Experimental synthesis of size-controlled TiO2 nanofillers and their possible use as composites in restorative dentistry

Physicochemical, mechanical and biological properties of nano-calcium silicate-based cements: a systematic review

This systematic review evaluated the effects of nano-sized cement particles on the properties of calcium silicate-based cements (CSCs). Using defined keywords, a literature search was conducted to identify studies that investigated properties of nano-calcium silicate-based cements (NCSCs). A total of 17 studies fulfilled the inclusion criteria. Results indicated that NCSC formulations have favourable physical (setting time, pH and solubility), mechanical (push out bond strength, compressive strength and indentation hardness) and biological (bone regeneration and foreign body reaction) properties compared with commonly used CSCs. However, the characterization and verification for the nano-particle size of NCSCs were deficient in some studies. Furthermore, the nanosizing was not limited to the cement particles and a number of additives were present. In conclusion, the evidence available for the properties of CSC particles in the nano-range is deficient-such properties could be a result of additives which may have enhanced the properties of the material.

[Mechanical and light-activated antibacterial properties of resin filled with Ag-TiO2 nanoparticles]

The poor mechanical property and vulnerability to bacterial infections are the main problems in clinic for dental restoration resins. Based on this problem, the purpose of this study is to synthesize silver-titanium dioxide (Ag-TiO2) nanoparticles with good photocatalytic properties, and add them to the composite resin to improve the mechanical properties and photocatalytic antibacterial capability of the resin. The microstructure and chemical composition of Ag-TiO2 nanoparticles and composite resins were characterized. The results indicated that Ag existed in both metallic and silver oxide state in the Ag-TiO2, and Ag-TiO2 nanoparticles were uniformly dispersed in the resins. The results of mechanical experiments suggested that the mechanical properties of the composite resin were significantly improved due to the incorporation of Ag-TiO2 nanoparticles. The antibacterial results indicated that the Ag-TiO2 nanoparticle-filled composite resins exhibited excellent antibacterial activities under 660 nm light irradiation for 10 min due to the photocatalysis, and the Ag-TiO2 nanoparticle-filled composite resins could also exhibit excellent antibacterial activities after contact with bacteria for 24 h without light irradiation because of the release of Ag ions. In summary, this study provides a new antibacterial idea for the field of dental composite resins.

Evaluation of Micro-Tensile Bond Strength of Fibre Post with Titanium Dioxide Nanoparticles as Fillers in Experimental Dental Composite Resin

Background: The clinical success of post-core restorations is determined by the composite utilized and the strength of the post-core adhesion. The effectiveness of titanium dioxide nanoparticles (TiO₂ NPs) as a multifunctional material with photo-induced activities and better mechanical characteristics are observed as particle size is reduced to under 50 nm. Aim: The purpose of this study is to determine the bond strength of fibre-reinforced composite (FRC) posts with TiO₂ NP as fillers and to compare it with conventional composite resin core material. Materials and Methods: 30 single-rooted mandibular premolars were selected and routine root canal procedures were done. A quantity of 5% TiO₂ NPs were synthesized and added as silanized filler to the experimental composite resin. Post space was prepared and fibre-reinforced composite (FRC) post luting was performed. The specimens were then grouped into the following groups: Group I consisted of the experimental composite resin containing 5% TiO₂ fillers, Group II consisted of core X flow, and Group III consisted of Multicore Flow. All test groups were submitted for thermocycling. After this, the samples were tested for micro tensile bond strength. A stereomicroscope with a magnification of 20× was used to examine the fractured surfaces. The data were analysed using one-way ANOVA and Tukey HSD tests. Results: Statistical analysis revealed that Group I showed the highest mean bond strength value of 35.6180 Mpa. The results obtained with Group III showed the lowest mean bond strength value of 19.4690 Mpa. Adhesive failures were identified by stereomicroscopy of the fractured surfaces. Conclusion: The experimental composite resin comprising 5% TiO₂ NP had a greater bond to the FRC post than other materials tested.

