Dental Piezoelectric Composites with Antimicrobial, Mineralization and Tissue Regeneration Functionalities

Dental materials with antimicrobial, mineralization and tissue regeneration functionalities have been proposed in recent years. These treatments are aimed to improve dental treatments, prevent oral infections, and regenerate oral tissues. The aim of this study is to develop dental piezoelectric composites offering these multiple functionalities. In this work, we evaluated the antibacterial, antifungal, and mineralization effects of novel piezoelectric composites. Piezoelectric composite samples were fabricated mixing dental resins with barium titanate (BaTiO3) nanoparticles (piezoelectric filler). A commercial composite was used as control. The physical, mechanical, electromechanical properties of the composite were evaluated according to ISO-ADM standards. The antimicrobial effects of the composites were systematically evaluated for different concentrations of piezoelectric filler and charge magnitude. Samples were simultaneously subjected to a liquid culture of pathogenic microorganisms (S. mutans and C.albicans) and repetitive mechanical loading to activate the electrical charges. Cell-viability, metabolism and biofilm biomass were evaluated. Live/dead fluorescence was also conducted. For mineralization tests, the samples were submerged in calcium saturated media (simulated body fluid - SBF). The quantity and chemistry of the formed minerals was evaluated for different concentrations of piezoelectric filler and charge magnitude. For the first time, our results showed the antimicrobial effects of piezoelectric composites. After the biofilm challenge, we observed a reduction in the biofilm biomass (80%), metabolic activities (90%) and an increase in the number of dead cells compared to the control group for both bacteria. Similar results were obtained for fungi species and different concentration of BaTiO3 and charge magnitude. The antimicrobial mechanism was also revealed. The piezoelectric composite showed remineralization capabilities evidenced by the formation of calcium phosphate layers with thicknesses ranging 5–23 μm for mechanically stimulated composites in 7 days. A novel piezoelectric dental composite with antimicrobial, and mineralization effects was developed. A significant reduction in the biofilm biomass, metabolic activity and viable bacteria was observe for the piezo-composites compared to control. The best antimicrobial effect was found for lower amounts of BaTiO3 (<10%) and small electrical charges (<3.2 pC/cm2). The incorporation of piezoelectric fillers in the dental–adhesive composites prevented the bacterial penetration on the bonded interface ex-vivo. Piezoelectric biomaterials could be utilized in other medical fields where the eradication of biofilms on implants is a challenge.Download : Download high-res image (142KB)Download : Download full-size image