Evaluation of three-dimensional biofilms on antibacterial bonding agents containing novel quaternary ammonium methacrylates.
Antibacterial adhesives are promising to inhibit biofilms and secondary caries. The objectives of this study were to synthesize and incorporate quaternary ammonium methacrylates into adhesives, and investigate the alkyl chain length effects on three-dimensional biofilms adherent on adhesives for the first time. Six quaternary ammonium methacrylates with chain lengths of 3, 6, 9, 12, 16 and 18 were synthesized and incorporated into Scotchbond Multi-Purpose. Streptococcus mutans bacteria were cultured on resin to form biofilms. Confocal laser scanning microscopy was used to measure biofilm thickness, live/dead volumes and live-bacteria percentage vs. distance from resin surface. Biofilm thickness was the greatest for Scotchbond control; it decreased with increasing chain length, reaching a minimum at chain length 16. Live-biofilm volume had a similar trend. Dead-biofilm volume increased with increasing chain length. The adhesive with chain length 9 had 37% live bacteria near resin surface, but close to 100% live bacteria in the biofilm top section. For chain length 16, there were nearly 0% live bacteria throughout the three-dimensional biofilm. In conclusion, strong antibacterial activity was achieved by adding quaternary ammonium into adhesive, with biofilm thickness and live-biofilm volume decreasing as chain length was increased from 3 to 16. Antibacterial adhesives typically only inhibited bacteria close to its surface; however, adhesive with chain length 16 had mostly dead bacteria in the entire three-dimensional biofilm. Antibacterial adhesive with chain length 16 is promising to inhibit biofilms at the margins and combat secondary caries.
1] Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, USA [2] State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Han
H
Zhou
Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, USA.
Michael D
MD
Weir
Biomaterials Group, Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, USA.
Joseph M
JM
Antonucci
Dr. Anthony Volpe Research Center, American Dental Association Foundation, Gaithersburg, USA.
Gary E
GE
Schumacher
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Xue-Dong
XD
Zhou
1] Department of Endodontics, Prosthodontics and Operative Dentistry, University of Maryland Dental School, Baltimore, USA [2] Center for Stem Cell Biology & Regenerative Medicine, University of Maryland School of Medicine, Baltimore, USA [3] Department of Mechanical Engineering, University of Maryland, Baltimore County, USA.
Hockin H K
HH
Xu
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms; D008689:Methacrylates / Q000494:pharmacology*; D018613:Microscopy, Confocal; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D008689:Methacrylates; D000644:Quaternary Ammonium Compounds