The Potential Application of Green-Synthesized Metal Nanoparticles in Dentistry: A Comprehensive Review

Orodental problems have long been managed using herbal medicine. The development of nanoparticle formulations with herbal medicine has now become a breakthrough in dentistry because the synthesis of biogenic metal nanoparticles (MNPs) using plant extracts can address the drawbacks of herbal treatments. Green production of MNPs such as Ag, Au, and Fe nanoparticles enhanced by plant extracts has been proven to be beneficial in managing numerous orodental disorders, even outperforming traditional materials. Nanostructures are utilized in dental advances and diagnostics. Oral disease prevention medicines, prostheses, and tooth implantation all employ nanoparticles. Nanomaterials can also deliver oral fluid or pharmaceuticals, treating oral cancers and providing a high level of oral healthcare. These are also found in toothpaste, mouthwash, and other dental care products. However, there is a lack of understanding about the safety of nanomaterials, necessitating additional study. Many problems, including medication resistance, might be addressed using nanoparticles produced by green synthesis. This study reviews the green synthesis of MNPs applied in dentistry in recent studies (2010–2021).

Polymeric Dental Nanomaterials: Antimicrobial Action

This review aims to describe and critically analyze studies published over the past four years on the application of polymeric dental nanomaterials as antimicrobial materials in various fields of dentistry. Nanoparticles are promising antimicrobial additives to restoration materials. According to published data, composites based on silver nanoparticles, zinc(II), titanium(IV), magnesium(II), and copper(II) oxide nanoparticles, chitosan nanoparticles, calcium phosphate or fluoride nanoparticles, and nanodiamonds can be used in dental therapy and endodontics. Composites with nanoparticles of hydroxyapatite and bioactive glass proved to be of low efficiency for application in these fields. The materials applicable in orthodontics include nanodiamonds, silver nanoparticles, titanium(IV) and zinc(II) oxide nanoparticles, bioactive glass, and yttrium(III) fluoride nanoparticles. Composites of silver nanoparticles and zinc(II) oxide nanoparticles are used in periodontics, and nanodiamonds and silver, chitosan, and titanium(IV) oxide nanoparticles are employed in dental implantology and dental prosthetics. Composites based on titanium(IV) oxide can also be utilized in maxillofacial surgery to manufacture prostheses. Composites with copper(II) oxide nanoparticles and halloysite nanotubes are promising materials in the field of denture prosthetics. Composites with calcium(II) fluoride or phosphate nanoparticles can be used in therapeutic dentistry for tooth restoration.

The evaluation of healing effect of triclosan and flurbiprofen-loaded nanogels in experimental periodontitis in rats by morphometric analysis

Purpose

To evaluate therapeutic effectiveness of antibacterial triclosan (TCS) and anti-inflammatory flurbiprofen (FLB)-loaded nanogels system in ligature-induced experimental periodontitis in rats.

Methodology

A total of 72 Sprague-Dawley rats were used in this study. Four groups (n = 18 each) were randomly created: Group 1 - neither subjected to experimental periodontitis nor to any treatment; Group 2 - subjected to experimental periodontitis but not treated; Group 3 - subjected to experimental periodontitis and then treated with the developed nanogels; Group 4 - subjected to experimental periodontitis and then placed on a mixture of pure TCS and FLB treatment. The experimental periodontitis was induced on the lower incisors by applying a ligature which was kept for 14 days. Treatment was done for 7 days, and sampling was done at 7, 14, and 28 day of the post-induction experimental period. Morphometric analysis was conducted to assess the clinical outcomes and healing effect.

Results

The morphometric findings showed that the group treated with the developed TCS and FLB-loaded nanogels recovered better and faster than a mixture of pure TCS and FLB. At 28 day of the experimental period, there was no significant difference (p > 0.05) between the baseline control group and the nanogels treated group.

Conclusions

The developed TCS and FLB-loaded nanogels was found to be effective in the treatment of experimental periodontitis in rats. The used experimental periodontitis model was found to be simple and easily reproducible.

