Plaque and Microbes Defeated by New Dental Material

Dentistry Today


Plaque can grow on composite materials just as it grows on enamel. Yet a new dental material tethered with an antimicrobial compound can kill bacteria and resist biofilm growth, according to the University of Pennsylvania. It also is effective with minimal toxicity to the surrounding tissue, unlike some drug-infused materials, containing a low dose of the antimicrobial agent that only kills the bacteria that come into contact with it.  

“Dental biomaterials such as these need to achieve two goals. First, they should kill pathogenic microbes effectively, and, second, they need to withstand severe mechanical stress, as happens when we bite and chew,” said Geelsu Hwang, a research assistant professor at the university’s School of Dental Medicine.

“Many products need large amounts of antimicrobial agents to maximize killing efficacy, which can weaken the mechanical properties and be toxic to tissues, but we showed that this material has outstanding mechanical properties and long-lasting antibiofilm activities without cytotoxicity,” said Hwang.  

The material comprises a resin embedded with the antibacterial agent imidazolium. Some traditional biomaterials slowly release a drug, while this material is non-leachable, only killing the microbes that touch it and reducing the likelihood of antimicrobial resistance. The researchers tested the material’s ability to kill microbes, prevent the growth of biofilms, and withstand mechanical stress.

The material proved effective in killing bacterial cells on contact, severely disrupting the ability of biofilms to grow on its surface. Only negligible amounts of biofilm matrix, which holds clusters of bacteria together, were able to accumulate on the experimental material. A control composite material, meanwhile, showed a steady accumulation of sticky biofilm matrix.

Next, the researchers assessed how much shear force was required to remove the biofilm from the experimental material. The smallest force removed almost all of the biofilm from the new material, but even a force four times as strong was incapable of removing the biofilm from the control composite material.

“The force equivalent to taking a drink of water could easily remove the biofilm from this material,” Hwang said. 

Funded by Dentsply Sirona, the study, “Nonleachable Imidazolium-Incorporated Composite for Disruption of Bacterial Clustering, Exopolysaccharide-Matrix Assembly, and Enhanced Biofilm Removal,” was published by ACS Applied Materials & Interfaces.

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