AgCa-PLGA submicron particles inhibit the growth and colonization of E. faecalis and P. gingivalis on dentin through infiltration into dentinal tubules.

Eliminating the infection from root canals and periodontal tissues of human teeth as well as the repair of infected periodontal bone has been a great challenge. Poly(lactide-co-glycolide) (PLGA) particles have been used for drug delivery due to their biodegradability, sustained drug release and nontoxic properties. As silver ions (Ag+) exhibit strong antibacterial ability and calcium ions (Ca2+) are essential for hard tissue regeneration, the Ag+ and Ca2+ were encapsulated into the PLGA particles to form AgCa-PLGA submicron particles. The physico-chemical properties, ion release, cytotoxicity, ability to infiltrate dentinal tubules, antibacterial effects against Enterococcus faecalis (E. faecalis) and Porphyromonas gingivalis (P. gingivalis) in either planktonic or biofilm forms on dentin as well as in vitro mineralization ability were investigated. Results showed that Ag+ and Ca2+ were encapsulated into the AgCa-PLGA particles, which could release both Ag+ and Ca2+ over 30 days and exhibited strong antibacterial effects against E. faecalis and P. gingivalis. AgCa-PLGA particles could infiltrate into dentinal tubules by ultrasonic activation and inhibit the colonization of E. faecalis and P. gingivalis on dentin. AgCa-PLGA particles showed no cytotoxicity and induced hydroxyapatite (HA)-like crystal formation. AgCa-PLGA submicron particles could become a biomaterial for both infection control and hard tissue regeneration in dentistry and other related medical areas.