Getting a filling isn't always the end of a tooth's cavity problems. Sometimes, bacteria is able to get down between the filling and the surface of the tooth, causing another cavity to occur. A new antibacterial dental restorative material, however, could help keep that from happening.

It should be noted that this isn't the first bacteria-killing filling material we've seen. Most of the others, however, work by slowly releasing antibacterial compounds into the mouth – these chemicals can be toxic to the adjacent tissue, plus they may contribute to antibacterial resistance. Additionally, the fillings will presumably start running out of the compounds at some point.

With these limitations in mind, a team from Israel's Tel Aviv University started with a dental resin composite, then added a modified amino acid known as fmoc-pentafluoro-L-phenylalanine. The latter remains within the resin, and has a nanostructure that ruptures the outer membranes of cavity-causing bacteria as they come into contact with it – thus killing them.

Additionally, the antibacterial resin is "aesthetically-pleasing" in appearance (unlike the old-school mercury fillings), plus it's mechanically rigid. By contrast, the mechanical strength of some previously-developed antibacterial restorative materials was compromised by the presence of the compounds within them.

"The minimal nature of the antibacterial building block, along with its high purity, low cost, ease of embedment within resin-based materials and biocompatibility, allows for the easy scale-up of this approach toward the development of clinically available enhanced antibacterial resin composite restoratives," says co-lead scientist Dr. Lihi Adler-Abramovich.

A paper on the research, which was also led by doctoral student Lee Schnaider, was recently published in the journal ACS Applied Materials & Interfaces.

And for another example of an antibacterial filling material that doesn't leach compounds into the mouth, check out the resin that was developed in 2017 at the University of Pennsylvania.