nanotechnology in dentistry

NANOTECHNOLOGY IN PROSTHODONTICS

By Dr. Divya SinghMDS

Prosthodontics and maxillofacial prosthesis

INTRODUCTION• “Nano" is derived from the Greek word for 'dwarf' which

combines with a noun to form words such as nanometer, nanotechnology, and nano robot.

• Nanotechnology is the science of manipulating matter on molecular and atomic levels or of matter measured in the billionths of meters or nanometer, roughly the size of 2 or 3 atoms

• Nano technology consists mainly of the processing, separating, consolidating, and deforming of materials by one atom or molecule. Since its origin, the definition of nanotechnology has generally been extended to include features as large as 100 nm.

• The term ‘‘nanotechnology’ ’was coined by a student at the Tokyo Science University in1974(Taniguchi, 1974).

• A nanometer is 10-9 or one billionth of a meter.

• In the literature, both a fairly broad as well as a rather narrow concept of nanotechnology are employed.

• The first signifies any technology smaller than microtechnology.

• In contrast, the latter stands for the technology to program and manipulate matter with molecular precision and to scale it to 3-D products of arbitrary size.

• The basic idea of nanotechnology, used in the narrow sense of the world, is to employ individual atoms and molecules to construct functional structures.

HISTORY OF NANOTECHNOLOGY

• There is much controversy regarding the history of nanotechnology. Although some researchers believe that it is a scientific evolutionary form that did not develop until the late 1980s, evidence of nanotechnology dates back to 1959.Others believe that humans have unwittingly employed nanotechnological methods for thousands of years, perhaps even longer.

• During the 17th century, the idea was developed that utopian ideals, such as control of the natural environment, a perfect society, life without disease and pain, prolongation of life as well as enhancement of man and his characteristics could be achieved through the further development of science. All that was needed for that would be to organize science in a correct way and to work with effective methods. This modern idea became a source of great enthusiasm for nanotechnology development.

Gordijn B.Sci Eng Ethics. 2005 Oct; 11(4):521-33. Nanoethics From Utopian Dreams and Apocalyptic Nightmares towards a more Balanced View

Terminology and basic idea• Richard Feynman ,at an American Physical Society meeting in

1959, gave a lecture, ‘‘There’s Plenty of Room at the Bottom’’ and speculated on radical forms of miniaturization

• Both practically and theoretically, significant progress in the field of nanotechnology started only in the eighties

• 1980s: Gerd Binnig and Heinrich Rohrer, working at the IBM research laboratory in Zurich, developed scanning tunneling microscopy. This new technique can provide an image of the atomic arrangement of a metal or a semiconductor surface. Thus, using this new technique Binnig and Rohrer could, for the first time ever, “map” the arrangement of individual atoms of metals and semiconductors. In 1986 Binnig and Rohrer received the Nobel Prize for their achievements.

• The atomic force microscope represents a further development in microscopy. It enables images of materials inaccessible to the scanning tunneling microscope, for instance insulators, organic materials, biological macromolecules, polymers, ceramics and glasses.

• Foster et al. 1988; Hansma et al. 1988 discovered that scanning tunneling microscopes could also be used to manipulate nanoscale objects

Theoretical development Majorly done by Eric Drexler (1981 & 1986). • pre-programmed maneuvering and goal directed management of

individual molecules.

• In addition, he elaborated on the future development of technical means and methods to arrange matter at the nanoscale.

• Finally, Drexler also discussed the various fields of application for future nanomachines (Drexler, 1981 & 1986). Drexler came up with the idea of the assembler, a molecular machine that can be programmed to build virtually any molecular structure or device from simpler chemical building blocks” .

• This nanoscale construction device can position molecules in every which way, thereby facilitating, for example, chemical reactions.

• According to Drexler, the development of universally applicable assemblers is essential for the further development of nanotechnology. Assemblers could also be programmed to replicate themselves.

State of the field at present• Current research is directed towards the production of a wide

array of different nanoscale structures. The fabrication techniques of these structures can be divided into two approaches: “top-down” and “bottom-up” (Bachmann, 1998; Freitas, 1999; Pool, 1990; Roukes, 2001; Whitesides & Love, 2001).

