Composites Resist Bacteria and Prevent Recurrent Caries

Dentistry Today


Researchers at Tel Aviv University (TAU) have developed resin-based composites that, when combined with antibacterial nanoassemblies, hinder bacterial growth and viability on dental restorations to prevent recurrent caries.

“Antibiotic resistance is now one of the most pressing healthcare problems facing society, and the development of novel antimicrobial therapeutics and biomedical materials represents an urgent unmet need,” said study leader Lihi Adler-Abramovich, MSc, PhD, of the TAU Maurice and Gabriela Goldschleger School of Dental Medicine.

“When bacteria accumulate on the tooth surface, they ultimately dissolve the hard tissues of the teeth. Recurrent cavities, also known as secondary tooth decay, at the margins of dental restorations results from acid production by cavity-causing bacteria that reside in the restoration-tooth interface,” said Adler-Abramovich. 

Recurrent cavities are a major causative factor for dental restorative material failure and affects about 100 million patients a year at an estimated cost of more than $30 billion, the researchers report.

Amalgam fillings offer some antibacterial properties, but their color, potential toxicity, and lack of adhesion have made new restorative materials based on composite resins a preferable choice of treatment. However, these resins have lacked antimicrobial properties. 

“We’ve developed an enhanced material that is not only aesthetically pleasing and mechanically rigid but is also intrinsically antibacterial due to the incorporation of antibacterial nano-assemblies,” said TAU doctoral student Lee Schnaider.

“Resin composite fillings that display bacterial inhibitory activity have the potential to substantially hinder the development of this widespread oral disease,” said Schnaider.

The researchers are the first to discover the potent antibacterial activity of the self-assembling building block Fmoc-pentafluoro-L-phenylalaine, which comprises both functional and structural subparts. Once the researchers established its antibacterial capabilities, they developed methods for incorporating the nanoassemblies into dental composite restoratives.

Finally, the researchers evaluated the antibacterial capabilities of composite restoratives incorporated with nanostructures as well as their biocompatibility, mechanical strength, and optical properties.

“This work is a good example of the ways in which biophysical nanoscale characteristics affect the development of an enhanced biomedical material on a much larger scale,” said Schnaider. 

“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,” said Adler-Abramovich.

The researchers are now evaluating the antibacterial capabilities of additional minimal self-assembling building blocks and developing methods for their incorporation into various biomedical materials such as wound dressings and tissue scaffolds. 

The study, “Enhanced Nanoassembly-Incorporated Antibacterial Composite Materials,” was published in ACS Applied Materials & Interfaces.

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