Antibacterial fillings
Dental material has been created for "eternal" fillings that kill bacteria
Yulia Vorobyova, Vesti
As you know, tooth enamel is susceptible to plaque growth, which subsequently leads to the destruction of teeth. This is due to the fact that our teeth are covered with a special biofilm – this is a whole conglomerate of microorganisms whose cells are attached to each other. Accumulating, these microorganisms begin to destroy the surface of the tooth, and this leads to the development of gingivitis, caries, periodontal disease and other diseases.
Most harmful microorganisms accumulate not on the "native" surface of the tooth, but in those places that have been "repaired". As a rule, dentists use composite materials for various restorative procedures, on which bacteria feel quite comfortable. In addition, the borders of the healed cavity also remain vulnerable – through them, bacteria penetrate into the tooth tissues.
Thanks to modern technologies, researchers have learned how to create antibacterial dental composites, but they have their drawbacks. The fact is that such materials mainly work on the release of compounds that kill bacteria. Unfortunately, these compounds most often turn out to be toxic to the surrounding tissues, besides they can contribute to the development of resistance of bacteria to treating substances.
And if microorganisms penetrate into the healed cavity, the mechanical strength of the material begins to decrease. Because of this, patients have to go to doctors again: their fillings simply fall out.
To solve all these problems, scientists from the University of Pennsylvania have created a new dental material. It is an antimicrobial compound that not only kills bacteria, but also resists the growth of biofilm from new microorganisms.
The material is based on a resin impregnated with an antibacterial agent based on an organic compound called imidazole.
The authors explain: in some traditional biomaterials, the antimicrobial component is released slowly and washed out over time. But in this case, the resin prevents leaching – this means that organic compounds are not released. They stay in their place and just wait for the appearance of bacteria: microorganisms die only when they come into direct contact with the surface of the tooth covered with a new material.
This property ultimately reduces the resistance of microorganisms. In addition, it is noted that the new material is non-toxic to the surrounding tissue, since it contains a low dose of an antimicrobial agent (high doses are useless, because the concentration of the agent does not decrease over time).
"Dental biomaterials must meet two requirements: firstly, to effectively kill pathogenic microbes, and secondly, to withstand the serious mechanical stress that occurs every time we bite and chew. Many existing materials have a high concentration of antimicrobial agents – they kill a maximum of bacteria, but at the same time weaken the mechanical strength of the tooth and harm its tissues. Meanwhile, our material has no cytotoxicity, is suitable for long service life and does not reduce the mechanical strength of the tooth," says Professor Geelsu Hwang.
Together with his colleagues, he tested the new material, and they showed that the development effectively destroys harmful microorganisms in direct contact with them. This prevents the gradual growth of biofilm: only sticky bacteria that form clusters accumulate on the surface of the tooth. But the control material demonstrated a uniform and constant growth of the biofilm (as shown in the photo on the left).
The team then assessed how easy it is to clean the tooth surface covered with conventional and new material. In the case of the latter, minimal force was needed to remove the biofilm from the surface. In other words, even when you just rinse your mouth with water, part of the biofilm is cleaned off from the place covered with the new material, explains Hwang (in a press release New Dental Material Resists Plaque and Kills Microbes, Penn Dental Team Finds - VM).
But the control material required four times more effort to remove the biofilm from its surface.
According to the authors, their development will become simply irreplaceable in dentistry. Meanwhile, the team plans to create other innovative products to preserve and restore oral health.
More details about the development and properties of the new material are described in an article published in the journal ACS Applied Materials and Interfaces.
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