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International Journal of Molecular... Nov 2022The aim of the study was to analyze the chemical−physical properties and bioactivity (apatite-forming ability) of three recently introduced premixed bioceramic root...
The aim of the study was to analyze the chemical−physical properties and bioactivity (apatite-forming ability) of three recently introduced premixed bioceramic root canal sealers containing varied amounts of different calcium silicates (CaSi): a dicalcium and tricalcium silicate (1−10% and 20−30%)-containing sealer with zirconium dioxide and tricalcium aluminate (CERASEAL); a tricalcium silicate (5−15%)-containing sealer with zirconium dioxide, dimethyl sulfoxide and lithium carbonate (AH PLUS BIOCERAMIC) and a dicalcium and tricalcium silicate (10% and 25%)-containing sealer with calcium aluminate, tricalcium aluminate and tantalite (NEOSEALER FLO). An epoxy resin-based sealer (AH PLUS) was used as control. The initial and final setting times, radiopacity, flowability, film thickness, open pore volume, water absorption, solubility, calcium release and alkalizing activity were tested. The nucleation of calcium phosphates and/or apatite after 28 days aging in Hanks balanced salt solution (HBSS) was evaluated by ESEM-EDX, vibrational IR and micro-Raman spectroscopy. The analyses showed for NeoSealer Flo and AH Plus the longest final setting times (1344 ± 60 and 1300 ± 60 min, respectively), while shorter times for AH Plus Bioceramic and Ceraseal (660 ± 60 and 720 ± 60 min, respectively). Radiopacity, flowability and film thickness complied with ISO 6876/12 for all tested materials. A significantly higher open pore volume was observed for NeoSealer Flo, AH Plus Bioceramic and Ceraseal when compared to AH Plus (p < 0.05), significantly higher values were observed for NeoSealer Flo and AH Plus Bioceramic (p < 0.05). Ceraseal and AH Plus revealed the lowest solubility. All CaSi-containing sealers released calcium and alkalized the soaking water. After 28 days immersion in HBSS, ESEM-EDX analyses revealed the formation of a mineral layer that covered the surface of all bioceramic sealers, with a lower detection of radiopacifiers (Zirconium for Ceraseal and AH Plus Bioceramic, Tantalum for NeoSealer Flo) and an increase in calcium, phosphorous and carbon. The calcium phosphate (CaP) layer was more evident on NeoSealer Flo and AH Plus Bioceramic. IR and micro-Raman revealed the formation of calcium carbonate on the surface of all set materials. A thin layer of a CaP phase was detected only on AH Plus Bioceramic and NeoSealer Flo. Ceraseal did not show CaP deposit despite its highest calcium release among all the tested CaSi-containing sealers. In conclusion, CaSi-containing sealers met the required chemical and physical standards and released biologically relevant ions. Slight/limited apatite nucleation was observed in relation to the high carbonation processes.
Topics: Root Canal Filling Materials; Calcium; Dental Pulp Cavity; Silicates; Water; Apatites
PubMed: 36430393
DOI: 10.3390/ijms232213914 -
Methods in Molecular Biology (Clifton,... 2023Hydroxyapatite (HA) is a mixed-mode media that has been used extensively for the purification of proteins and DNA since the 1950s. Hydroxyapatite possesses a distinctive...
Hydroxyapatite (HA) is a mixed-mode media that has been used extensively for the purification of proteins and DNA since the 1950s. Hydroxyapatite possesses a distinctive selectivity that may be applied in the purification of a wide range of biomolecules: immunoglobulins, alkaline proteins, acidic proteins, and DNA. The functional groups of HA can both attract and repel the carboxyl and amino groups on target molecules. This unique selectivity is due to the modalities that can be employed, which are not possible with traditional anion-exchange and cation-exchange chromatography. HA is a powerful chromatography step for reducing host cell-derived impurities and aggregated product, where a 2-4 log reduction in host cell proteins, aggregates, endotoxin, and viruses are routinely achieved. This chapter describes the procedures for: efficiently packing and evaluating a HA column, purifying IgG and acidic proteins respectively using HA chromatography.