• The top-down techniques that are used to manufacture nanoscale structures are mostly extensions of methods already employed in small-scale assembly at the micron scale, for example, photolithography. By further miniaturization, the nanodimension is entered (Ashley, 2001). In this way, further miniaturization of microelectronics could result in nanoelectronics (Lieber, 2001).

• Bottom-up fabrication methods for manufacture are studied within synthetic chemistry, which is, almost by definition, the science of producing nanoscale structures. They are also inspired by phenomena such as crystal growth and self-assembly. In a certain way, many bottom-up methods try to imitate regularly occurring processes in nature. Living nature, for example, constantly shapes complex macroscopic structures from individual biomolecular elements.

3 steps to achieving nanotechnology-produced goods 1. Scientists must be able to manipulate individual atoms. 2. Next step is to develop nanoscopic machines, called assemblers, that can be programmed to manipulate atoms and molecules at will. 3.In order to create enough assemblers to build consumer goods, some nano machines called replicators, will be programmed to build more assemblers. • Assemblers and replicators will work together

like hands, to automatically construct products. • Nanotechnology is about manipulating matter,

atom by atom. Just as robots assemble cars from a set of predefined parts, nano-robots work in a similar manner

• Current research is directed towards the production of a wide array of different nano scale structures.

• The growing interest in this field is giving emergence to new field called Nanomedicine, a science & technology of diagnosing, treating & preventing diseases, and preserving & improving human health, using nanoscale structured materials.

• Because of the growing interest in the future of dental applications of nano technology, a new field called nano dentistry is emerging.

• This seminar provides an early glimpse of nano dentistry applications to explain their potentially far reaching impacts on clinical dental practice.

• This seminar also reviews the current status and the potential clinical applications of nanotechnology in nano dentistry.

NANODENTISTRY

LOCAL ANAESTHESIA

TOOTH REPAIR

COSMETICS

NANOMATERIALS

NANO ROBOTS

NANODENTISTRY OVERVIEW

• The future holds in store an era of dentistry in which every procedure will be performed using equipments and devices based on nanotechnology.

• Researchers have predicted that high-tech and effective management at the microscopic level, termed nanotechnology, will become an important part of future dental and periodontal health.

• Nano dentistry can be divided into 2 approaches: “top- down” and “bottom-up”.

• The 'top-down' techniques that are used to manufacture nanoscale structures are mostly extensions of methods already employed in small-scale assembly at the micron scale. By further miniaturization, the nanodimension is entered.

• 'Bottom-up' fabrication methods for manufacture are the methods used for producing nanoscale structures. Methods used for producing nanoscale structure, through this method nanoparticles are produced directly. Various nanoparticles produced through bottom up method and used in dentistry are nanopores, nanotubes, quantum dots, nanoshells, dendrimers liposomes, nanorods, fullerenes, nanospheres, nanowires, nanobelts, nanorings, nanocapsules.

Rybachunk AV, Chelkman IS. Nanotechnology and nanoparticles in dentistry. Pharmacol Pharm 2009;1:18-21.

Nanodentistry as bottom-up approach

• Inducing anesthesia• Major Tooth Repair• Hypersensitivity Cure• Dental Durability and Cosmetics• Nanorobotic Dentifrice (dentifrobots)• Tooth repositioning• Local drug delivery • Nanodiagnostics • Therapeutic aid in oral diseases.

Nanodentistry as top down approach

• Nanocomposites• Nano Light-Curing Glass Ionomer

Restorative Materials• Nano Impression Materials• Nano-Composite Denture Teeth• Nanosolutions • Nanoencapsulation • Plasma Laser application • Prosthetic Implants• Nanoneedles • Bone replacement materials

Nanodentistry as bottom-up approach1. Local anaesthesiaWell-known alternatives, such as transcutaneous electronic nerve stimulation (TENS), cell demodulated electronic targeted anesthesia and other transmucosal, intraosseous or topical techniques, have proved to be of limited clinical efficacy

A colloidal suspension containing millions of active analgesic micron-size dental robots will be instilled on the patient's gingiva. After contacting the surface of crown or mucosa, the ambulating nano robots reach the pulp via the gingival sulcus, lamina propria, and dentinal tubules.

