Regulating Oral Biofilm from Cariogenic State to Non-Cariogenic State via Novel Combination of Bioactive Therapeutic Composite and Gene-Knockout.

The objectives were to investigate a novel combination of gene-knockout with antimicrobial dimethylaminohexadecyl methacrylate (DMAHDM) composite in regulating oral biofilm from a cariogenic state toward a non-cariogenic state. A tri-species biofilm model included cariogenic (), and non-cariogenic () and (). Biofilm colony-forming-units (CFUs), lactic acid and polysaccharide production were measured. TaqMan real-time-polymerase-chain reaction was used to determine the percentage of each species in biofilm. The gene-knockout for with DMAHDM composite reduced biofilm CFU by five logs, compared to control ( < 0.05). Using parent , an overwhelming percentage of 68.99% and 69.00% existed in biofilms on commercial composite and 0% DMAHDM composite, respectively. In sharp contrast, with a combination of knockout and DMAHDM composite, the cariogenic percentage in biofilm was reduced to only 6.33%. Meanwhile, the non-cariogenic + percentage was increased to 93.67%. Therefore, combining -knockout with bioactive and therapeutic dental composite achieved the greatest reduction in , and the greatest increase in non-cariogenic species, thereby yielding the least lactic acid-production. This novel method is promising to obtain wide applications to regulate biofilms and inhibit dental caries.