Effects of surface modification on chlorhexidine release and antimicrobial activity of titanium surfaces

Abstract

Objectives: The aim of this study was to evaluate the ability of modified titanium surfaces to release chlorhexidine (CHX) after periodic CHX exposure and to analyze the antimicrobial activity of CHX release against Streptococcus gordonii.

Materials and Methods: Titanium disks were prepared with four different surface treatments: machined surface (MA), an acid mix of 10% HNO3 and 5% HF (HNF), resorbable blast media (RBM), and sandblasting and acid etching (SLA). The surface roughness of each sample was examined using a confocal laser scanning microscope. Each sample was incubated with whole saliva or phosphate-buffered saline for 2 h. Measurements of CHX release were performed using ultraviolet-visible spectrometry on days 1, 2, and 5 after a 1-min exposure to a 0.5 % chlorhexidine digluconate solution during a 5-day cycle. CHX-releasing experiments were repeated three consecutive times for a total of 15 days. The antimicrobial activity of CHX-treated disks was determined by a disk diffusion test using Streptococcus gordonii.

Results: The CHX-adsorbed titanium surfaces exhibited a short-term release of CHX, and CHX levels dropped rapidly within 3 days after exposure. SLA and RBM released more CHX than HNF and MA. Saliva-coated disks released 5 - 10 times more CHX than non-saliva-coated disks. The disk diffusion test revealed that after CHX uptake, SLA and RBM had greater antimicrobial activity than HNF and MA, specifically in the saliva-coated group.

Conclusion: Within the limitations of this study, chlorhexidine release and uptake were influenced by titanium surface treatment and saliva coating. The results suggest that SLA and RBM might provide effective CHX uptake capacity in the saliva-filled oral cavity.