On reaching the dentin, the nanorobots enter dentinal tubule holes that are 1 to 2 micrometer in diameter and proceed towards the pulp, guided by a combination of chemical gradients, temperature differentials and even positional navigation; all under the control of the on-board nanocomputer as directed by the dentist.Assuming a total path length of about 10 mm from the tooth surface to the pulp and a modest travel speed of 100 micrometers per second, nanorobots can complete the journey into the pulp chamber in approximately 100 seconds.

Freitas,R.A.,2000.Nanodent.J.Am.Dent.Assoc.131(3),1559–1566.

• Once installed in the pulp, the analgesic dental robots may be commanded by the dentist to shut down all sensitivity in any particular tooth that requires treatment.

• The presence of natural cells that are constantly in motion around and inside the teeth suggests that such journeys should be feasible by cell sized nanorobots of similar mobility.

• After oral procedures are completed, the dentist orders the nanorobots to restore all sensation, to relinquish control of nerve traffic, and to egress from the tooth by similar simultaneously in real time pathways used for ingress.

Advantages

• Patient has anxiety-free and needleless comfort.

• The anesthesia is fast acting and reversible, with no side effects or complications associated with its use

Nanorobot• A nanorobot is a specialized nanomachine.• It has dimensions in the order of nanometers.• Typically 0.5 to 3 microns large with 1-100 nm

parts made of chemically inert forms of carbon.• The possibility of nanorobots was first

proposed by Richard Feyman in his talk “There’s Plenty of Room at the Bottom” in 1959

• Functions in dentistry• Induces local anaesthesia.• Avoids discomfort to the patient. • Dentrifices (dentofrobots)• Major Tooth Repair

• .

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.

Shellart W.C., Oesterle L.J. uprighting molars without extrusion. JADA

1999;130: 381-5.

• Chen et al in 2003, took advantage of these latest developments in the area of nanotechnology to simulate the natural biomineralization process to create the hardest tissue in the human body, dental enamel, by using highly organized microarchitectural units of nanorod-like calcium HA crystals arranged roughly parallel to each other.

Chen Y, Jung G-Y, Ohlberg DAA, et al. Nanoscale molecular-

switch crossbar circuits. Nanotechnology. 2003;14:462.

• REGENERATIVE NANOTECHNOLOGY • Also know as Dentition renaturalization• This procedure may become popular and provide

perfect treatment methods for esthetic dentistry. • This trend may begin with patients who desire to

have their old dental amalgams excavated and their teeth remanufactured with native biological materials, and full coronal renaturalization procedures in which all fillings, crowns, and other 20th century modifications to the visible dentition are removed, with the affected teeth remanufactured to become indistinguishable from original teeth.

• This technique may revolutionarize cosmetic dentistry.

Freitas RA Jr. Nanodentistry. Journal of American Dental Association. 2000;131(11):1559-65

HypersensitivityIt is characterised by short, sharp pain arising from exposed dentin in response to stimuli typically thermal, evaporative, tactile, osmotic or chemical and which cannot be ascribed to any other form of dental defect or

pathology

• Hypersensitivity cure

• The most common clinical cause of dentin hypersensitivity is exposed dentinal tubules as a result of gingival recession and subsequent loss of cementum on root surfaces.

• Conventional treatment includes1. Desensitisation by occluding dentinal tubules

Calcium hydroxide pasteCalcium phosphate pasteSilver nitrateFluoridesFluoride iontophresisPotassium nitrateVarnishesDentin adhesives

C)placement of restorations Glass ionomer cementsComposite resinsd)use of lasers co2 laser

Nd:yag,er:yag LASER He:ne LASER2. Desensitizing by blocking pulpal sensory nervesA)potassium nitrate toothpaste

• Nanotechnology in conventional methods for treating hypersensitivity

• The Polyhedral Oligomeric Silsesquioaxane (POSS) molecule can be used to reduce tooth sensitivity through sealing the tubules with POSS nano-sized molecules, and provide structural reinforcement, toughness, and processability.

Using Nanorobots• Dentin hypersensitivity may be caused by changes in

pressure transmitted hydro dynamically to the pulp. This is based on the fact that hypersensitive teeth have eight times higher surface density of dentinal tubules and tubules with diameters twice as large as non sensitive teeth.

• Dental nanorobots could selectively and precisely occlude selected tubules in minutes, using native logical materials, offering patients a quick and permanent cure.

