Chlorhexidine-based Nanoparticles as an Antimicrobial Coating for Dental Implants

Objective:

The aim was to investigate the applicability of chlorhexidine-hexametaphosphate (CHX-HMP) NPs as a coating for titanium dental implants.

Method:

Aqueous solutions (10 mM) of chlorhexidine digluconate and sodium hexametaphosphate were combined while stirring, resulting in precipitation of CHX-HMP NPs. Commercially pure grade II titanium substrates were immersed in the rapidly stirred colloidal suspension for 30 s, followed by 10 s rinsing in deionised water. Some specimens were then incubated in whole human saliva for 2 h to deposit a salivary pellicle.

NP size and surface distribution were investigated using transmission electron microscopy (TEM), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Release of CHX from NP-coated substrates was monitored using ultraviolet spectrophotometry (UV). Antimicrobial efficacy against Streptococcus gordonii and Porphyromonas gingivalis was investigated.

Result:

CHX-HMP NPs had diameter ̴50nm (TEM) and adhered to titanium surfaces, forming porous, micrometer-sized aggregates, surrounded by bare titanium (AFM, SEM). CHX was released from these surfaces into water for over 60 days at a steady rate of 0.2 nmol/day; however, when a pellicle was applied, the CHX release rate reduced to 0.06 nmol/day. Adhesion and proliferation of S. gordonii or P. gingivalis on the NP-coated surfaces were inhibited within 24 h.

Conclusion:

CHX-HMP NPs were used to coat clinically relevant titanium substrates. The NP-coated surfaces exhibited antimicrobial efficacy against S. gordonii and P. gingivalis, showing the potential for the CHX-HMP NPs to protect implants against oral bacterial infections.