WEB Developing Dental Adhesives Reinforced with Green Nanofillers
Dental restoration is an important aspect of health and quality of life. For 150 years, mercury-containing amalgam was widely used in restorative dentistry. However, with the rise of public awareness about environmental and health side-effect, alternative composite materials have become popular, representing almost a quarter of the total restorative dentistry market in recent years. Restorative composite materials are adhered to dentin or enamel by dental adhesives.
Due to the dynamic and hydrated nature of the substrate, adhesion of composite materials to dentin is challenging and produces weaker bonds in comparison to enamel. Weak bonding between restorative materials and dentin causes issues, such as microleakage and secondary damage, ultimately resulting in failure of the restoration. Developing adhesives, that are resistant to degradation in the oral cavity and form stronger bonds to dentin is critical in improving the success rate of dental restorations and enhances patients’ lives by reducing the need for replacements, which subsequently prevents further healthy tissue removal, additional costs and time.
In this study, a novel surface modified crystalline nanocellulose (CNC) is prepared from oxidized bacterial cellulose and characterized using IR and NMR spectroscopy, zeta potential measurement, DSC-MS and elemental analysis. The methacrylate modified CNC is incorporated into an experimental dentin adhesive and the stability of the dispersion is investigated. Stable dispersion of CNC in dental adhesives during the time of application in dentists practice guarantees the reproducibility of the adhesive composition and the outcome of the restoration. The vinyl bearing methacrylate groups on the surface of CNC enable the particles to connect with the crosslinking network of the resin during the curing process and enhance the compatibility between CNC surface and the acrylic based dental resin. The excellent intrinsic mechanical properties of CNC improve the cohesive forces within the bonding layer and the resultant cured adhesives are expected to exhibit superior properties compared to common adhesives. Furthermore, remaining carboxylic acid groups on the surface of CNCs can potentially interact with the calcium ions in the dentin structure and improve the adhesive forces between the composite layer and the dentin. This study opens new avenues to downstream incorporation of plant-based nanoparticles into different dental materials.