Nanodentistry: Every Small Particle Counts

Man is creature who goes on creating new technologies and tries his best to make it the most efficient one. Nanotechnology is the concept that if one goes to the ground level of a thing, he has lot many possibilities of bringing up new things from a basic part. “NANOTECHNOLOGY” has been a new revolution in the field of dentistry. This revolution can help us to relieve our patients from the oral health problems and many such issues. A more generalized description of nanotechnology was subsequently established by the National Nanotechnology Initiative, which defines nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100nm. Due to the widen interest of nanotechnology in the field of dentistry, there have been an emergence of a new field called Nanodentistry.

In last few decades, it’s been witnessed that there has been great proliferation in all the fields of medicine. The conceptual underpinnings of nanotechnologies were first laid out in 1959 by the noble prize winning physicist Richard Feynman in his lecture, “There’s plenty of room at the bottom”. In his historic lecture, he concluded saying, “this is a development which I think cannot be avoided”. Along with his work in theoretical physics, Feynman has been credited with pioneering the field of quantum computing and introducing the concept of nanotechnology. Every coin has two sides, significant and non-significant. Similarly, Nanotechnology has its own advantages and disadvantages. Nano describes ‘DWARF’ but still this nanotechnology has a vast potential now- a-days. On other hand, it also depends on social issues of public acceptance, ethics and yes, majorly on Human safety; so as to provide the high quality of dental care. Nanotechnology has its own misuses too.

NANODENTISTRY APPROACHES

Bottom-up approaches: Assemblance of small components to the complex ones.

Top-down approaches: Creation of small structures by using bigger ones in guiding their assembly.

Nanodentistry in Bottom-up approaches: 

Nanorobotic Dentifrice (dentifrobots)

Dentifrobots in the form of mouthwash or toothpaste left on the occlusal surface of teeth can clean organic residues by moving throughout the supragingival and subgingival surfaces, metabolizing trapped organic matter into harmless and odourless vapors and performing continuous calculus debridement.

These nanorobots can move as fast as 1-10 μ /s and are safely self-deactivated when they are swallowed.

Inducing anesthesia

Application of nanotechnology can be used to induce anesthesia. The gingiva of the patients is instilled with a colloidal suspension containing millions of active, analgesic, micron-sized dental robots that respond to input supplied by the dentist. After contacting the surface of crown or mucosa, the ambulating nanorobots reach the pulp via the gingiva sulcus, lamina propia and dentinal tubules, guided by chemical gradient, temperature differentials controlled by the dentist. Once in the pulp, they shut down all sensation by establishing control over nerve-impulse traffic in any tooth that requires treatment. After completion of treatment, they restore sensation thereby providing patient with anxiety-free and needless comfort. Anesthesia is fast acting, and reversible, with no side effects or complications associated with its use.

Hypersensitivity Cure

Hypersensitivity may be caused by changes in the pressure transmitted hydrodynamically to the pulp. The dentinal tubules of a hypersensitive tooth have twice the diameter and eight times the surface density of those in nonsensitive teeth. Dental nanorobots could selectively and precisely occlude selected tubules in minutes using native logical materials, offering patients a quick and permanent cure.

Major Tooth Repair

Nanodental techniques for major tooth repair may evolve through several stages of technological development, first using genetic engineering, tissue engineering and tissue regeneration, and later involving the growth of whole new teeth in vitro and their installation. Ultimately, the nanorobotic manufacture and installation of a biologically autologous whole-replacement tooth that includes both mineral and cellular components— that is, complete dentition replacement therapy—should become feasible within the time and economic constraints of a typical office visit, through the use of an affordable desktop manufacturing facility, which would fabricate the new tooth, in the dentist’s office.
Nanodentistry could also play a vital role in natural tooth maintenance.

Therapeutic aid in oral diseases
Drug delivery
Nanotechnology is opening new therapeutic opportunities for many agents that cannot be used effectively as conventional oral formulations because of their poor bioavailability. In some cases, reformulation of a drug with smaller particle size may improve oral bioavailability. Nanoparticles formulations provide protection for agents susceptible to degradation or denaturation in regions of harsh pH, and also prolong the duration of exposure of a drug by increasing retention of the formulation through bioadhesion.Ideally, all these systems would improve the stability, absorption, and therapeutic concentration of the drug within the target tissue, as well as permit reproducible and long-term release of the drug at the target site.

Gene Therapy

Gene therapy is a recently introduced method for treatment or prevention of genetic disorders by correcting defective genes responsible for disease development based on the delivery of repaired genes or the replacement of incorrect ones.

