Researchers at the Chemistry and Biochemistry Department at National Chung Cheng University in Taiwan has published a paper in Nanotechnology demonstrating the use of gold nanoparticles in occluding dental tubules. Researchers have found that sensitive teeth have an increased number of dentinal tubules (35.6% compared to 9.3%) and are wider in diameter (0.83 µm compared to 0.43 µm) than the dentinal tubules of non sensitive dentine. The Chinese researchers have demonstrated that this tubules can be blocked with the aid of gold nanoparticles.
An interesting aspect of gold at the nanoscale is that gold nanoparticles exhibit a clear size-dependent trend: the smaller gold nanoparticles get, the lower is their melting point. This deviation of the melting temperature from the bulk value becomes dramatic at a size around 5 nm in diameter, ultimately reaching well under 50% of the bulk melting point of gold.One of the methods of closing sub-micron sized dentinal tubules explored by Dr. Chris Wang and his team involved the sintering of highly concentrated gold nanoparticles that were brushed into the exposed open ends of dentinal tubules. Laser irradiation induced the photofusion of gold nanoparticles via photothermal conversion.