Synergic effect of chitosan and dicalcium phosphate on tricalcium silicate-based nanocomposite for root-end dental application

Novel self-setting cements based on tricalcium silicate/(β-tricalcium phosphate/monocalcium phosphate anhydrous)/hydroxypropyl methylcellulose: From hydration mechanism to biological evaluations

Despite the clinical success of tricalcium silicate (TCS)-based materials in endodontics, the inferior handling characteristic, poor anti-washout property and slow setting kinetics hindered their wider applications. To solve these problems, an injectable fast-setting TCS/β-tricalcium phosphate/monocalcium phosphate anhydrous (β-TCP/MCPA) cement was developed for the first time by incorporation of hydroxypropyl methylcellulose (HPMC) and β-TCP/MCPA. The physical-chemical characterization (setting time, anti-washout property, injectability, compressive strength, apatite mineralization and sealing property) of TCS/(β-TCP/MCPA) were conducted. Its hydration mechanism was also investigated. Furthermore, the cytocompatibility and osteogenic/odontogenic differentiation of stem cells isolated from human exfoliated deciduous teeth (SHED) treated with TCS/β-TCP/MCPA were studied. The results showed that HPMC could provide TCS with good anti-washout ability and injectability but slow hydration process. However, β-TCP/MCPA effectively enhanced anti-washout characteristics and reduced setting time due to faster hydration kinetics. TCS/(β-TCP/MCPA) obtained around 90 % of injection rate and high compressive strength whereas excessive additions of β-TCP/MCPA compromised its injectability and compressive strength. TCS/(β-TCP/MCPA) can induce apatite deposition and form a tight marginal sealing at the dentin-cement interface. Additionally, TCS/(β-TCP/MCPA) showed good biocompatibility and promoted osteo/odontogenic differentiation of SHED. In general, our results indicated that TCS/(β-TCP/MCPA) may be particularly promising as an injectable bioactive cements for endodontic treatment.

Chitosan nanoparticle applications in dentistry: a sustainable biopolymer

The epoch of Nano-biomaterials and their application in the field of medicine and dentistry has been long-lived. The application of nanotechnology is extensively used in diagnosis and treatment aspects of oral diseases. The nanomaterials and its structures are being widely involved in the production of medicines and drugs used for the treatment of oral diseases like periodontitis, oral carcinoma, etc. and helps in maintaining the longevity of oral health. Chitosan is a naturally occurring biopolymer derived from chitin which is seen commonly in arthropods. Chitosan nanoparticles are the latest in the trend of nanoparticles used in dentistry and are becoming the most wanted biopolymer for use toward therapeutic interventions. Literature search has also shown that chitosan nanoparticles have anti-tumor effects. This review highlights the various aspects of chitosan nanoparticles and their implications in dentistry.

Chitosan nanocomposite for tissue engineering and regenerative medicine: A review

Regenerative medicine and tissue engineering have emerged as a multidisciplinary promising field in the quest to address the limitations of traditional medical approaches. One of the key aspects of these fields is the development of such types of biomaterials that can mimic the extracellular matrix and provide a conducive environment for tissue regeneration. In this regard, chitosan has played a vital role which is a naturally derived linear bi-poly-aminosaccharide, and has gained significant attention due to its biocompatibility and unique properties. Chitosan possesses many unique physicochemical properties, making it a significant polysaccharide for different applications such as agriculture, nutraceutical, biomedical, food, nutraceutical, packaging, etc. as well as significant material for developing next-generation hydrogel and bio-scaffolds for regenerative medicinal applications. Moreover, chitosan can be easily modified to incorporate desirable properties, such as improved mechanical strength, enhanced biodegradability, and controlled release of bioactive molecules. Blending chitosan with other polymers or incorporating nanoparticles into its matrix further expands its potential in tissue engineering applications. This review summarizes the most recent studies of the last 10 years based on chitosan, blends, and nanocomposites and their application in bone tissue engineering, hard tissue engineering, dental implants, dental tissue engineering, dental fillers, and cartilage tissue engineering.

Fabrication and Characterization of a Nanofast Cement for Dental Restorations

This study was aimed at fabricating and evaluating the physical and bioproperties of nanofast cement (NFC) as a replacement of the MTA. The cement particles were decreased in nanoscale, and zirconium oxide was used as a radiopacifier. The setting time and radiopacity were investigated according to ISO recommendations. Analysis of color, bioactivity, and cytotoxicity was performed using spectroscopy, simulated body fluid (SBF), and MTT assay. The setting time of cement pastes significantly dropped from 65 to 15 min when the particle sizes decreased from 2723 nm to 322 nm. Nanoparticles provide large surface areas and nucleation sites and thereby a higher hydration rate, so they reduced the setting time. Based on the resulting spectroscopy, the specimens did not exhibit clinically noticeable discoloration. Resistance to discoloration may be due to the resistance of zirconium oxide to decomposition. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and infrared spectroscopy (FTIR) examinations of the immersed SBF samples showed apatite formation that was a reason for its suitable bioactivity. The results of cell culture revealed that NFC is nontoxic. This study showed that NFC was more beneficial than MTA in dental restorations.

