NANOTECHNOLOGY

PRESENTED BY:-

SRUTHI K NAIRPOST GRADUATE STUDENT

CONTENTS INTRODUCTION HISTORY OF NANOTECHNOLOGY TECHNIQUES IN NANOTECHNOLOGY NANOMATERIALS NANODENTISTRY AND ITS APPLICATION NANOROBOTICS NANODIAGNOSTICS NANOMATERIALS NANOMATERIALS FOR PERIODONTAL CONCLUSION REFERENCES

INTRODUCTION Science is undergoing yet another change in

helping mankind enter a new era, the era of nanotechnology.

‘Nanotechnology’ includes structures ranging in the size of 100 nanometers or smaller in at least one dimension and other developing materials or devices within that size, -: fibers that are less than 100 nm diameter, films less than 100 nm in thickness, nanoholes, and composites.

‘Nano’ is derived from the Greek word ‘vaos’, meaning ‘dwarf ’.

Is a prefix literally refers to 1 billionth of a physical size.

According to defintion of the ‘National Nanotechnology Initiative ‘

direct manipulation of materials at the nanoscale General :- “Science Of The Small” The central idea of nanotechnology is to employ

individual atoms and molecules to construct functional structures.

FOREFATHERS OF NANOTECHNOLOGY

The late Nobel Prize winning scientst Richard P. Feynman established the potential of nanosize devices in 1959.

proposed using machine tools to make smaller machine tools, which, in turn, would be used to make still smaller machine tools, and so on all the way down to the molecular level.

He suggested that such nanomachines, nanorobots and nanodevices ultimately could be used to develop a wide range of atomically precise microscopic instrumentation and manufacturing tools.

Feynman argued that these tools could be applied to produce vast quantities of ultrasmall computers and various microscale and nanoscale robots. He concluded that this is “a development which I think cannot be avoided.”

The vision of nanotechnology was born.

K Eric Drexler independently used the term ‘nanotechnology’ in 1986. Humans have been using nanotechnology for a long time without realizing it. The processes of making steel, vulcanizing rubber and sharpening a dental instrument, all rely on manipulations of nanoparticles.

Richard Zsigmondy studied nanomaterials in the early 20th century.

Applications began in the 1980s with the invention of the scanning tunneling microscope and the discovery of carbon nanotubes.

TECHNIQUES OF NANOTECHNOLOGY

Top-down Technique Bottom-up Technique

TOP-DOWN TECHNIQUE In this technique smaller devices are created by

using larger ones to direct their assembly. So, small features are made by starting with larger materials patterning and carving down to make nanoscale structures in precise patterns.

Complex structures containing hundreds of millions of precisely positioned nanostructures can be fabricated.

Materials are reduced to the nanoscale and can suddenly show very different properties, enabling unique applications.

As the size of system decreases there is increase in ratio of surface area to volume and number of physical phenomena becomes noticeably pronounced

BOTTOM-UP TECHNIQUE In this technique smaller components are

arranged into more complex assembly.

This begins by designing and synthesizing custom made molecules that have the ability to self-assemble or self-organize into higher order mesoscale or macroscale structures.

Modern synthetic chemistry has reached the point where it is possible to prepare small molecules to almost any structure.

These methods are used today to manufacture a wide variety of useful chemicals such as pharmaceuticals or commercial polymers. Such bottom- up approaches are much cheaper than top-down methods, but could potentially be overwhelmed as the size and complexity of the desired assembly increases.

NANO MATERIALSRichard W. Siegel

› Nanoparticles › Nanopores › Nanotubes › Nanorods › Nanospheres › Nanofibers › Nanoshells › Dendrimers › Nanorings › Nanocapsules › Quantum dots › Dendrimers

Inorganic nanoparticles (Semiconductor nanoparticles, Metal

nanoparticles, Metal oxide nanoparticles, Silica nanoparticles,Polyoxometalates,Gold nanocrystals)

NANODENTISTRY AND ITS APPLICATIONS

Nanodentistry will make possible the maintenance of comprehensive oral health by employing nanomaterials, biotechnology, including tissue engineering, and ultimately, dental nanorobotics. Nanodentistry includes:

Nanorobotics Nanodiagnostics Nanomaterials

NANOROBOTICS

Nanorobot 'an artificially fabricated objects able to freely diffuse in the human body and interact with specific cell at the molecular level by itself.’

