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Antibacterial and physical properties of calcium-phosphate and calcium-fluoride nanocomposites with chlorhexidine



Lei Cheng, Michael D. Weir, Hockin H. Xu, Alison M. Kraigsley, Nancy Lin, Sheng Lin-Gibson, Xuedong Zhou


Secondary caries limits the longevity of tooth restorations. The replacement of existing restorations accounts for 50-70% of all restorations. Replacement dentistry costs $5 billion in the U.S. annually. The objectives of this study were to (1) develop nanocomposites containing amorphous calcium phosphate (ACP) nanoparticles, calcium fluoride (CaF2) nanoparticles, and chlorhexidine (CHX), and (2) investigate the effects of these nanocomposites on Streptococcus mutans (S. mutans) biofilm formation and lactic acid production for the first time. Four nanocomposites were fabricated with fillers of: Nano ACP; nano ACP + 10% CHX; nano CaF2; nano CaF2 + 10% CHX. A commercial composite with fluoride release, a composite without fluoride release, and a resin-modified glass ionomer were also tested. Compared to commercial composites, ACP nanocomposite had minimal antibacterial property, and CaF2 nanocomposite was moderately antimicrobial. Adding CHX to ACP and CaF2 nanocomposites rendered them strongly antimicrobial. ACP and CaF2 nanocomposites containing CHX maintained a S. mutans media pH of above 6.5, while the pH for commercial composites decreased to 4.2. Nanocomposites with CHX reduced the biofilm acid production and metabolic activity by 10-20 folds, compared to a commercial composite. Colony-forming units of nanocomposites with CHX were orders of magnitude less than that of a commercial composite. Mechanical properties of nanocomposites with CHX were similar to a commercial composite without fluoride nor CHX. In conclusion, the novel nanocomposites could not only release calcium phosphate ions to remineralize the existing lesions, release fluoride to form fluoroapatite to resist acid attacks, but also inhibit biofilm formation and lactic acid production. These antimicrobial, remineralizing, and mechanically-strong nanocomposites may be promising for tooth cavity restorations with anti-caries capabilities.


calcium fluoride, calcium phosphate, caries inhibition, chlorhexidine, dental nanocomposite, stress-bearing, Streptococcus mutans biofilm


Cheng, L. , Weir, M. , Xu, H. , Kraigsley, A. , Lin, N. , Lin-Gibson, S. and Zhou, X. (2012), Antibacterial and physical properties of calcium-phosphate and calcium-fluoride nanocomposites with chlorhexidine, Biomaterials, [online],, (Accessed January 26, 2022)
Created February 5, 2012, Updated October 12, 2021