Physicochemical and Biological Properties of Mg-Doped Calcium Silicate Endodontic Cement

Enhanced bone regeneration via surface functionalization of biphasic calcium phosphate scaffolds with dopamine-modified hyaluronic acid hydrogel or mg-doped calcium silicate

Rapid induction of angiogenesis is crucial for the treatment of large bone defects and accelerating the material-mediated bone defect repair process. In this study, we employed a negative pressure infiltration method to coat the surface of porous BCP scaffolds with dopamine-modified hyaluronic acid (HA-DA) hydrogel and magnesium-doped calcium silicate (Mg-CS). In vitro results demonstrated that HA-DA hydrogel coating with an appropriate degree of dopamine grafting significantly improved the in vitro angiogenic activity of BCP scaffolds without affecting their osteogenic activity. The Mg-CS coating, heat-treated to ensure good combination with the BCP matrix, could sustainably release angiogenic silicon ions and osteogenic magnesium ions. Results from rat cranial defect repair showed that the implanted BCP@HA-DA-2 and BCP@10 Mg-CS scaffolds further accelerated the occurrence and development of neovascularization at the defect site, facilitating new bone formation. Among them, BCP@10 Mg-CS scaffold exhibited the best bone defect repair effect and has the potential for clinical application.

Synthesis, Characterization, and Biological Performances of Magnesium-Substituted Dicalcium Phosphate Anhydrous

Dicalcium phosphate anhydrous (DCPA, CaHPO4) is regarded as an orthopedic material due to its ability to match the generation of new bone to the rate of implant resorption without considering the material's mechanical stability. Additionally, magnesium (Mg) is widely recognized for its essential function in bone metabolism, especially during the initial phases of osteogenesis. Therefore, we explored the influences of Mg ions on DCPA powder, in biological responses, and on the enhancement of osteogenic properties. Mg-DCPA powders with varying substitution levels (0, 3, 5, and 7 mol%) were produced using the co-precipitation method. In the in vitro test, precipitates began to develop on the surface of the Mg-DCPA powders after 7 days. These results indicate that Mg ions in the DCPA powder could enhance the generation of a new apatite phase when subjected to physiological fluids on the surface of the powder. In addition, the osteogenic performance of the DCPA powder was improved by adding Mg ions. The most effective magnesium substitution content in the DCPA powder in order to improve its osteogenic potential was approximately 3 mol%. Consequently, this amount of magnesium in the DCPA powder could control the maintaining time in the implantation operation to produce a new apatite phase.

Sol-Gel Technologies to Obtain Advanced Bioceramics for Dental Therapeutics

The aim of this work is to review the application of bioceramic materials in the context of current regenerative dentistry therapies, focusing on the latest advances in the synthesis of advanced materials using the sol-gel methodology. Chemical synthesis, processing and therapeutic possibilities are discussed in a structured way, according to the three main types of ceramic materials used in regenerative dentistry: bioactive glasses and glass ceramics, calcium phosphates and calcium silicates. The morphology and chemical composition of these bioceramics play a crucial role in their biological properties and effectiveness in dental therapeutics. The goal is to understand their chemical, surface, mechanical and biological properties better and develop strategies to control their pore structure, shape, size and compositions. Over the past decades, bioceramic materials have provided excellent results in a wide variety of clinical applications related to hard tissue repair and regeneration. Characteristics, such as their similarity to the chemical composition of the mineral phase of bones and teeth, as well as the possibilities offered by the advances in nanotechnology, are driving the development of new biomimetic materials that are required in regenerative dentistry. The sol-gel technique is a method for producing synthetic bioceramics with high purity and homogeneity at the molecular scale and to control the surfaces, interfaces and porosity at the nanometric scale. The intrinsic nanoporosity of materials produced by the sol-gel technique correlates with the high specific surface area, reactivity and bioactivity of advanced bioceramics.

