Sol-gel-derived calcium silicate cement incorporating collagen and mesoporous bioglass nanoparticles for dental pulp therapy.

OBJECTIVE: Calcium silicate cements (CSCs) are often used in endodontics despite some limitations related to their physical properties and antibacterial efficacy. This study aimed to develop and demonstrate the viability of a series of CSCs that were produced by sol-gel method and further modified with mesoporous bioactive glass nanoparticles (MBGNs) and collagen, for endodontic therapy. METHODS: Calcium silicate (CS) particles and MBGNs were synthesized by the sol-gel method, and their elemental, molecular, and physical microstructure was characterized. Three CSCs were developed by mixing the CS with distilled water (CS+H2O), 10 mg/mL collagen solution (CS+colH2O), and MBGNs (10 %) (CSmbgn+colH2O). The mixing (MT) and setting (ST) times of the CSCs were determined, while the setting reaction was monitored in real-time. Antibacterial efficacy against Enterococcus faecalis (E. faecalis) and regenerative potential on dental pulp stem cells (DPSCs) were also analyzed. RESULTS: The CS+H2O displayed a ST comparable to commercial products, while CSmbgn+colH2O achieved the longest MT of 68 s and the shortest ST of 8 min. All the experimental CSCs inhibited the growth of E. faecalis. Additionally, compared to the control group, CSCs supported cell proliferation and spreading and mineralized matrix production, regardless of their composition. SIGNIFICANCE: Tested CSCs presented potential as candidates for pulp therapy procedures. Future research should investigate the pulp regeneration mechanisms alongside rigorous antibacterial evaluations, preferably with multi-organism biofilms, executed over extended periods.

Developing a bioactive glass coated dental floss: antibacterial and mechanical evaluations.

In the present study, we investigated commercial dental floss coated with chitosan or chitosan + mesoporous bioactive glass nanoparticles (MBGNs) in order to determine the antimicrobial and mechanical properties of the newly fabricated flosses. Whereas these coatings showed notable ability to inhibit growth of both Gram (+) and Gram (-) bacteria after 24 h, the impact was negligible at 3 h. Furthermore, the tensile strength of the floss was improved by the addition of these layers, making it more durable and effective for cleaning between teeth. We therefore propose enhanced investigations of these composites since they demonstrate enormous potential in promoting oral health.

Sol-gel synthesis of lithium doped mesoporous bioactive glass nanoparticles and tricalcium silicate for restorative dentistry: Comparative investigation of physico-chemical structure, antibacterial susceptibility and biocompatibility.

Introduction: The sol-gel method for production of mesoporous bioactive glass nanoparticles (MBGNs) has been adapted to synthesize tricalcium silicate (TCS) particles which, when formulated with other additives, form the gold standard for dentine-pulp complex regeneration. Comparison of TCS and MBGNs obtained by sol-gel method is critical considering the results of the first ever clinical trials of sol-gel BAG as pulpotomy materials in children. Moreover, although lithium (Li) based glass ceramics have been long used as dental prostheses materials, doping of Li ion into MBGNs for targeted dental applications is yet to be investigated. The fact that lithium chloride benefits pulp regeneration in vitro also makes this a worthwhile undertaking. Therefore, this study aimed to synthesize TCS and MBGNs doped with Li by sol-gel method, and perform comparative characterizations of the obtained particles. Methods: TCS particles and MBGNs containing 0%, 5%, 10% and 20% Li were synthesized and particle morphology and chemical structure determined. Powder concentrations of 15mg/10 mL were incubated in artificial saliva (AS), Hank's balanced saline solution (HBSS) and simulated body fluid (SBF), at 37°C for 28 days and pH evolution and apatite formation, monitored. Bactericidal effects against S. aureus and E. coli, as well as possible cytotoxicity against MG63 cells were also evaluated through turbidity measurements. Results: MBGNs were confirmed to be mesoporous spheres ranging in size from 123 nm to 194 nm, while TCS formed irregular nano-structured agglomerates whose size was generally larger and variable. From ICP-OES data, extremely low Li ion incorporation into MBGNs was detected. All particles had an alkalinizing effect on all immersion media, but TCS elevated pH the most. SBF resulted in apatite formation for all particle types as early as 3 days, but TCS appears to be the only particle to form apatite in AS at a similar period. Although all particles had an effect on both bacteria, this was pronounced for undoped MBGNs. Whereas all particles are biocompatible, MBGNs showed better antimicrobial properties while TCS particles were associated with greater bioactivity. Conclusion: Synergizing these effects in dental biomaterials may be a worthwhile undertaking and realistic data on bioactive compounds targeting dental application may be obtained by varying the immersion media.

Sol-gel bioactive glass containing biomaterials for restorative dentistry: A review.

OBJECTIVE: Bioactive glasses (BAGs) have been researched extensively for dentistry due to their favourable biocompatibility and hard tissue bonding ability. However, the specific application of BAGs produced through sol-gel synthesis in restorative dentistry has not been reviewed previously. This review provides a comprehensive account of the principles behind sol-gel derived BAGs and their investigation for dental tissue restoration materials. METHODS: A search for in vitro and in vivo studies was performed using the databases Web of Science®, Medline®, Scopus® and Google Scholar®. Articles published over the past 20 years were selected and data on the BAG composition and morphology was extracted. Analysis of the effect of specific BAG additives on the properties of experimental dental materials was also performed. RESULTS: A majority of BAG particles investigated were spheres ranging in size from 5 nm to ~650 µm. Sol-gel BAGs are mainly applied in the treatment of hypersensitive dentine and for pulp-dentine tissue engineering, while a handful have been used in target drug delivery. BAG fillers are promising additives that result in improved biological properties, antibacterial effects, hardness, acid buffering and remineralization. Unfortunately, some detrimental effects on optical properties have been observed with BAG addition. Additionally, in vivo data, investigations into radiopacity and standardization of test protocols are identified as areas for improvement and further studies. SIGNIFICANCE: Future work should consider the pertinent issues raised in order to improve the quality of available data and expand knowledge in this area of dental biomaterials research and development.

Bioactivity and fluoride release of strontium and fluoride modified Biodentine.

Biodentine™ is a novel tricalcium silicate based material used both as a coronal dentine replacement and in pulp therapy. Its multiple use in sealing perforations, pulp capping and as a temporary restoration arises from its ability to promote dentine formation and to confer an excellent marginal seal. However, there is still room for improvement of this cement as it lacks the anticariogenic effect typically conferred by fluoride ion release as seen in glass ionomer cement based dental materials. Therefore, this study was conducted to investigate the impact of bioactive glass addition to Biodentine™. OBJECTIVE: was to compare the apatite formation capacity, specificity of the apatite type formed and fluoride ion release by Biodentine™ cements that have been modified by three different compositions of bioactive glasses. METHODS: High fluoride, high strontium and high fluoride plus strontium containing bioactive glasses were synthesized, incorporated into Biodentine™ powder and four types of cements prepared. These cements were immersed in phosphate buffered saline solution and incubated for a period of 3 and 24h, 3, 7 and 14 days. Fourier transform infra-red spectroscopy, X-ray diffraction, magic angle spinning nuclear magnetic resonance and fluoride ion release studies were performed. RESULTS: Bioactive glass addition to Biodentine™ led to pronounced formation of apatite. Where the bioactive glass contained fluoride, fluorapatite and fluoride ion release were demonstrated. SIGNIFICANCE: Eliciting fluorapatite formation and fluoride ion release from Biodentine™ is an important development as fluoride is known to have antibacterial and anticariogenic effects.