Nanorobotics is the technology of creating machines or robots at or close to the microscopic scale of nanometers.

Nanites, Nanoant

COMPOSITION OF NANOROBOTS

• DIAMETER:-0.5-2MICRONS, PARTS WITH DIMENSIONS 1-10nm• CARBON-PRINCIPAL ELEMENT

• THE EXTERIOR CARBON DIAMONOID STRUCTURE• SPIDER LIKE BODY.

• ON BOARD NANO COMPUTERS.

MECHANISM OF ACTIONo The powering of nanorobots can be done by metabolizing

local glucose, oxygen and externally supplied acoustic energy.

o controlled by onboard computers capable of performing around 1000 or more computations per second.

o Communication with the device can be achieved by broadcast type acoustic signaling. A navigational network installed in the body provides high positional accuracy to all passing nanorobots and keep track of the various devices in the body.

o Nanorobots are able to distinguish between different cell types by checking their surface antigens.

o Building nanorobots involves sensors, actuators, control, power, communications and interfacial signals across spatial scales and between organic/inorganic as well as biotic/ abiotic systems.

o When the task of the nanorobots is completed, they can be retrieved by allowing them to effuse themselves via the usual human excretory channels. They can also be removed by active scavenger systems 

APPLICATION IN DENTISTRY AND PERIODONTOLOGY

1. Local Anaesthesia

COLLOIDAL SUSPENSION

Pulp.On board

nano computer

Dentin,gingival sulcus

dentinal tubules 1-4micrones

the analgesic dental nanorobots may be commanded by the dentist to shut down all sensitivity in any particular tooth that requires treatment. When on the hand-held controller display, the selected tooth immediately becomes numb. After the oral procedures completed, the dentist orders the nanorobots to restore all sensation, to relinquish control of nerve traffic and to egress, followed by aspiration.

Nanorobotic analgesics offer greater patient comfort and reduced anxiety, no needles, greater selectivity, and controllability of the analgesic effect, fast and completely reversible switchable action and avoidance of most side effects and complications.

2. Dental Biomimetics The most interesting venue for speculation on

the nanorestoration of tooth structures is that of nanotechnology mimicking processes that occur in nature (biomimetics), such as the formation of dental enamel.

Through an affordable desktop manufacturing facility, fabrication of a new tooth in the dentist's office within the time & economic constraints of a typical dental office visit, complete dentition replacement therapy will become feasible soon.

Chen et al utilizing nanotechnology simulated the natural biomineralization process to create the dental enamel, using highly organized microarchitectural units of nanorod-like calcium hydroxyapatite crystals arranged roughly parallel to each other

3. Dental Durability and Cosmetics Tooth durability and appearance may be

improved by replacing upper enamel layers with covalently bonded artificial materials, such as sapphire or diamond, which have 20 to 100 times the hardness and failure strength of natural enamel, or contemporary ceramic veneers as well as good biocompatibility.

Pure sapphire and diamond are brittle and prone to fracture resistant as part of a nanostructure composite material that possibly includes embedded carbon nanotubes.

4. Orthodontic Treatment Orthodontic nanorobots could directly manipulate the

periodontal tissues, including gingivae, periodontal ligament, cementum and alveolar bone, allowing rapid and painless tooth straightening, rotating and vertical repositioning within minutes to hours. This is in contrast to current molar-uprighting techniques, which require weeks or months to complete.

5. Renaturalization Procedures

Dentition renaturalization procedures may become a popular addition to the future dental practice, made possible through esthetic dentistry.

patients who desire to have their old dental amalgams excavated and their teeth remanufactured with native biological materials.

Full coronal renaturalization procedures in which all fillings and crowns are removed, and the affected teeth are remanufactured to become indistinguishable from the original teeth .

6. Dentirobots

Subocclusal dwelling nanorobotics dentifrice delivered by mouthwash or toothpaste could patrol all Supragingival and subgingival surfaces atleast once a day, metabolizing trapped organic matter into harmless and odorless vapors and performing continuous calculus debridement.

small dentifrobots [1-10 micon], crawling at 1-10 microns/sec, would be inexpensive, purely mechanical devices, that would safely deactivate themselves if swallowed, and would be programmed with strict occlusal avoidance protocol.

Properly configured dentifrobots could identify and destroy pathogenic bacteria residing in the plaque and elsewhere, while allowing the ~500 species of harmless oral microflora to flourish in a healthy ecosystem.