Topics: Chromatography; Durapatite; Endotoxins
PubMed: 37646999
DOI: 10.1007/978-1-0716-3362-5_10 -
Journal of Oral Biosciences Sep 2020Osteocalcin is the most abundant non-collagenous protein in bone and is specifically expressed in osteoblasts. Previous studies using osteocalcin-deficient (Ocn) mice... (Review)
Review
BACKGROUND
Osteocalcin is the most abundant non-collagenous protein in bone and is specifically expressed in osteoblasts. Previous studies using osteocalcin-deficient (Ocn) mice demonstrated that osteocalcin inhibits bone formation, and serum uncarboxylated osteocalcin functions as a hormone that improves glucose metabolism, induces testosterone synthesis in the testes, and maintains muscle mass. Furthermore, the relationship between serum osteocalcin and glucose metabolism or cardiovascular risk in humans has been reported. However, new Ocn mice exhibited different phenotypes.
HIGHLIGHT
Bone volume, formation, and resorption were normal in the new Ocn mice. The orientation of collagen fibers was parallel to the bone longitudinal direction and the size of apatite crystals was normal, but the c-axis of apatite crystals was random and bone strength was reduced in new Ocn mice. Glucose metabolism, testosterone synthesis, and muscle mass were normal in new Ocn mice. Exercise improved glucose metabolism and increased bone formation, leading to an increase in the serum osteocalcin level, which is a marker for bone formation.
CONCLUSION
Contrary to previous findings, new Ocn mice revealed that osteocalcin has no function in the regulation of bone quantity, but instead, functions to direct the parallel alignment of the c-axis of apatite crystals with collagen fibrils. Moreover, it has no physiological function as a hormone that regulates glucose metabolism, testosterone synthesis, or muscle mass. These controversial phenotypes require further investigation. The relationship of serum osteocalcin with glucose metabolism or cardiovascular risk suggests the importance of exercise for their improvement.
Topics: Animals; Apatites; Bone and Bones; Male; Mice; Osteoblasts; Osteocalcin; Osteogenesis
PubMed: 32535287
DOI: 10.1016/j.job.2020.05.004 -
International Journal of Molecular... Aug 2022Apatites are one of the most intensively studied materials for possible biomedical applications. New perspectives of possible application of apatites correspond with the...
Apatites are one of the most intensively studied materials for possible biomedical applications. New perspectives of possible application of apatites correspond with the development of nanomaterials and nanocompounds. Here, an effort to systematize different kinds of human bioapatites forming bones, dentin, and enamel was undertaken. The precursors of bioapatites and hydroxyapatite were also considered. The rigorous consideration of compositions and stoichiometry of bioapatites allowed us to establish an order in their mutual sequence. The chemical reactions describing potential transformations of biomaterials from octacalcium phosphate into hydroxyapatite via all intermediate stages were postulated. Regardless of whether the reactions occur in reality, all apatite biomaterials behave as if they participate in them. To conserve the charge, additional free charges were introduced, with an assumed meaning to be joined with the defects. The distribution of defects was coupled with the values of crystallographic parameters "" and "". The energetic balances of bioapatite transformations were calculated. The apatite biomaterials are surprisingly regular structures with non-integer stoichiometric coefficients. The results presented here will be helpful for the further design and development of nanomaterials.
Topics: Apatites; Biocompatible Materials; Bone and Bones; Crystallography; Durapatite; Humans
PubMed: 36076932
DOI: 10.3390/ijms23179537 -
RoFo : Fortschritte Auf Dem Gebiete Der... Aug 2021
Topics: Apatites; Buttocks; Calcium; Humans; Tendinopathy; Tendons
PubMed: 33772492
DOI: 10.1055/a-1352-5432 -
Atencion Primaria 2019
Topics: Adult; Apatites; Female; Humans; Kidney Calculi; Low Back Pain; Proteus mirabilis; Struvite; Tomography, X-Ray Computed
PubMed: 30732968
DOI: 10.1016/j.aprim.2018.09.014 -
Dental Materials : Official Publication... Nov 2022The aim of this study was to investigate the degradation of inert glass fillers which are commonly used in conventional resin-based composites to provide radiopacity,...
