate. Bio-Oss(r), GenoxInorgânico(r), and Bonefill(r) were examined using field emission gun scanning electron microscopy (FEG-SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), specific surface area (BET), calcium/phosphorous molar ratio and a dissolution assay. Bio-Oss(r) showed a micro- and nanoporous structure consisting of 15-nm hydroxyapatite (HA) crystallites; Genox(r), a microporous structure composed of 39-nm HA crystallites; and Bonefill(r), micro- and nanoporous structure of indeterminable crystallite size. FTIR analysis showed that Bio-Oss(r) and Genox(r) were composed of calcium phosphate. The absorption bands of phosphate were poorly defined in Bonefill(r). By XRD, Bio-Oss(r) was shown to contain peaks related to the carbonated HA, whereas Genox(r) only contained peaks corresponding to HA. The broad bands in Bonefill(r) indicated low crystallinity. Bio-Oss(r) showed a greater surface area and calcium release rate than that of Genox(r). Although all biomaterials were of bovine origin, the different manufacturing processes result in materials with different physicochemical properties and may influence the biological and clinical response.

O objetivo deste estudo foi avaliar as características físico-químicas de 3 biomateriais bovinos inorgânicos mineralizados e correlacioná-los com a taxa de dissolução. Bio-Oss(r), Genox Inorgânico(r) e Bonefill(r) foram caracterizados por microscopia eletrônica de varredura com fonte de emissão por efeito de campo (MEV-FEG), espectroscopia de infravermelho com transformada de Fourier (FTIR), difração de raios-X (DRX), área superficial específica (BET), razão molar cálcio/fósforo e análise da dissolução. Bio-Oss(r) mostrou uma estrutura micro e nanoporosa consistindo de cristalitos de hidroxiapatita (HA) de 15 nm; Genox(r), uma estrutura microporosa composta de cristalitos de HA de 39 nm e Bonefill(r), estrutura micro e nanoporosa com tamanho indeterminável de cristalito. Análises de FTIR mostraram que Bio-Oss(r) e Genox(r) eram compostos por fosfato de cálcio. As bandas de absorção de fosfato encontraram-se pouco definidas no Bonefill(r). Por DRX, Bio-Oss(r) mostrou picos relacionados à HA carbonatada, enquanto Genox(r) somente apresentou picos correspondentes à HA; as bandas alargadas no Bonefill(r) indicaram baixa cristalinidade. Bio-Oss(r) apresentou maior área de superfície e taxa de liberação de cálcio quando comparado ao Genox(r). Embora todos os biomateriais fossem de origem bovina, os diferentes processos de manufatura resultam em materiais com diferentes propriedades físico-químicas e podem influenciar a resposta biológica e clínica.

Preparation, characterization and biological test of 3D-scaffolds based on chitosan, fibroin and hydroxyapatite for bone tissue engineering.

This work describes the preparation and characterization of porous 3D-scaffolds based on chitosan (CHI), chitosan/silk fibroin (CHI/SF) and chitosan/silk fibroin/hydroxyapatite (CHI/SF/HA) by freeze drying. The biomaterials were characterized by X-ray diffraction, attenuated total reflection Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy and energy dispersive spectroscopy. In addition, studies of porosity, pore size, contact angle and biological response of SaOs-2osteoblastic cells were performed. The CHI scaffolds have a porosity of 94.2±0.9%, which is statistically higher than the one presented by CHI/SF/HA scaffolds, 89.7±2.6%. Although all scaffolds were able to promote adhesion, growth and maintenance of osteogenic differentiation of SaOs-2 cells, the new 3D-scaffold based on CHI/SF/HA showed a significantly higher cell growth at 7 days and 21 days and the level of alkaline phosphatase at 14 and 21 days was statistically superior compared to other tested materials.

Synthesis and cytotoxicity evaluation of granular magnesium substituted ß-tricalcium phosphate.

OBJECTIVE: The aim of this study was to produce dense granules of tricalcium phosphate (ß-TCP) and magnesium (Mg) substituted ß-TCP, also known as ß-TCMP (Mg/Ca=0.15 mol), in order to evaluate the impact of Mg incorporation on the physicochemical parameters and in vitro biocompatibility of this novel material. MATERIAL AND METHODS: The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy and inductively coupled plasma (ICP). Biocompatibility was assayed according to ISO 10993-12:2007 and 7405:2008, by two different tests of cell survival and integrity (XTT and CVDE). RESULTS: The XRD profile presented the main peaks of ß-TCP (JCPDS 090169) and ß-TCMP (JCPDS 130404). The characteristic absorption bands of TCP were also identified by FTIR. The ICP results of ß-TCMP granules extract showed a precipitation of calcium and release of Mg into the culture medium. Regarding the cytotoxicity assays, ß-TCMP dense granules did not significantly affect the mitochondrial activity and relative cell density in relation to ß-TCP dense granules, despite the release of Mg from granules into the cell culture medium. CONCLUSION: ß-TCMP granules were successfully produced and were able to release Mg into media without cytotoxicity, indicating the suitability of this promising material for further biological studies on its adequacy for bone therapy.

