ANTIMICROBIAL EFFECTS OF FORMABLE GELATINOUS HYDROXYAPATITE-CALCIUM SILICATE NANOCOMPOSITES FOR BIOMEDICAL APPLICATIONS.

The recently developed GEMOSIL, a nanocomposite material composed of gelatinous hydroxyapatite (HAP-GEL) and animosaline by pozzolanic crosslinking, provides a potentially improved alternative to current endodontic cements. The mechanical performance of fully dried GEMOSIL approximated that of cortical bone. In its pre-set form, the moldable cement solidified in approximately 5 minutes when submerged in water, primarily due to the pozzolanic crosslinking. The purpose of this study was to test if adding chlorhexidine to Ca(OH)2 during the formation of this material could provide enhanced antimicrobial effects. Four zones of inhibition were formed using GEMOSIL, GEMOSIL ^CHX, Mineral Trioxide Aggregate (MTA; Tulsa Dentsply), and Chlorhexidene as a control. Each material was prepared into disc samples (6.2mm x 0.85mm; 8 per material). The Enterococcus faecalis and Streptococcus mutans strains were cultured at 37 °C under anaerobic conditions. Bacterial suspensions were evenly distributed on a blood-agar plate surface. The MTA/GEMOSIL/GEMOSIL ^CHX /Chlorhexidine discs were placed on the inoculated blood-agar plates which were immediately incubated at 37 o C for 18-24 hours under aerobic conditions. Results showed that the Chlorhexidine and GEMOSIL ^CHX provided a similar antimicrobial effect to Enterococcus faecalis, while GEMOSIL and MTA did not. All four materials showed similar effects to Streptococcus mutans. In combination with previous reports showing osteogenesis of GEMOSIL, the GEMOSIL ^CHX may be applicable to both orthopedic and endodontic cements. [ABSTRACT FROM AUTHOR]