- The term "nano" refers to the nanometer, 1 millionth of a millimeter--nanotechnology generally deals with structures 100 nanometers and below. While it is hoped that we can eventually build working technology such as machines and electronics at this scale, problems arise because various properties of physics change as we get smaller. Simple moving machines at the nano scale have been demonstrated, but we are far from assembling molecular machines. Nano-particles are being applied in various industries, including medicine, due to various properties such as increased resistance to wear and the killing of bacteria, but there are worries due to the unknown consequences to the environment and human health.
- Two types of methods exist for working with nanotechnology, each approaching the problem from a different direction. Bottom-up methods use various processes to induce structures to self-assemble at the scale desired. Top-down methods build a structure at a scale easily worked at to, in turn, build another structure at a smaller, unreachable scale.
- Humans have been using nanotechnology for a long time without realizing it. The processes of making steel, vulcanizing rubber and sharpening a razor all rely on manipulations of nano-particles. Richard Zsigmondy studied nano-materials in the early 20th century, and later discoveries culminated in ideas presented by Richard Feynman in a lecture called "Plenty of Room at the Bottom" in 1959, where he explored the implications of matter manipulation. Applications began in the 1980s with the invention of the scanning tunneling microscope and the discovery of carbon nano-tubes and fullerenes. In 2000, the U.S. government founded the National Nanotechnology Initiative to direct nanotechnological development.
- Current applications in dentistry include tooth sealants and fillers that use nano-particles to retain strength, luster, and resist wear. Silver nano-particles limit the growth of bacteria; thus, fillers and orthodontics using them naturally retard the growth of bacteria leading to decay.
- It is hoped that we will be able to use nanotechnology to rebuild bone that has receded over time after a tooth has been extracted, making implants an option for far longer than currently possible. A longer-term hope is that self-replicating nano-machines could repair and rebuild damaged teeth completely.