Three main types of gene delivery systems have been described: viral vectors, nonviral vectors (in the form of particles such as nanoparticles, liposomes, or dendrimers), and the direct injection of genetic materials into tissues using so-called gene guns. Applications of nanotechnological tools in human gene therapy has been reviewed widely by Davis, who described nonviral vectors based on nanoparticles (usually 50-500 nm in size) that were already tested to transport plasmid DNA. He emphasized that nanotechnology in gene therapy would be applied to replace the currently used viral vectors by potentially less immunogenic nanosize gene carriers. So delivery of repaired genes or the replacements of incorrect genes are fields in which nanoscale objects could be introduced successfully.

Nanodentistry as top down approaches:

Nanocomposites

Inorganic fillers in nanodimensions are diffused homogenously without any accumulation in the matrix in the artificial teeth produced from nanocomposites. Studies have shown that nanocomposite artificial teeth are more durable than acrylic teeth and microfill composite teeth and have a higher resistance to abrasion.

Nano Light-Curing Glass Ionomer Restorative

This blends Nanotechnology initially developed for Filtek TM Supreme Universal Restorative with fluoralumino silicate technology.

Nano Impression Materials

Traditional vinylpolysiloxanes have incorporated nanofillers, which produce a distinctive material with improved flow, enhanced hydrophilic properties and superior detail precision.

Nano-Composite Denture Teeth

Conventional denture teeth have their own inherent disadvantage. Porcelain is highly wear resistant, but is brittle, lacks bonding ability to the denture base, and is not easy to polish. Acrylic on the other hand is to adjust, but undergo undue wear.

Nanocomposite denture teeth are made of Polymethylmethacrylate(PMMA) and homogeneously distributed nanofillers.

Nanosolutions

They provide unique and dispersible nanoparticle, which can be used in bonding agents (trade name: Adper, Single Bond Plus, Adhesive Single Bond). A new flowable composite (Dentiflow) has an acceptable shear bond strength for bonding orthodontic brackets and can be used without liquid to reduce the bonding procedure time while maintaining an acceptable bond strength. Ceram-X MonoTM; a nanocomposite was reported to have a lesser bond strength compared with traditional orthodontic composite but was within clinically acceptable range for bonding.

Nanoencapsulation

Targeted release systems that encompass nanocapsules including novel vaccines, antibiotics and drug delivery with reduced side effects have been developed by the South West Research Institute. An example is an attempt to generate effective and satisfactory drug delivery system for the treatment of periodontal diseases by producing nanocapsules impregnated with triclosan. Application of triclosan into the test area alleviated inflammation.

Plasma Laser application

Application of nanosized titania particle emulsion on human skin followed by laser irradiation, leads to the disintegration of the particles along with other results like:

• Shock waves
• Microabrasionof hard tissues
• Stimulus to produce collagen

Prosthetic Implants

Nanotechnology would aid in the development of surfaces with definite topography and chemical composition leading to predictable tissue-integration.

Tissue differentiation into definite lineage will accurately determine the nature of peri-implant tissues. In addition, antibiotics or growth factors may be incorporated as CaP coating is placed on Ti implants. eg: NanotiteTM Nano-Coated Implant.

Nanoneedles

Suture needles incorporating nano-sized stainless steel crystals have been developed (trade name: Sandrik Bioline, RK91 needles, AB Sandrik Sweden). Nano tweezers are also under development, which will make cell surgery possible in the near future.

Bone replacement materials

Nanotechnology aims to emulate the natural structure present on bone, which is composed of organic compounds (mainly collagen) and reinforced with inorganic ones. Nanocrystals show a loose microstructure, with nanopores situated between the crystals. The surfaces of the pores are modified such that they adsorbed protein, due to the addition of silica molecules. Bone defects can be treated using the hydroxyapatite nanoparticles.

Challenges faced by Nanotechnology

• Precise positioning and manufacture of nanoscale parts.
• Cost-effective nanorobot mass manufacturing methods.
• Synchronization of numerous independent nanorobots.
• Biocompatibility concern.
• Financing and tactical concerns.
• Inadequate assimilation of clinical research.
• Social issues of public acceptance, ethics, regulation and human safety.

Nanotechnology is foreseen to change health care in a fundamental way. It forms the basis of novel methods for disease diagnosis and prevention. It will be useful in therapeutic selection tailored to the patients profile and will come in handy in drug delivery and gene therapy.

Ms Kanchan Dhake

(1st BDS)