Influence of the addition of different metal oxides on physicochemical and biological properties of calcium fluorosilicate/PCL bone cement

Calcium silicate cements have been greatly developed in the last decades through different approaches. Among these approaches, the inclusion of antibacterial agents or addition of metal oxides. Herein, calcium silicate cement containing fluorine (CFS) was developed from sodium fluorosilicate precursor for the first time using chemical perception method. Afterwards, metal oxide Bi2O3 or MgO or ZrO2 was individually mixed with CFS powder and blended together using Polycaprolactone polymer (PCL). The cement mixtures were characterized using DSC, XRD, FTIR and SEM/EDX to determine the effect of metal oxide on the pure CFS. Furthermore, mechanical, antibacterial and cell viability properties were evaluated for the developed CFS mixture cements. Moreover, these CFS mixture cements were implanted in male Wistar rats to determine the effect of metal oxides on the rate of bone reformation. The findings of physicochemical and morphological characterization showed no remarkable effects on the pure CFS after mixing with each metal oxide. However, enhanced compressive strengths (up to 104.07N/cm2), antibacterial activity and cell viability (up to 96%) were achieved for the CFS cement mixtures. Finally, the in vivo studies confirmed the biocompatibility of the CFS cement mixtures and especially those mixed with Bi2O3 or ZrO2. Therefore, this study supports that CFS blends with Bi2O3 or ZrO2 can be novel promising cementing materials for bone restoration.

Polysaccharide-bioceramic composites for bone tissue engineering: A review

Limitations associated with conventional bone substitutes such as autografts, increasing demand for bone grafts, and growing elderly population worldwide necessitate development of unique materials as bone graft substitutes. Bone tissue engineering (BTE) would ensure therapy advancement, efficiency, and cost-effective treatment modalities of bone defects. One way of engineering bone tissue scaffolds by mimicking natural bone tissue composed of organic and inorganic phases is to utilize polysaccharide-bioceramic hybrid composites. Polysaccharides are abundant in nature, and present in human body. Biominerals, like hydroxyapatite are present in natural bone and some of them possess osteoconductive and osteoinductive properties. Ion doped bioceramics could substitute protein-based biosignal molecules to achieve osteogenesis, vasculogenesis, angiogenesis, and stress shielding. This review is a systemic summary on properties, advantages, and limitations of polysaccharide-bioceramic/ion doped bioceramic composites along with their recent advancements in BTE.

Mechanism of action of Bioactive Endodontic Materials

A continuous search for bioactive materials capable of supporting the replacement of damaged pulp tissue, with effective sealing potential and biocompatibility, has represented the attention of studies over the last decades. This study involves a narrative review of the literature developed by searching representative research in PUBMED/MEDLINE and searches in textbooks associated with the mechanism of action of bioactive materials (calcium hydroxide, mineral trioxide aggregate (MTA), and calcium silicate cements). The reflective analysis of the particularities of the chemical elements of these materials, considering the tissue and antibacterial mechanism of action, allows a better understanding of the characteristics and similarities in their tissue responses. Calcium hydroxide paste remains the antibacterial substance of choice as intracanal dressing for the treatment of root canal system infections. Calcium silicate cements, including MTA, show a favorable biological response with the stimulation of mineralized tissue deposition in sealed areas when in contact with connective tissue. This is due to the similarity between the chemical elements, especially ionic dissociation, the potential stimulation of enzymes in tissues, and the contribution towards an alkaline environment due to the pH of these materials. The behavior of bioactive materials, especially MTA and the new calcium silicate cements in the biological sealing activity, has been shown to be effective. Contemporary endodontics has access to bioactive materials with similar properties, which can stimulate a biological seal in lateral and furcation root perforations, root-end fillings and root fillings, pulp capping, pulpotomy, apexification, and regenerative endodontic procedures, in addition to other clinical conditions.