Dentifrobots also would provide a continuous barrier to halitosis, since bacterial petrification is the central metabolic process involved in oral malodor .

7. Hypersensitivity Cure Dentin hypersensitivity may be caused by

changes in pressure transmitted hydrodynamically to the pulp.

Natural hypersensitive teeth have eight times higher surface density of dentinal tubules and diameter with twice as large than nonsensitive teeth.

Reconstructive dental nanorobots, using native biological materials, could selectively and precisely occlude specific tubules within minutes, offering patients a quick and permanent cure.

NANODIAGNOSTICS1. Nanoscale Cantilevers Flexible beams resembling a row of diving

boards. Built using Semiconductor lithographic techniquees that can be engineered to bind to molecules associated with cancer.

2. Nanopores These are tiny holes that allow DNA to pass through one strand at a time. They will make DNA sequencing more efficient.

3. Nanotubes First described by Iijima in 1991 Sheets of graphene that can be rolled into

hollow cylinders These are carbon rods about half the

diameter of a molecule of DNA that not only can detect the presence of altered genes but also may help researchers pinpoint the exact location of those changes.

4. Quantum Dots These are nanomaterials that glow very brightly

when illuminated by ultraviolet light. They can be coated with a material that makes

the dots attach specifically to the molecules to be tracked.

Quantum dots bind themselves to proteins unique to cancer cells, literally bringing tumours to light.

5. Nano Electromechanical Systems (NEMS) Nanotechnology based NEMS biosensors

that exhibit –sensitivity and specificity diagnose even a small molecular change.

They convert (bio) chemical to electrical signal.

6. Lab-on-a-chip methods Lab-on-a-chip (LOC) is a device which

integrates several laboratory functions on a single chip. LOCs deal with the handling of extremely small fluid volumes down to less than pico liters.

LOC methodologies have been used to assess the levels of interleukin-1beta (IL-1beta), C- reactive protein (CRP), and matrix metalloproteinase-8 (MMP-8) in whole saliva- diagnosing and categorizing the severity and extent of periodontitis.

Multi plexing modality Sensing large number of different

biomolecules simultaneously in real time.

Useful in diagnosis of oral cancer and diabetes mellitus and for detection of bacteria, fungi and viruses.

NANO MATERIALS1. Nanocomposites Discrete nanoparticles are

homogeneously distributed in resins or coatings to produce nanocomposites. The nanofiller used includes an aluminosilicate powder having a mean particle size of 80 mm and a 1:4 M ratio of alumina to silica and a refractive index of 1.508

2.Nanosolution Nanosolutions produce unique and dispersible

nanoparticles, which can be added to various solvents, paints & polymers in which they are dispersed homogenously.

Nano technology in bonding agents ensures homogeneity and that the adhesive is perfectly mixed everytime

Impression Material Impression material is available with

nanotechnology application. Nanofillers are integrated in

vinylpolysiloxanes, producing a unique addition of siloxane impression material. The material has better flow, improved hydrophilic properties and enhanced detail precision.

Nanoneedles

Scientists have achieved a subtle surgical operation on a parti cular living cell, by means of a needle that is just a few billionths of a meter wide.

Nanoneedles are nanosized stain less steel needles, which will make cell surgery possi ble in the near future.

Nanoneedles can be used to deliver molecules, -nucleic acids, proteins, or other chemicals to the nucleus, or may even be used to carry out cell surgery.

Using the nanoneedle approach, we can get to a very specific location within the nucleus; this is the key advantage of this method.

Nanotweezers The Danish research group (Nanohand) has

developed nano tweezers, which can be used for both imaging and manipulation of nanosized objects to make cell surgery feasible in the near future.

These nanotweezer probes consist of two wires tapered consecutively through a nanopipette and kept electrically isolated.

Nanomaterials for Periodontal Drug Delivery

Drugs can be incorporated into nano spheres composed of a biodegradable polymer, and this allows for timed release of the drug as the nanospheres degrade facilitating site-specific drug delivery

Recently triclosan loaded nanoparticles prepared using poly (d, l lactide coglycolide), poly (d,l lactide) and cellulose acetate phthalate reduction of inflammation.

Tetracycline incorporated into microspheres is available as Arestin for drug delivery by local means into periodontal pocket.

A nanostructured 8.5% doxycycline gel was observed to afford periodontal surface preservation following experimental periodontal disease in rats.