Dental durability and cosmetics.• Tooth durability and appearance may be

improved by replacing upper enamel layers with covalently bonded artificial materials such as pure sapphire and diamond which has 20-100 times more hardness and strength than natural enamel and contemporary ceramic veneers and has good biocompatibility. These materials are brittle and can be made more fracture resistant as a part of nanostructured composites, possibly including embedded, carbon nanotubes

Nanotechnology toothpaste

• The small nano partices of Hydroxyapatite helps to prevent the tooth from decaying, it also rebuilds teeth by placing a coating on the tooth to protect it from future damage.

• Active ingredients are Patented nano technology aka Nanoxyd® which is calcium peroxide in nano size, which penetrates into the most minute of gaps, ensuring an optimum bleaching result.

• Enzymes (papain and bromelain) gently remove the plaque

• Co-enzyme Q10 protects against inflammation of the gums.

• Vitamin E protects the teeth and vitalises the gums.

• Fluoride combination protects against tooth decay.

• It whitens and polishes the teeth and makes it less sensitive

• It arranges itself in a way that mimics and binds to the natural enamel structure.

• If Hydroxyapatite is swallowed it does not upset the stomach and is not as toxic as regular toothpaste.

http://blogs.dickinson.edu/mindmeetsmatter/category/nanotechnology-toothpaste/

Nanorobotic dentifrice [dentifrobots]

• Sub occlusal dwelling nanorobotic dentrifice delivered by mouthwash or toothpaste could patrol all supragingival and subgingival surfaces at least once a day, metabolising trapped organic matter into harmless and odorless vapors and performing continuous calculus debridement.

• These invisibly small dentifrobots [1-10 micron], crawling at 1-10 microns/sec, would be inexpensive, purely manufactured non agglomerated discrete nanoparticles mechanical devices, that would safely deactivate themselves if swallowed and would be programmed with strict occlusal avoidance protocol.

• Dentifrobots also would provide a continuous barrier to halitosis since bacterial putrefaction is the central metabolic process involved in oral malodor. With this kind of daily dental care available from an early age, conventional tooth decay and gingival disease will disappear.

Nanodentistry as top down approach

• Nanocomposites• Nano Light-Curing Glass Ionomer

Restorative materials• Nano Impression Materials• Nano-Composite Denture Teeth• Nanosolutions • Nanoencapsulation • Plasma Laser application • Prosthetic Implants• Nanoneedles • Bone replacement materials

Evolution in composites

The chronological development of the state of the art of dental composite formulations based on filler particle modifications.

Nanocomposites

• Nanocomposites• Nanotechnology has had its greatest impact on

restorative dentistry by offering refinements to already clinically proven resin based composite systems.

• Nanohybrid and nanofilled RBCs are generally the two types of composite restorative materials characterized by filler-particle sizes of ≤100 nm referred to under the term “nanocomposite”.

• Nanomers and nanoclusters are the two types of monodispersed non agglomerated discrete nanoparticles that are homogeneously distributed in resins or coatings to produce nano composites.

An application of nanotechnology in advanced dental materials Sumita b. Mitra, Dong WU, and Brain N. Holmes JADA October 2003 134(10): 1382-1390

Materials used to reinforce composites

• Nanomaterials available as titanium dioxide, aluminum oxide and silica oxide are used in small amounts (1%–5%) to improve powder flow of composites. Eg. Isopast® and Heliomolar® by Ivoclar Vivadent

• Nanocream- Nano Aluminium Oxide FibresNano-structural aluminium oxide fibers provide added strength and improved performance to metals, plastics, polymers and composite materials.

• Nanoporous Silica-Filled Composite Nanoporous silica filled composite is a fairly new material still in experimental form, proven to increase wear resistance in posterior applications. Nano sized porous silica fillers allow the monomer to inter- penetrate it, through a capillary force; the monomer is drawn in and out of the filler, reinforcing the composite and increasing the durability of the bonding between the two phases. By impregnating organic monomer into the pores & adding a light cure system a solid organic/inorganic nanostructure is formed.

Silane bonding agents• Together with the evolution of nanoparticles for dental

composites, sharper focus is being applied to reformulations of interfacial silanes

• Organosilanes such as allyltriethoxysilane have demonstrated good compatibility with nanoparticle fillers such as TiO2.