Bioactive Inorganic Materials for Dental Applications: A Narrative Review

Over time, much attention has been given to the use of bioceramics for biomedical applications; however, the recent trend has been gaining traction to apply these materials for dental restorations. The bioceramics (mainly bioactive) are exceptionally biocompatible and possess excellent bioactive and biological properties due to their similar chemical composition to human hard tissues. However, concern has been noticed related to their mechanical properties. All dental materials based on bioactive materials must be biocompatible, long-lasting, mechanically strong enough to bear the masticatory and functional load, wear-resistant, easily manipulated, and implanted. This review article presents the basic structure, properties, and dental applications of different bioactive materials i.e., amorphous calcium phosphate, hydroxyapatite, tri-calcium phosphate, mono-calcium phosphate, calcium silicate, and bioactive glass. The advantageous properties and limitations of these materials are also discussed. In the end, future directions and proposals are given to improve the physical and mechanical properties of bioactive materials-based dental materials.

Fabrication of functional and nano-biocomposite scaffolds using strontium-doped bredigite nanoparticles/polycaprolactone/poly lactic acid via 3D printing for bone regeneration

Bone tissue engineering is a field to manufacture scaffolds for bone defects that cannot repair without medical interventions. Ceramic nanoparticles such as bredigite have importance roles in bone regeneration. We synthesized a novel strontium (Sr) doped bredigite (Bre) nanoparticles (BreSr) and then developed new nanocomposite scaffolds using polycaprolactone (PCL), poly lactic acid (PLA) by the 3D-printing technique. Novel functional nanoparticles were synthesized and characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS: map). The nanoparticles were uniformly distributed in the polymer matrix composites. The 3D- printed scaffolds were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), attenuated total reflection-fourier transform infrared (ATR-FTIR), degradation rate porosity, mechanical tests, apatite formation and cell culture. Degradation rate and mechanical strength were increased in the PLA/PCL/Bre-5%Sr nanocopmposite scaffolds.. Hydroxyapatite crystals were also created on the scaffold surface in the bioactivity test. The scaffolds supported viability and proliferation of human osteoblasts. Gene expression and calcium deposition in the samples containing nanoparticles indicated statistical different than the scaffolds without nanoparticles. The nanocomposite scaffolds were implanted into the critical-sized calvarial defects in rat for 3 months. The scaffolds containing Bre-Sr ceramic nanoparticles exhibited the best potential to regenerate bone tissue.

Morphological and Chemical Analysis of Different Types of Calcium Silicate-Based Cements

Objectives. Particle size and shape can influence the properties of materials. However, to improve the physicochemical and biological properties of mineral trioxide aggregate (MTA), silicate-based hydraulic cements were introduced. This study aimed to evaluate and compare the major constituents and crystalline structures along with the surface morphology of different types of calcium silicate-based cement (CSC). Materials and Methods. Six different types of CSC (white Portland cement, white ProRoot MTA, white MTA Angelus, Biodentine, and Endosequence, both putty and paste) were used in this study. Five samples of each material were analyzed in both uncured and cured cement using scanning electron microscopy/energy-dispersive X-ray (SEM/EDX), X-ray diffraction (XRD), and Fourier transform-infrared spectroscopy (FTIR). Results. SEM analysis showed that the surfaces of all materials consisted of particle sizes ranging from 0.194 μm to approximately 51.82 μm. The basic elements found in both uncured and cured cement of all tested materials using EDX were carbon, calcium, silicon, and oxygen. A difference was observed in the presence or absence of magnesium, aluminum, bismuth, zirconium, and tantalum. XRD showed that all tested materials were composed mainly of tricalcium silicate and dicalcium silicate, which are the main components of Portland cement. FTIR analysis showed aromatic rings, phosphine PH, alkyl halides, and alcohol O-H groups in all tested materials but at different wavenumbers. Conclusions. The different types of CSCs tested in this study were primarily modified types of Portland cement with the addition of radiopacifiers. ProRoot MTA and MTA Angelus contained bismuth oxide, Biodentine contains zirconium oxide, whereas Endosequence root repair materials (both putty and paste) contained zirconium oxide and tantalum oxide. Endosequence root repair materials showed smaller particle sizes than the other groups. White PC had the most irregular and large particle sizes. CSC had a smaller particle size, except for MTA Angelus. Clinical Relevance. The composition of CSC has a direct influence on the properties of these cements, which may affect the clinical outcome of the treatment.