BONE GRAFTING The most popular ones to date are nanoHAP (n-HAP) bone

grafts, which are available in crystalline and titanium-reinforced forms. These n-HAP composite bone graft scaffolds are highly biocompatible, have superior mechanical properties, and induce better cellular responses

A clinical study comparing the use of nanocrystalline HAP (NHAP) paste vs open flap debridement (control) in intrabony defects demonstrated clinically significant outcomes in the NHAP group, with a clinical attachment level gain of 3.6 ± 1.6 mm vs the control group’s gain of 1.8 ± 1.2 mm.44 This indicated that the use of an NHAP paste significantly improved the clinical outcome when compared to open flap debridement.

conventional CaSO4 bone grafts have now developed, with particulate sizes ranging from 200-900 nm, while the conventional CaSO4 bone graft particle size ranges from 30-40 µm.

These nanoparticles are further condensed into pellets of 425-1000 µm. This nanotization of particles results in a graft material which is more resistant to degradation and lasts longer (12-14 weeks) than conventional CaSO4 (4-6 weeks). This rate of degradation matches the rate of bone growth in the intrabony defects, resulting in better treatment outcomes

Carbon nanotubes provide a strong, flexible, and inert scaffold on which cells could proliferate and deposit new bone, while the ZnO nanoparticles provide the antibacterial properties. This material enhances HAP formation in bone defects.

The use of nanoparticulate bone grafts show promise in postextraction ridge preservation, intrabony defects regeneration, root perforations, and fenestration corrections.

Nanoparticles can also be designed— using ultrasonic assessment of the bone quality and structure—to simulate bone.

Guided tissue regeneration

The concept of guided tissue regeneration (GTR) is being researched to replace earlier functional graded membranes with novel 3-layered membranes.

The former system included bilayered GTR membranes with a porous surface on one side (for cellular ingrowth), and a smooth surface on the opposite side (for cellular occlusion).

A novel system has come up with a 3-layered GTR membrane composed of an inner- most layer made of 8% nanocarbonatedhydroxyapatite/collagen/polylactic-co- glycolic acid (nCHAC/PLGA) porous membrane, a middle layer of 4% nCHAC/ PLGA, and an outer layer of PLGA non- porous membrane.

These 3 layers combine to form a highly flexible, biocompatible, osteoconductive, and biodegradable composite membrane.

When osteoblastic cells were cultured on this membrane, they showed a more positive response compared to a pure PLGA membrane.

Implants Nanotechnologies are increasingly used for

surface modifications of dental implants as surfaces properties such as chemistry and roughness play a determinant role in achieving and maintaining their long-term stability in bone tissue. Direct bone-to-implant contact is desired for a biomechanical anchoring of implants to bone rather than fibrous tissue encapsulation

Nanomaterials for Healing of Wounds

Nucryst (Wakefield, USA) has made a wound-healing material (dressing) that is generally used in specialist burn-treatment hospitals in America. The dressing contains nanocrystalline silver that stops 150 types of fungus and bacteria, including several bacteria that are resistant to antibiotics. Meanwhile, another company has placed nanoparticles into a plastic material to make it biocidal. This can be useful for devices that are placed inside the body.

CONCLUSION Nanotechnology is part of a predicted future in

which dentistry and periodontal practice may become more high-tech and more effective looking to manage individual dental health on a microscopic level by enabling us to battle decay where it begins with bacteria.

Construction of a comprehensive research facility is crucial to meet the rigorous requirements for the development of nanotechnologies.

Trends in oral health and disease also may change the focus on specific diagnostic and treatment modalities. Increasingly preventive approaches will reduce the need for cure prevention a viable approach for the most of them.

Diagnosis and treatment will be customized to match the preferences and genetics of each patient. Treatment options will become more numerous and exciting. All this will demand, even more so than today, the best technical abilities, professional skills those are the hallmark of the contemporary dentist and periodontist. Developments are expected to accelerate significantly.

REFERENCES SUHAIL Et al Role of Nanotechnology in Dentistry

Scholars Journal of Applied Medical Sciences 2014; 2(2D):785-789

Mayuresh Et al. Nanotechnology: A Boon to Dentistry JDSOR 2014;5(2):78-88.

Shaeesta Et al. Current applications of nanotechnology in dentistry: a review General dentistry; 2014

LING et al. Nanotechnology and its role in the management of periodontal diseases Periodontology 2000,2006; 40: 184–196