Antibacterial and Cytocompatible: Combining Silver Nitrate with Strontium Acetate Increases the Therapeutic Window

Osteoblast cell behavior on polyetheretherketone dental implant surfaces treated with different grit size aluminum oxide particles: An in vitro analysis

STATEMENT OF PROBLEM

The hydrophobic and bioinert nature of polyetheretherketone (PEEK) implants needs to be addressed for successful osseointegration.

PURPOSE

The purpose of this in vitro study was to evaluate the osteoblast cell behavior on PEEK implant surfaces treated with airborne-particle abrasion using different grit size aluminum oxide (Al2O3) particles.

MATERIAL AND METHODS

Disk-shaped specimens (n=96) were prepared from medical grade PEEK rods and were distributed into 4 groups (n=24) of untreated PEEK (PEEK 0), airborne-particle abrasion using 50-μm Al2O3 particles (PEEK 50), airborne-particle abrasion using 110-μm Al2O3 particles (PEEK 110), and airborne-particle abrasion using 150-μm Al2O3 particles (PEEK 150). The surface characteristics were assessed using water contact angle (WCA) measurements and scanning electron microscopy (SEM). MG-63 osteoblast cells were cultured, and the biocompatibility of PEEK was assessed using a CellTiter-blue cell viability assay and florescence staining at day 1, 3, and 7. The specimens were stained with Alizarin red to assess the osteoblast cell differentiation on day 10 and 14. The Levene test was used to test the homogeneity of variances. One-way and Welch ANOVA with post hoc corrections were used to assess the overall statistical significance of differences among the groups (α=.05).

RESULTS

The lowest mean WCA was demonstrated in PEEK 150 (49.25 ±5.51) and the highest in PEEK 0 (89.14 ±4.24) (P<.001). SEM images of PEEK 150 illustrated a more complex structure with a large area of globular outcroppings throughout the surface. PEEK 150 showed the highest cell metabolic activity at each time point with florescence staining showing a substantial cell confluence at day 3 and 7. Although PEEK 150 did not show a significant increase in cell proliferation, the number of cells attached was significantly higher than other groups (P<.05). PEEK 110 and 150 also showed a substantial increase in the extent of mineralization.

CONCLUSIONS

Airborne-particle abrasion using moderate Al2O3 grit size (110- or 150-μm) improved the hydrophilicity and osteoblast cell behavior on PEEK implants.

Effectiveness of strontium/silver-based titanium surface coatings in improving antibacterial and osteogenic implant characteristics: a systematic review of in-vitro studies

Introduction: Due to the high incidence of implant failures, dual functionalization of titanium surfaces with antibacterial and osteogenic agents, like silver (Ag) and strontium (Sr), has gained significant attention in recent years. However, so far, the combined antibacterial and osteoinductive effectiveness of Ag/Sr-based titanium surface coatings has only been analyzed in individual studies. Methods: This systematic review aims to evaluate the existing scientific literature regarding the PICOS question "Does dual incorporation of strontium/silver enhances the osteogenic and anti-bacterial characteristics of Ti surfaces in vitro?". As a result of a web-based search adhering to the PRISMA Guidelines using three electronic databases (PubMed, Scopus, and Web of Science) until March 31, 2023, a total of 69 publications were identified as potentially relevant and 17 of which were considered appropriate for inclusion into this review. Results and Discussion: In all included publications, the use of Sr/Ag combination showed enhanced osteogenic and antibacterial effects, either alone or in combination with other agents. Moreover, the combination of Sr and Ag shows potential to synergistically enhance these effects. Nevertheless, further studies need to validate these findings under clinically more relevant conditions and evaluate the mechanism of antimicrobial and osteogenic activity of Sr/Ag combination.

Silica-based silver nanocomposite 80S/Ag as Aggregatibacter actinomycetemcomitans inhibitor and its in vitro bioactivity

Background/purpose

As a commonly-found pathogen in periodontal disease, Aggregatibacter actinomycetemcomitans has been reported with several antibiotic resistance. Thus, to develop an alternative and protective therapy for A. actinomycetemcomitans infections is urgently needed in dentistry. In this study, we sought to synthesize a silica-based material to deliver silver nanoparticles for antibacterial purposes. Also, the bioactivities were examined via analyzing the formation of hydroxyapatite.

Materials and methods

The 80S/Ag powders were prepared by the evaporation-induced self-assembly method, with Si, Ca, P, and Ag composition ratios of 80, 15, 5, and 1/5/10 (mole percentage), respectively. The nitrogen adsorption-desorption isotherms, transmission electron microscope, selected area electron diffraction, and Fourier transform infrared spectroscopy were conducted for textural analyses. The disk diffusion test was carried out against A. actinomycetemcomitans strain ATCC 29523. In vitro bioactivity assessment involved soaking 80S/Ag membrane powders in acellular simulated body fluid.

Results

We successfully developed a material consisting of Si, Ca, P, and Ag, namely the 80S/Ag. In the antibacterial testing, the 80S/Ag demonstrated antibacterial activity against the commonly-found oral pathogen, A. actinomycetemcomitans, with a long-lasting effect for 168h. The formation of hydroxyapatite in simulated body fluid highlighted the characteristic of dentine remineralization for the 80S/Ag. The increased pH values after immersion in simulated body fluid would help neutralize the acidic oral environment.

Conclusion

Our results indicate that 80S/Ag possesses remarkable antibacterial properties, hydroxyapatite formation, and increased pH values after immersion in simulated body fluid, supporting the potential therapeutic application of 80S/Ag for treating periodontal disease.