OBJECTIVES
The aim of this study was to investigate the degradation of inert glass fillers which are commonly used in conventional resin-based composites to provide radiopacity, reduce the polymerization shrinkage and improve the mechanical properties.
METHODS
75 mg of five different glass powders (1 µm) was immersed separately into 50 mL of acetic acid (pH 4) and tris buffer (pH 7.4) for up to 4 weeks. At each time point the glass powder was filtered and dried for characterization using ATR-FTIR and XRD to assess the degradation behavior and crystallization. ICP-OES, ISE and pH measurements were performed on the supernatant solutions to monitor the pH and ion release.
RESULTS
Although FTIR and XRD analysis showed no significant glass degradation or crystallization upon immersion, there was a substantial release of ions from the inert fillers, especially from BABFG and CDL. Barium release for these fillers were 270 and 165 ppm respectively. G018-373 glass presented the lowest ion release followed by GM27884 and BABG. The ion release was more pronounced in acidic conditions compared to neutral conditions apart from the fluoride release.
SIGNIFICANCE
Inert glasses are not as inert as previously thought. This may result in leaching of ions, potentially causing toxicity, reduction in mechanical properties, increased wear and subsequent failure of the composite material. The ions released from the inert glass may interfere with other glass fillers such as bioactive glass fillers, inhibiting degradation of the bioactive glass, beneficial ion release from the bioactive glass, pH neutralization and apatite formation.
Topics: Apatites; Barium; Fluorides; Glass; Materials Testing; Powders; Tromethamine
PubMed: 36154969
DOI: 10.1016/j.dental.2022.09.004 -
Scientific Reports Jul 2023According to the previous studies of sialolithiasis reported so far, this study is aimed to identify the biological components of sialolith, which show different...
According to the previous studies of sialolithiasis reported so far, this study is aimed to identify the biological components of sialolith, which show different ultrastructures and chemical compositions from other stones, cholelith and urolith. Twenty-two specimens obtained from 20 patients were examined histologically, and analyzed with micro-CT, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). All sialoliths (n = 22) observed in this study showed a central nidus, which was filled with organoid matrix admixed with exosome vesicles, loose calcium apatite crystals, and many bacteria. The micro-CT and SEM observation clearly defined a single or multiple central nidus(es) encircled by highly calcified compact zone. The circular compact zone showed a band-like calcification, about 1-3 mm in thickness, and usually located between the central nidus and the peripheral multilayer zone. But some sialoliths (n = 5) showed severe erosion of compact zone by expanding multilayered zone depending on the level of calcification and inflammation in sialolith. By observing TEM images, many exosome vesicles and degraded cytoplasmic organelles were found in the central nidus, and some epithelial cells were also found in the calcified matrix of peripheral multilayer zone. Particularly, EDS analysis indicated the highest Ca/P ratio in the intermediate compact zone (1.77), and followed by the central nidus area (1.39) and the peripheral multilayer zone (0.87). Taken together, these data suggest that the central nidus containing many inflammatory exosomes and degraded cytoplasmic organelles has a potential to induce a band-like calcification of compact zone, and followed by the additional multilayer deposition of exfoliated salivary epithelial cells as well as salivary materials. Thereby, the calcium apatite-based sialolith is gradually growing in its volume size, and eventually obstructs the salivary flow and provides a site for the bacterial infection.
