Biobased adhesives derived from zein corn protein and tannic acid for dental applications

Modern commercial dental adhesives can take on many forms such as cements, glues, and coatings. These adhesive varieties, typically made with bisphenol A glycidyl dimethacrylate (bisGMA), are commonly used in a wide array of oral applications. BisGMA is a skin, respiratory, and ocular irritant, as well as a carcinogen. Despite the apparent toxicity to both patient and practitioner, this compound produces the best adhesion for dental applications. Nontoxic alternatives, while safer, currently cannot outperform, or even match, the current compounds employed today. We have previously shown that a zein-tannic acid adhesive has had great success in saltwater environments while being nontoxic and biobased. Our adhesive’s active components consist of zein, a protein derived from corn, and tannic acid, a plant-derived phenolic compound. Due to this formulation’s success in an aqueous environment, it is an ideal candidate to apply and optimize in dental applications. We have applied our adhesive formulation in oral conditions, which consist of a pH-restricted and fouled environment covered in biofilms, resulting in more adhesion adversity compared to our prior saltwater applications. Even with these constraining factors, we have seen adhesion that varies as a function of tannic acid and zein concentrations and with additional inorganic filler compounds. While still in the early stages of optimization this adhesive shows promise in oral applications.