Synthesis and cytotoxicity evaluation of granular magnesium substituted beta-tricalcium phosphate

Objective: The aim of this study was to produce dense granules of tricalcium phosphate (β-TCP) and magnesium (Mg) substituted β-TCP, also known as β-TCMP (Mg/Ca=0.15 mol), in order to evaluate the impact of Mg incorporation on the physicochemical parameters and in vitro biocompatibility of this novel material. Material and Methods: The materials were characterized using X-ray diffraction (XRD), infrared spectroscopy (FTIR), electron microscopy and inductively coupled plasma (ICP). Biocompatibility was assayed according to ISO 10993-12:2007 and 7405:2008, by two different tests of cell survival and integrity (XTT and CVDE). Results: The XRD profile presented the main peaks of β-TCP (JCPDS 090169) and β-TCMP (JCPDS 130404). The characteristic absorption bands of TCP were also identified by FTIR. The ICP results of β-TCMP granules extract showed a precipitation of calcium and release of Mg into the culture medium. Regarding the cytotoxicity assays, β-TCMP dense granules did not significantly affect the mitochondrial activity and relative cell density in relation to β-TCP dense granules, despite the release of Mg from granules into the cell culture medium. Conclusion: β-TCMP granules were successfully produced and were able to release Mg into media without cytotoxicity, indicating the suitability of this promising material for further biological studies on its adequacy for bone therapy.

Evaluation of implant-abutment microgap and bacterial leakage in five external-hex implant systems: an in vitro study.

PURPOSE: The aim of the present study was to verify the presence of a microgap between implants and prosthetic abutments on their external surfaces in five different external-hex implant systems and to determine whether bacterial leakage occurs through the implant-abutment (I-A) interface. MATERIALS AND METHODS: Ten samples of each implant system were used. Eight samples of each implant system were inoculated with 0.3 µL of a suspension of Escherichia coli for bacterial leakage evaluation. Two other samples were used as controls. Sample analysis was accomplished at 24 and 48 hours and on the 5th, 7th, and 14th day after inoculation. After microbiologic analysis, all samples were prepared for I-A interface evaluation by scanning electron microscopy. The mean of the microgap misfit was obtained from six points at x1,000 and x3,000 magnifications. RESULTS: The Neodent implant system (0.51 ± 0.39 µm) showed the closest adaptation, followed by Dentoflex (1.44 ± 0.73 µm), Titanium Fix (1.88 ± 1.28 µm), SIN (2.46 ± 3.38 µm), and Conexão (2.68 ± 3.02 Μm). Twenty-five percent of the Dentoflex samples showed bacterial leakage through the I-A interface; no other implant system presented bacterial leakage. CONCLUSION: The width of the microgap at the I-A interface was less than 3 µm in all systems. A direct correlation between bacterial leakage and I-A interface misfit was not observed.

Histomorphometric analysis of tissue responses to bioactive glass implants in critical defects in rat calvaria.

The aim of this study was to evaluate the osteogenic behavior of two chemically similar bioactive glass products (Biogranand Perioglas) implanted in critical bone defects in rat calvaria. Thirty-six transfixed bone defects of 8 mm diameter were made surgically in adult male Wistar rats. The animals were distributed equally into three groups: Biogran (GI), Perioglas (GII) and without implant material (control; GIII). The morphology and composition of both bioactive glasses were analyzed by scanning electron microscopy and energy-dispersive spectrometry. Tissue specimens were analyzed at the biological time points of 15, 30 and 60 days by optical microscopy and morphometry, demonstrating biocompatibility for the tested materials with moderate chronic inflammation involving their particles. Bone neoformation resulted only as a reparative reaction to an intentionally produced defect and was limited to the defect's edges. No statistically significant differences among the groups were observed. At the scar interstice, abundant deposits of collagenous fibers enveloping the particles were noted. The present results indicated that the bioactive glasses, under the experimental conditions analyzed, did not show osteogenic behavior.