• In addition,3ethacryloxypropyltrimethoxysilane has also been demonstrated to enhance dispersion of silica nanoparticles (5–25 nm) within the restorative resin matrix.

• Silanization has been reported is one of several theoretical avenues for increasing fracture toughness of nanocomposites.

• silanization increased the strength of a novel ion-releasing calcium phosphate (CaPO4) composite, but decreased the level of release.

Current practicality of nanotechnology in dentistry. Part 1:Focus on nanocomposite restoratives and biomimeticsClinical, Cosmetic and Investigational Dentistry 2009:1 47–61

Figure 6: Sem micrograph of filtek supreme [a=x1,000 b=x2,500 magnification] spherical nanocluster of 1 to 4 um

Trade name - filtek O supreme universal restorative pure nano

SEM IMAGE

An application of nanotechnology in advanced dental materials Sumita b. Mitra, Dong WU, and Brain N. Holmes JADA October 2003 134(10): 1382-1390

Advantages • Mechanical strength and wear resistance comparable to hybrid

composites• Superior flexural strength, modulus of elasticity, and translucency• Superior polish and gloss resistance comparable to microfill

composites.• 50% reduction in filling shrinkage• Excellent handling properties• Trade names: • Filtek O Supreme Universal Restorative Pure Nano ,• Premise, Kerr/Sybron, Orange, CA• Trade name of nanohybrids: Nanohybrid NANOSIT™

nanohybrid composite (Nordiska Dental, Angelholm, Sweden• Trade name of nanofills: Filtek™ Supreme Plus [3M ESPE],

Estelite® Sigma [Tokuyama America, Inc., Encinitas, CA, USA])

Ormocers

• Ormocer® is an acronym for organically modified ceramics.

• Ormocers represent a new technology based on sol-gel synthesis using particles comprising silicones, organic polymers, and ceramic glasses that is applicable to dental composites.

• Ormocer® composite technology is used in conjunction with nanoparticle fillers such as ZrO2 that are widely used in nanocomposite restorative systems.

• Some ormocers (such as CeramX™ [Dentsply International]) contain particles as small as 2–3 nm in diameter. Admira (Voco GmBh)

ADVANTAGES

• Modifying ormocers with organic moieties such as methacrylate-substituted ZrO2 or SiO2 organosol nanoparticles was found to improve the mechanical properties of RBCs.

• Ormocers also have decreased surface roughness and superior strength as compared to the other composite systems.

Other features of nano composites..

• Caries prevention• Optimal delivery of molecules that facilitate tooth structure

remineralization and forestall caries.• Fluoride (F)-releasing nanocomposite contains novel

CaF2 nanoparticles in a whisker-reinforced resin matrix, and had sustained F-release values exceeding those of conventional and resin-modified glass ionomers.

• Dicalcium phosphate anhydrous (DCPA) incorporated with nanosilica-fused whiskers found that it increased the strength of the RBC by as much as threefold while releasing CaPO4.

• Zirconia-amorphous calcium phosphate RBC filler, showed good release properties in addition to an increase in biaxial flexural strength

• Nano Light-curing glass ionomer restorative materials

• Blends Nanotechnology originally developed for Filtek™ Supreme Universal Restorative with fluoraluminosilicate (FAS) technology.

Advantages:1. Superb polish.2. Excellent esthetics.3. Improved wear resistanceClinical Indications:- Primary teeth restorations.- Transitional restorations.- Small Class I restorations.- Sandwich restorations.- Class III and V restorations.- Core build-ups.

Impression Materials• Nanofillers are integrated in vinylpolysiloxanes,

producing a unique addition of siloxane impression materials.

• The material has better flow, improved hydrophilic properties hence fewer voids at margin and better model pouring, and enhanced detail precision.

Advantages:1. Increased fluidity2. High tear resistance,3. Hydrophilic properties4. Resistance to distortion and heat resistance

5. Snap set that consequently reduces errors caused by micro movements

• Trade name: Nanotech Elite H-D

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.

Advantages:• Excellent polishing ability and stain-resistant• Superb esthetics, lively surface structure• Enhanced wear resistance and surface hardness• Trade name: Veracia( Shofu, Kyoto, Japan) The three

layered Veracia SA teeth consist of MF-H (microfilled hybrid) composite, reinforced with layered glass.