Topics: Humans; Salivary Gland Calculi; Calcium; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Calcinosis; Apatites
PubMed: 37507401
DOI: 10.1038/s41598-023-37462-w -
Journal of Stomatology, Oral and... Nov 2022The aim of this review was to evaluate the properties of chitosan for an application in dental implantology. (Review)
Review
OBJECTIVE
The aim of this review was to evaluate the properties of chitosan for an application in dental implantology.
METHODS
Electronic Databases: PubMed, Google Scholar, Scopus, were used to recherche the articles published from 2010 to 2021. The keywords used were: chitosan, biocompatible, antibacterial, osseointegration, implant, bioactive. After a carefully selection according to the above keywords 46 articles met the condition to be studied RESULTS: Chitosan is a biopolymer, that can be easy produced. Its antibacterial, anti-inflammatory, anti-fugal, hemostatic, analgesic, mucoadhesive, osseointegrative properties and its excellent film-forming ability make chitosan a material with a future in dental implantology and in other areas of dental applications. Titan implants coated with chitosan showed better bioactive properties than uncoated implants. The treatment of the implant surface played an important role on the stability of implants. The activity of osteoblasts increased when the surface was laser-treated followed by coating with chitosan. The subsequent coating with apatite improved the bioactivity of chitosan.
CONCLUSION
Chitosan is a promising biocompatible and bioactive material in dental implantology. Its antibacterial properties can be enhanced by modification of its structure. Its bioactive properties can be improved when mixing with hydroxy apatite.
Topics: Humans; Chitosan; Coated Materials, Biocompatible; Titanium; Dental Implants; Anti-Bacterial Agents; Apatites
PubMed: 35183801
DOI: 10.1016/j.jormas.2022.02.006 -
Scientific Reports Nov 2023The need for bioactive and non-toxic biomaterials is on a high demand in tissue engineering applications nowadays. Hydroxyapatite (HAp) is the chief constituent of teeth...
The need for bioactive and non-toxic biomaterials is on a high demand in tissue engineering applications nowadays. Hydroxyapatite (HAp) is the chief constituent of teeth and bones in mammas. One of the major challenges with the use of HAp in engineering application is its brittleness and to overcome this, it's important to react it with a material that can enhanced it's fragility. To this end, HAp and HAp/clay nanocomposites were developed via wet chemical process to mimic natural HAp and to equally confer special properties such as mechanical properties, high surface area, crystallinity, high porosity, and biocompatibility on the biomaterial. The functional groups properties of the as-prepared nanocomposites analyzed by FT-IR showed that the HAp and clay posed reactive centers such as Al-Al-OH, Si-Si-OH, Si-O, PO, -OH, and Si-O-Al. The XRD results confirmed the formation of HAp/clay nanocomposite, while SEM and TEM images showed the morphologies of the prepared nanocomposites to be round shape particles. Besides, EDX result revealed the Ca/P ratio of HAp and HAp-C to be lower than that of stoichiometric ratio (1.67) which implies the presence of K, Na, Ca, Mg, Si and Al in the HAp/clay nanocomposite. The mechanical properties of the apatite were greatly enhanced by the addition of clay. The physiological behaviour of the fabricated apatite composites in saline solution showed steady increase in the values of the saline pH of the various biomolecules until day 5 and became fairly constant at day 7 with pH range of 7.30-7.38. Though the saline solution was acidic at the beginning due to dissolved carbon dioxide, the pH of the saline solution containing the nanocomposites gradually became neutral and fairly alkaline over time as a result of the presence of Lewis basis structures in the composites which helps in neutralizing the acidic solution. Furthermore, proliferation of apatites particles onto the surface of the nanocomposites was observed after treatment with simulated body fluids (SBF) media for 7 days. Thus, HAp/clay nanocomposites can be useful biomaterials in bone tissue engineering.
Topics: Durapatite; Clay; Spectroscopy, Fourier Transform Infrared; Saline Solution; Biocompatible Materials; Nanocomposites; Apatites
PubMed: 37963905
DOI: 10.1038/s41598-023-45646-7