Built-up sodium alginate/chlorhexidine multilayer coating on dental implants with initiating anti-infection and cyto-compatibility sequentially for soft-tissue sealing.

Soft-tissue sealing at transmucosal sites is very important for preventing the invasion of pathogens and maintaining the long-term stability and function of dental implants. However, the colonization of oral pathogens on the implant surface and surrounding soft tissues can disturb the early establishment of soft-tissue sealing and even induce peri-implant infection. The purpose of this study was to construct two antibacterial coatings with 5 or 10 sodium alginate/chlorhexidine bilayers on titanium surfaces using layer-by-layer self-assembly technology to promote soft-tissue sealing. The corresponding chemical composition, surface topography, wettability and release behaviour were investigated to prove that the resultant coating of sodium alginate and chlorhexidine was coated on the porous titanium surface. In-vitro and in-vivo antibacterial results showed that both prepared coatings inhibited or killed the bacteria on their surfaces and the surrounding areas to prevent plaque biofilm formation, especially the coating with 10 bilayers. Although both coatings inhibited the initial adhesion of fibroblasts, the cytocompatibility gradually improved with coating degradation. More importantly, both coatings achieved cell adhesion and proliferation in an in-vitro bacterial environment and effectively alleviated bacteria-induced subcutaneous inflammation in-vivo. Therefore, this study demonstrated that the multilayered coating could prevent implant-related infections in the initial stage of implant surgery and then improve soft-tissue integration with implant devices.

A homogeneous dopamine-silver nanocomposite coating: striking a balance between the antibacterial ability and cytocompatibility of dental implants.

Silver has been widely used for surface modification to prevent implant-associated infections. However, the inherent cytotoxicity of silver greatly limited the scope of its clinical applications. The construction of surfaces with both good antibacterial properties and favorable cytocompatibility still remains a challenge. In this study, a structurally homogeneous dopamine-silver (DA/Ag) nanocomposite was fabricated on the implant surface to balance the antibacterial activity and cytocompatibility of the implant. The results show that the DA/Ag nanocomposites prepared under the acidic conditions (pH = 4) on the titanium surface are homogeneous with higher Ag+ content, while an obvious core (AgNPs)-shell (PDA) structure is formed under neutral (pH = 7) and alkaline conditions (pH = 10), and the subsequent heat treatment enhanced the stability of PDA-AgNPs nanocomposite coatings on porous titanium. The antibacterial test, cytotoxicity test, hypodermic implantation and osteogenesis test revealed that the homogeneous PDA-AgNPs nanocomposite coating achieved the balance between the antibacterial ability and cytocompatibility, and had the best outcomes for soft tissue healing and bone formation around the implants. This study provides a facile strategy for preparing silver-loaded surfaces with both good antibacterial effect and favorable cytocompatibility, which is expected to further improve the therapeutic efficacy of silver composite-coated dental implants.