Effect of APTES- or MPTS-Conditioned Nanozirconia Fillers on Mechanical Properties of Bis-GMA-Based Resin Composites

To investigate the effects of 3-aminopropyltriethoxysilane (APTES)- or (3-mercaptopropyl)trimethoxysilane (MPTS)-conditioned nanozirconia fillers on the mechanical properties of Bis-GMA-based resin composites. The conditioned fillers were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermodynamic calculations. They were then used to prepare Bis-GMA-based resin composites, whose flexural strength and elastic modulus were evaluated. The Cell Counting Kit-8 (CCK-8) assessed the composites' cytotoxicity. The FTIR spectra of the conditioned fillers showed new absorption bands at 1569 and 1100 cm-1, indicating successful grafting of APTES or MPTS onto nanozirconia. XPS confirmed the Zr-O-Si bonds in the APTES- or MPTS-conditioned fillers at contents of 2.02 and 6.98%, respectively. Thermodynamic calculations reaffirmed the chemical binding between the two silanes and nanozirconia fillers. Composites containing the conditioned nanozirconia fillers had significantly greater flexural strengths (APTES, 121.02 ± 8.31 MPa; MPTS, 132.80 ± 15.80 MPa; control, 94.84 ± 9.28 MPa) and elastic moduli (8.76 ± 0.52, 9.24 ± 0.60, and 7.44 ± 0.83 GPa, respectively) than a control with untreated fillers. The cytotoxicity assay identified no significant cytotoxicity by composites containing the conditioned fillers. Silanes were previously considered to be unable to chemically condition zirconia to bond with resin. Inclusion of APTES- or MPTS-conditioned nanozirconia fillers can improve the mechanical properties of Bis-GMA-based resin composites without obvious cytotoxicity in this study.

Dental Composition Modified with Aryloxyphosphazene Containing Carboxyl Groups

A modifier consisting of the mixture of cyclotriphosphazenes containing 4-allyl-2-methoxyphenoxy and β-carboxyethenylphenoxy moieties was developed for administration with acrylate dental restorative compositions. The synthesized compounds were characterized by ¹H and ¹³C NMR spectroscopy and MALDI-TOF mass spectrometry. The optimal conditions to combine the modifier with the starting dental mixture consisting of bis-GMA and TGM-3 were revealed by differential scanning calorimetry (DSC) method. Properties of the cured modified compositions were evaluated for the compliance with requirements of ISO 4049:2019. It was found that these compositions possess the increased adhesion to dental tissues and cure depth and the decreased water sorption and water solubility. The values of elastic modules, destructive compressive stress and microhardness were also increasing along with the increased content of the modifier in the composition.

Surface Treatment Of Nanozirconia Fillers To Strengthen Dental Bisphenol A-Glycidyl Methacrylate-Based Resin Composites

Purpose

To investigate the effects of nanozirconia fillers conditioned with 10-methacryloyloxydecyl dihydrogen phosphate (MDP) with or without zirconium hydroxide precoating on bending strength, Vickers hardness, and translucence of dental resin composites.

Methods

We obtained nanozirconia fillers coated with different concentrations of Zr(OH)₄ using wet-chemical synthesis. We analyzed coating quality by observing electron-diffraction patterns using transmission electron microscopy. We conditioned zirconia fillers, with or without prior Zr(OH)₄-coating, using MDP-containing primers and evaluated the formation of chemical bonds using nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS). We then performed three-point bending-strength tests, Weibull analysis, Vickers hardness, and translucence-parameter analysis with or without addition of different concentrations of zirconia using untreated zirconia fillers as controls.

Results

We achieved desirable Zr(OH)₄ coating using 5 mmol/L zirconium chloride. NMR and XPS analysis detected stronger Zr–O–P peaks on MDP-conditioned zirconia fillers with prior Zr(OH)₄-coating compared with MDP-conditioned fillers alone, suggesting that MDP bonding with zirconia was enhanced by zirconium hydroxide. Our three-point bending-strength tests revealed that increasing levels of untreated zirconia fillers decreased the three-point bending strength of the resin composites, while MDP-conditioned zirconia fillers with or without prior Zr(OH)₄ coating improved three-point bending strengths. Adding 5 wt% and 7.5 wt% MDP-conditioned zirconia fillers with prior Zr(OH)₄ coating achieved the highest three-point bending strength. Furthermore, addition of zirconia fillers decreased the translucence of silica-based resin composites.

Conclusion

MDP conditioning with prior Zr(OH)₄ coating is recommended for treating nanozirconia fillers of resin composites.