Enhanced antibacterial activity of calcium silicate-based hybrid cements for bone repair

Calcium silicate cement has attracted much attention for bone defect repair and regeneration due to its osteogenic properties. Biomaterial-associated infections and washout have become a common clinical problem. In order to enhance the antibacterial and washout performance of calcium silicate cement to meet clinical needs, different types of chitosan, including chitosan polysaccharide (CTS), quaternary ammonium chitosan (QTS), and chitosan oligosaccharide (COS), as a liquid phase were added to the calcium silicate powder. The physicochemical properties, in vitro bioactivity, antibacterial efficacy, and osteogenic effects (MG63 cells) of the cement were evaluated. Antibacterial activity was conducted with Gram-negative Escherichia coli (E. coli) and a Gram-positive Staphylococcus aureus (S. aureus) bacteria. The amount of intracellular reactive oxygen species (ROS) produced in the bacteria cultured with the chitosan solution was also detected. The experimental results showed that the chitosan additive did not affect the crystalline phase of calcium silicate cement, but increased the setting time and strength of the cement in a concentration-dependent manner. Within the scope of this study, CTS and QTS solutions with a concentration of not <1 wt% improved the washout resistance of the control cement, while the COS solutions failed to strengthen the cement. When soaked in simulated body fluid (SBF) for 1 day, all cement samples formed apatite spherules. As the soaking time increased, the diametral tensile strength of all cements decreased and the porosity increased. The assays of MG63 cell function showed lower osteogenic activity of osteoblastic cells grown on the surfaces of the chitosan-incorporated cements in comparison with the control cement without chitosan. At the same 1% concentration, compared with QTS and COS cement, CTS cement had lower cell attachment, proliferation, differentiation, and mineralization. Conversely, the CTS cement resulted in the highest bacteriostasis ratio among the three hybrid cements against two bacteria. The ROS production followed the order of CTS > QTS > COS at the same 1% concentration. In conclusion, calcium silicate cement with 1% QTS may be a viable candidate for bone defect repair in view of anti-washout performance, setting time, antibacterial activity, and osteogenic activity shown in this study.

Preclinical assessment of the potential of a 3D chitosan drug delivery system with sodium meloxicam for treating complications following tooth extraction

Current medical healthcare has no sufficient innovative drug delivery formulations for treating patients with alveolar osteitis. This study presents a portion of research conducted to design, fabricate, and characterize systems for the treatment of alveolar osteitis. The results demonstrate that intra-alveolar formulations can be designed to function as drug carriers, facilitate wound dressing, and promote tissue regeneration. Our aim was to design cone-shaped implants made of microcrystalline chitosan filled with sodium meloxicam, i.e., a nonsteroidal anti-inflammatory agent. SEM analysis revealed the porous structure and monophasic characteristic of the formulation. Moreover, textural analysis demonstrated the effect of different factors (shape, hydration, addition of an active substance) on the hardness, springiness and cohesiveness of the studied systems. The active substance was released in a two-phase process. In vitro biocompatibility tests performed according to ISO 10993-5 confirmed the lack of cytotoxicity of the tested formulations. The designed formulations did not stimulate human THP1-XBlue™ monocytes to activate the transcription nuclear factor NF-κB, which ensures that the performed systems do not induce local inflammation. These initial results indicate that the innovative sodium meloxicam release system can improve safety and efficacy in clinical settings.

Facile synthesis of novel calcium silicate hydrated-nylon 6/66 nanocomposites by solution mixing method

In this article a facile and green procedure for the synthesis of novel calcium silicate hydrated-nylon 6/66 nanocomposites is proposed. Calcium silicate hydrate (CSH) was synthesized by a hydrolysis technique assisted by ultrasound and using sodium dodecyl sulphate (SDS) as surfactant. CSH-nylon 6/66 nanocomposites were obtained by a solution mixing method at CSH loadings of 2.5, 25, 50 and 75 weight percent (samples CA, CD, CB and CC, respectively). The synthesis of CSH was confirmed by DRX and ATR-FTIR techniques; the CSH sample presents as mesoporous with a diameter between 3.34 nm and 52.68 nm and an average size of 27.07 nm; the specific surface area of the CSH sample was 343.99 m² g⁻¹. The formation of the CSH-nylon 6/66 nanocomposites was confirmed by ATR-FTIR, SEM, XRD, TGA, DSC and XPS techniques. The crystallization and melting temperatures (T_m and T_c, respectively) of CSH-nylon 6/66 nanocomposites occur at a slightly lower temperatures than those of neat Ny 6/66. These results suggest a slight decrease of the crystallite size and crystallization rate of nylon 6/66. The fusion enthalpy (ΔH_f) decreases with increase in CSH content in nylon 6/66, which can be associated to a good dispersion. The XRD peaks of the nylon 6/66 at 19.99° and 23.77° were displaced at slightly higher values of 2θ with the incorporation of CSH in the polymer forming nanocomposite materials.

In this work it was possible to synthesize novel CSH-nylon 6/66 nanocomposites using a simple and easy methodology such as the solution mixing method and using green solvents like water, formic acid and ethanol.