Nanosolution Nanoadhesives• The new bonding agents manufactured from nano

solutions contain stable nano particles homogeneously dispersed throughout the solution.

• The silica nano filler technology contributes to higher bond strength performance. Since the nano particles are stable, they do not cluster nor do they settle out of dispersion. Nano Interaction Zone" (NIZ - <300 nm) with minimal decalcification and almost no exposure to collagen fibres producing an insoluble calcium compound for a better bond less likely to deteriorate from enzymes contained in the mouth.

• 10% 5 nm spherical silica is used as the filler.• Trade name: Adper O Single Bond Plus Adhesive Single u

NanOss™ (Angstrom Medica, USA) HA Bond

Nanoadhesive – Poss

• Polyhedral Oligomeric Silse Squiox (Poss) enables the design of additives that make plastics that are unusually lightweight, durable, heat-tolerant and environment friendly.

• Poss combines organic & inorganic materials in molecules with an average diameter of 1.5 nanometers. They can be used as either additives or replacements for traditional plastics.

• Current applications of Poss include dental adhesives in which a strength resin provides a strong interface between the teeth and the restorative material.

• In addition, tests have shown that Poss materials are much more resistant to radiation damage and erosion than conventional polymers.

Rybachuk AV, Cekman IS. Nanotechnology And Nanoparticles In Dentistry. Pharmocol Pharm 2009;1:18-21

Advantages:• Broad spectrum• Hypoallergic• Non corroding• Does not stain fabric• Require no protective clothing• Environment friendly• Compatible with various impression

materials.

Coating agents

• These light cured agents contain nanosized fillers and are used as a final coating over composite restorations, glass ionomer restorations, jacket crowns, veneers and provisionals. These coating agents have higher wear resistance, preventing abrasion and discolouration.

• Recently, a nanotechnology liquid polish system was designed to overcome the limitations of liquid polishers. The addition of nanofillers provides excellent results such as a glossy surface for direct or indirect resin composite restorations.

Atabek D, Sillelioglu H, Olmez A. The efficiency of a new polishing material: Nanotechnology Liquid Polish. Oper Dent 2010;35:362-69. Back to cited text no. 14

NANOTECHNOLOGY IN IMPLANTS

• Researchers have experimented with implants made of metals that look more natural than titanium. There has been some success with the metal zirconia and a rare metal called tantulum, was discovered. These metals are still not widely used.

• Oral surgeons have discovered that implants that are porous actually help with healing. So many implants now come with tiny holes or rough surfaces.

• Many dentists also use implants improved with nanotechnology to create coatings that promote healing. The biologically active coating creates a more stable bond, according to several large studies.

• Application of nanotechnology to the dental implant surface involves a two dimensional association of surface features (across and away from the mean surface plane)

• These nanofeatures can be arranged in an organized manner (isotropic) or unorganized manner (anisotropic), usually it is anisotropic.

• When these concepts are applied to the endosseous implant surface, implied is the embellishment of the surface with nanometer-scale features that lead to novel physicochemical behavior (e.g. bone bonding) or biochemical events (e.g. altered protein adsorption, cell adhesion with changes in cell behavior).

Advancing dental implant surface technology – From micron to nanotopographyG. Mendonça et al. / Biomaterials 29 (2008) 3822–3835

• First approach involves the physical method of compaction of nanoparticles of TiO2.

• Second is the process of molecular self-assembly. The exposed functional end group could be an osteoinductive or cell adhesive molecule. An example of this is the use of cell adhesive peptide domains composed of polyethylene glycol (PEG) and applied to the titanium implant surfaces

• A third method is the chemical treatment of different surfaces to expose reactive groups on the material surface and create nanoscale topography.

• NaOH treatment catalyzes the production of titanium nanostructures outward from the titanium surface . Treatment with a NaOH solution produces a sodium titanate gel layer on the Ti surface while H2O2 produces a titania gel layer.


• The NaOH treatment creates a gel-like layer over the material allowing hydroxyapatite deposition. This behavior has also been seen with other metals such as zirconium and aluminum .

• The kinetics of HA formation is significantly accelerated by the presence of the nanostructure associated to the NaOH treatment. Both chemical and topography changes are imparted.

• Chemical treatments (peroxidation (H2O2) or acid oxidation, such as hydrofluoric acid) , treatment with HCl have also been used to create nanotopography an helps to increase the peptide deposition and remineralization.


