Effects of Quaternary Ammonium Chain Length on Antibacterial Bonding Agents

• Published in: Journal of dental research 2013-10, Vol.92 (10), p.932-938
• Main Authors: Li, F., Weir, M.D., Xu, H.H.K.
• Format: Article
• Language: English
• Subjects: Adhesives; Ammonium; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Antimicrobial agents; Bacteria; Bacterial Adhesion - drug effects; Biofilms; Biofilms - drug effects; Bond strength; Cell Survival - drug effects; Colonization; Colony Count, Microbial; Cytotoxicity; Dentin; Dentin-Bonding Agents - chemistry; Dentin-Bonding Agents - pharmacology; Fibroblasts; Fibroblasts - drug effects; Fourier transforms; Materials Testing; Minimum inhibitory concentration; Odontoblasts - drug effects; Quaternary Ammonium Compounds - chemistry; Quaternary Ammonium Compounds - pharmacology; Research Reports; Resin Cements - chemistry; Resin Cements - pharmacology; Resins; Streptococcus infections; Streptococcus mutans; Streptococcus mutans - drug effects; Studies
• ISSN: 0022-0345; 1544-0591; 1544-0591
• DOI: 10.1177/0022034513502053

The objectives of this study were to synthesize new quaternary ammonium methacrylates (QAMs) with systematically varied alkyl chain lengths (CL) and to investigate, for the first time, the CL effects on antibacterial efficacy, cytotoxicity, and dentin bond strength of bonding agents. QAMs were synthesized with CL of 3 to 18 and incorporated into Scotchbond Multi-Purpose (SBMP) bonding agent. The cured resins were inoculated with Streptococcus mutans. Bacterial early attachment was investigated at 4 hrs. Biofilm colony-forming units (CFU) were measured after 2 days. With CL increasing from 3 to 16, the minimum inhibitory concentration and minimum bactericidal concentration were decreased by 5 orders of magnitude. Incorporating QAMs into SBMP reduced bacterial early attachment, with the least colonization at CL = 16. Biofilm CFU for CL = 16 was 4 log lower than SBMP control (p < .05). All groups had similar dentin bond strengths (p > .1). The new antibacterial materials had fibroblast/odontoblast viability similar to that of commercial controls. In conclusion, increasing the chain length of new QAMs in bonding agents greatly increased the antibacterial efficacy. A reduction in Streptococcus mutans biofilm CFU by 4 log could be achieved, without compromising bond strength and cytotoxicity. New QAM-containing bonding agents are promising for a wide range of restorations to inhibit biofilms.