“Science means constantly walking a tightrope between blind faith and curiosity; between expertise and creativity; between bias and openness; between experience and epiphany; between ambition and passion; and between arrogance and conviction - in short, between an old today and a new tomorrow”, - Heinrich Rohrer. The concepts that gave an idea of nanotechnology were first discussed in 1959 by renowned physicist Richard Feynman in his talk ‘There's Plenty of Room at the Bottom’, in which he described the possibility of generating new materials via direct manipulation of atoms. The term 'nano-technology' was first used by Norio Taniguchi in 1974.
The word ‘nano’, is derived from the Greek word ‘nannos’ meaning ‘dwarf’, is a prefix that literally denotes to 1 billionth of a physical size. 1nm = 1 billionth of a meter. To put this size in to perspective put a marble next to earth. The concept of nanomedicine was 1st described by Robert A. Freitas Jr in the year 1993, after observing the advancements in nanotechnology and its potential implications in various fields. In the past 20 years various theoretical predictions have been made based on the potential applications for nanotechnology in dentistry, with guarded optimism.
Albert Einstein once said, “I have no special talent. I am only passionately curious”. For past many years People around the world have been harnessing their curiosity and transforming it in to an inquiry which has led to the process of scientific methodology that has eventually led to an unprecedented growth in research in the area of nanoscience including nanomedicine and nanodentistry. Nanodentistry is nothing but the maintenance of comprehensive oral health by employing nanomaterials, biotechnology, including tissue engineering and ultimately, dental nanorobotics. In short, the nanotechnology will help in diagnosis, treatment, as well as maintenance of any dental diseases. The newer potential treatment opportunities in dentistry may include, painless local anesthesia, renaturalization of dentition, permanent treatment for dentinal hypersensitivity, complete orthodontic realignments treatment during a single dental visit , covalently or chemically bonded diamondized enamel and dentine for the treatment of genetically or environmentally inherited diseases of dental hard tissues, and continuous oral health maintenance using mechanical dentifrobots (Chen et al., 2005).
Nanorobots will be the forerunner in complete dentition replacement therapy. In simple terms, the nanobots would be able to manufacture and deliver a biologically autologous tooth for a replacement of missing tooth and all these can be done during a single dental visit, making the whole process of tooth rehabilitation more time efficient for both dentist and patients, which in turn lead to more patient compliance. The fear of injections into the oral cavity or drills is the main reasons most people are afraid of dentistry or avoid their dental treatment. But with the help of nanobots, dentist will be able to instill a colloidal suspension containing millions of active analgesic micron-sized dental nanorobot 'particles' on the patient's gingiva. Once these particles come in contact with the surface of mucosa or the crown, the pacing nanorobots reach the dentin by migrating into the gingival sulcus and passing painlessly through the lamina propria or the 1 to 3-micron thick layer of loose tissue at the cementodentinal junction or to the free nerve endings.
Various studies have shown that teeth with hypersensitivity have surface density of dentinal tubules eight times higher and twice as large diameter as non-sensitive teeth. Freitas in 2005 with various other authors stated that Reconstructive dental nanorobots, using native biological materials, could selectively and precisely occlude specific tubules within minutes, offering patients a quick and permanent cure from a life long suffering of dentinal hypersensitivity. For the cosmetic restoration due to loss of tooth structure the conventional methods usually deal with replacing upper enamel layers with covalently bonded artificial materials such as sapphire or diamond. These materials are highly susceptible to fracture, Jayraman in 2004 stated that incorporation of carbon nanotubes in to these materials can render them more fracture resistant, making a material more durable and long-lasting.
Kumar and Vijayalakshmi in 2006 concluded their study saying that when nanofillers are incorporated into vinylpolysiloxanes impression material it produces a unique siloxane impression material that has a better flow, improved hydrophilic properties, and enhanced precision details when compared to conventional impression material. Bone is a natural nanostructure that is composed of organic compounds (mainly collagen) and reinforced with inorganic ones, like calcium and phosphate. Nanotechnology aims to mimic this very same natural structure for orthopedic and dental applications and, more particularly, for the development of nanobone in a lab. The loose structure of nanocrystals with nanospores situated between them can be modified so that it can adsorb proteins due to the incorporation of silica molecule. This hydroxyapatite nanoparticle material than can be used to treat bone defects.
When implant placement is considered as a therapeutic option the major concern of a dental practitioner is osseointegration, and the main determining factors for successful osseointegration are surface contact area and surface topography of an implant surface. But with the help of nanotechnology bone growth and increased predictability can be effectively expedited with implant therapy. Studies have shown that, the addition of nanoscale deposits of hydroxyapatite and calcium phosphate on implant surface creates a more complex implant surface for osteoblast formation. Extensive research has been carried out for optimization of implant surface, and resultant new implants are superior to the conventional implant. The newer implants are more acceptable, as they have integrated nanocoatings resembling biological materials to the tissues.
In the treatment of localized periodontitis nanobots can be used as an agent to deliver the drug precisely to the involved site. The materials that are used for this purpose is a core which is hollow from within or a nanotube. The drugs than can be incorporated in to these hollow structures, they are made up of biodegradable polymer, this allows the drug to released precisely at the active disease site, leading to more substantivity of a drug. Sub-occlusally present nanobots delivered either through tooth paste or a mouth wash can help in the treatment of halitosis by acting against the pathogenic bacteria, the nanobots transform the metabolites that are responsible for foul odor produced by these bacteria in to odorless vapors and perform continuous debridement of the tooth surface.
Charles Darwin said: “It is the long history of humankind that those who learned to collaborate and improvise most effectively have prevailed”. Even in dentistry, when we take a holistic approach to treating a disease, making our approach multidisciplinary, we can provide better treatment for patients.
As a wise man said, “No one can whistle a symphony. It takes a whole orchestra to play it”.
The visions described here may sound unlikely, implausible, or even heretic. Yet, the theoretical and applied research to turn them into reality is progressing rapidly. When it comes to making these visions in to a reality we may be bound by the limitation of the technology of our time, which is not yet fully developed to bring nanotechnology in to everyday life.
There are certain limitations to put nanotechnology into a routine dental practice such as, design and installation cost of these nanobots, maintenance, social acceptance, human safety, ethical issues, and biocompatibility. But as they say these truly are the days of ‘miracle and wonder’. Bright future lies ahead in dental field, but we shall all have to work very long and very hard to make it come to pass.