• The deposition of nanoparticles onto the titanium surface represents a fourth approach to imparting nanofeatures to a titanium dental implant . Sol–gel transformation techniques achieve deposition of nanometer-scale calcium phosphate accretions to the implant surface .

• Alumina, titania, zirconia and other materials can also be applied. The deposition of discrete 20–40 nm nanoparticles on an acid-etched titanium surface led to increased mechanical interlocking with bone and the early healing of bone at the endosseous implant surface in a rat model.

• A fifth approach to creating nanoscale topography on Titanium is the use of optical methods (typically lithography) reliant on wavelength specific dimensions to achieve the appropriate nanoscale modification.


Nanotreatments done on the surface of implants

• The determining factors for successful osseointegration are surface contact area and surface topography . Bone growth and increased predictability can be effectively expedited with implant by using nanotechnology.

• The addition of nanoscale deposits of hydroxyapatite and calcium phosphate creates a more complex implant surface for osteoblast formation (Albrektsson etal.,2008;Goeneetal.,2007).

• These new implants are more acceptable, because they enhance the integration of Nano coatings resembling biological materials to the tissuesOTHER FEATURES

• Antibiotics or growth factors may be incorporated as CaP coating is placed on Ti implants. eg: Nanotite™ Nano-Coated Implant.

• Radiopacity• Nanoparticles may be incorporated in materials and

instruments to achieve radiopacity without affecting properties or the risk of toxicity and carcinogenicity associated with heavy metals.

• Bone replacement materials• Bone is a natural nano composite made up of organic

compounds (mainly collagen) toughened with inorganic compounds like hydroxyapatite. This architecture should be simulated for orthopedic and dental use. Also, with the reduction in particle size, the surface area increases manifold. This rule has been utilized by Nano-Bone®.

• Characteristics of nano bone graft materials are:• Osteo inductive• Completely synthetic• Non-sintered• Extremely porous• Nano-structured• Degradation by osteoclasts• Excellent processability• No products in ionic solution• Bone targeting nanocarriers • Calcium phosphate-based biomaterial has been developed. This

bone biomaterial is an easily flowable, moldable paste that conforms to and interdigitates with host bone. It supports growth of cartilage and bone cells.

• Various HA nanoparticles used in repairing osseous defects are;

• • Ostim ® HA.• • VITOSS ® HA+ TCP.• • NanOss HA

Conventional calcium sulphate has been used to plug small osseous defects like in post extraction sockets and periodontal bone defects and in addition to bone graft material. A new calcium sulphate based composite has been developed by, known as Bone Gen –TR which breaks down more slowly and regenerates bone more effectively.

Challenges faced by nanodentistry • Precise positioning and assembly of molecular

scale part.• Economical nanorobot mass production technique • Biocompatibility• Simultaneous coordination of activities of large

numbers of independent micron-scale robots. • Social issues of public acceptance, ethics,

regulationProblems for research in nanotechnology • Painfully slow strategic decisions • Sub-optimal funding • Lack of engagement of private industries• Problem of retention of trained manpower

CONCLUSION

A day may soon come when nanodentistry will succeed in maintaining near-perfect oral health through the aid of nanorobotics, nanomaterials and biotechnology. “You have to be able to fabricate things, you have to be able to analyze things, you have to be able to handle things smaller than ever imagined in ways not done before.” - William Philips Richard .P Feynman

The Next Big Thing Is Very Small…

THANK YOU

References

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• Nanotechnology in dentistry: Present and future Journal of International Oral Health 2014; 6(1):121-126

• Nanorobots: Future in dentistry The Saudi Dental Journal(2013) 25, 49–52

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• Future impact of nanotechnology on medicine and dentistry Journal of Indian Society of Periodontology - Vol 12, Issue 2, May-Aug 2008

• Current practicality of nanotechnology in dentistry. Part 1: Focus on nanocomposite restoratives and biomimetics Clinical, Cosmetic and Investigational Dentistry 2009:1 47–61

• The changing face of dentistry: nanotechnology International Journal of Nanomedicine 2011:6 2799–2804

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• Cover Story Robert A. Freitas Jr., J.D., B.S JADA, Vol. 131, November 2000

nanotechnology in dentistry

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