New Dental Filling Material Fights Bacteria

New approaches to antimicrobial treatment are taking shape not only in doctors’ offices and hospitals, but in dental practices too. To this end, researchers from the University of Pennsylvania say they’ve developed a novel dental material that is infused with an antimicrobial compound.

Good oral hygiene involves the use of dental care products with fluoride, drinking fluoridated water, regular visits to the dentist, limiting alcohol intake, and avoiding tobacco products. According to the Centers for Disease Control and Prevention (CDC), oral disease such as cavities, gum disease, and oral cancer—which arises from poor oral hygiene—leads to an estimated $113 billion dollars in dental care costs each year in the United States. More than 80% of adults have at least 1 cavity by the age of 34. Cavities are caused by bacterial biofilms (aka, dental plaque) that produce acids that break down tooth enamel. When left untreated, this decay can lead to tooth loss and a severe infection of the gums called gingivitis. Gingivitis can cause a more serious condition called periodontitis, which can lead to bone and tissue loss around the teeth. These oral infections can then also spread to other parts of the body and cause severe infections.

To treat the decay, dentists will fill the cleaned-out, previously decayed, section of the tooth. However, the materials used for traditional fillings are also susceptible to the bacterial biofilms, which can impact neighboring teeth.

Now, researchers from the University of Pennsylvania and Dentsply Sirona, a dental equipment maker, have developed a novel material for use in restorative dental procedures that offers the added benefit of having antibacterial properties. In a new study, published in the journal ACS Applied Materials and Interfaces, the authors present their evaluation of the material, which is comprised of a resin embedded with the antibacterial agent imidazolium. After testing the material with the oral pathogen Streptococcus mutans, the investigators found that the new antimicrobial composite can kill bacteria and resist biofilm growth.

"Dental biomaterials such as these need to achieve 2 goals,” explained study author Geelsu Hwang, PhD, in a recent press release, explaining how the composite fights bacteria without affecting gums and surrounding tissue. “First, they should kill pathogenic microbes effectively, and, second, they need to withstand severe mechanical stress, as happens when we bite and chew. Many products need large amounts of anti-microbial 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."

In addition, the antimicrobial agent in the composite does not leach and only kills the bacteria that touch it, which the study’s authors say will limit the development of antimicrobial resistance.

Oral health problems can be more common in those with chronic conditions such as heart disease, diabetes, arthritis, hepatitis C, obesity, HIV, or other conditions that weaken the immune system and so efforts to combat bacteria in the mouth may be helpful for individuals with these conditions.