Many fillings only last about five to 10 years before they need to be replaced, often because of new cavities that crop up around their edges, according to the National Institute of Dental and Craniofacial Research. This happens in part because the adhesive that seals the filling to the tooth breaks down over time, leaving tiny gaps that cavity-causing bacteria can infiltrate.
Aided by artificial intelligence (AI), a cross-disciplinary team of experts in materials science and data science at the University of Kansas set out to tackle this problem by designing a dental adhesive with bacteria-fighting properties.
Led by Candan Tamerler, PhD, and Paulette Spencer, DDS, PhD, both professors of bioengineering and mechanical engineering, the researchers looked to nature for an antibacterial solution. They landed on a class of molecules called antimicrobial peptides, which all organisms produce as a first line of defense against harmful bacteria.
The researchers modified these peptides by adding chemical “spacers,” or short strings of amino acids, which in turn linked the peptides to methacrylate, a common ingredient in dental adhesives.
The spacers were designed to keep the antimicrobial peptide firmly attached to the methacrylate, yet distanced enough to keep the peptide’s structure and its bacteria-killing abilities intact. The researchers then designed and tested two versions of peptide-laden adhesives, one with a short spacer, and another longer one.
In lab experiments, adhesives with the shorter spacer more effectively killed Streptococcus mutans, the bacterial species responsible for tooth decay. To better understand this result, the researchers used AI-based computing to characterize the effect of varying spacer lengths on the structure and flexibility of antimicrobial peptides. The peptides with the shorter spacer maintained a more natural shape, explaining their superior antimicrobial activity.
“With these AI-based analyses, we can predict material designs that optimize a peptide’s biological activity,” said Tamerler, adding that the approach could be used to develop a variety of dental and medical materials that incorporate peptides and other biologically active molecules. “Using AI for rational, iterative design of materials could revolutionize the field of dentistry.”
The study, “Antimicrobial Peptide-Polymer Conjugates for Dentistry,” was published by ACS Applied Polymer Materials.