One step to forward biomaterials - copy

One step to forward- BiomaterialsDr. Kyaw TintAssociate ProfessorDepartment of ProsthodonticsUniversity of Dental Medicine, Yangon

Today presentation includesIntroduction.Bone SubstituteMembrane- Resorbable &Non-resorbableTitanium- Fixture, MeshZarconiumNanotechnology- General, Clinical

BiomaterialDefinition -material exploited in contact with living tissues, organisms,or microorganisms

- can be derived either from nature or - synthesized in the laboratory - using a variety of chemical approaches - utilizing metallic components, polymers, ceramics or composite materials

Ideally, a biomaterial

should be non-toxic, non-irritant, have no carcinogenic or allergic potential and, if used as a filling material, should be harmless to the pulp

ScopeThe field of biomaterials science encompasses all classes of material, i.e. polymers, ceramics, glasses and metals, and a wide range of branches of surgery: dental, ophthalmic, orthopaedic, cardiovascular and so on.

Biomaterials are used in: Joint replacements Bone plates Bone cement Artificial ligaments and tendons Dental implants for tooth fixation Blood vessel prostheses Heart valves Skin repair devices (artificial tissue) Cochlear replacements

Contact lenses Breast implants Drug delivery mechanisms Sustainable materials Vascular grafts Stents Nerve conduits Surgical sutures, clips, and staples for wound closure

BiocompatibilityBiocompatibility is related to the behavior of biomaterials in various environments under various chemical and physical conditions. For example, a material may elicit little or no immune response in a given organism, and may or may not able to integrate with a particular cell or tissue.

Biocompatibility

not a property of a material per se; the material needs to elicit an appropriate response,distinct from that of inertness, which would imply a complete absence of response from the body (e.g GP points)

BiopolymersProduced by living organisms.e.g- Cellulose and starch, proteins and peptides, and DNA and RNA in which the monomeric units, respectively, are sugars, amino acids, and nucleotides.

Biomaterial as scaffoldWhen the damage is so extreme that it is impossible to use the patients own cells, artificial tissue cells are grown. The difficulty is in finding a scaffold that the cells can grow and organize on.The characteristics of the scaffold must be that it is biocompatible, cells can adhere to the scaffold, mechanically strong and biodegradable.

Bone Substitutes

collagen is the building block of the organic matrixa triple helix with diameter of 1.5 nm.

the hydroxyapatite crystals are platelets that have a diameter of approximately 70 100 nm and thickness of 1 nm. They originally nucleate

at the gaps between collagen fibrils.Bone constituents

What are..Osseoinduction is the ability to promote de novo bone formation remote from the host bone even within noncalcified tissues

Osseoconduction is the property of promoting bone growth from the surrounding host bone onto the surface of the graft material, using the graft as a framework

Autogenous bone grafts Availability Sterility Biocompatibility Osseoinductive potential Osseoconductive potential Ease of use

Autogenous bone graft

The ideal characteristics of asubstitute bone graft materialSterileNon-toxicNon-immunogenicOsteoinductive or osteoconductiveFavorable clinical handlingResorption and replacement by host boneSynthetic Available in sufficient quantities Low in cost

Allograft (Allogenic grafts)Bone derived from cadaversThe graft may be freezedried or decalcified freeze-dried bone allograft (DFDBA),A good source of bone morphogenetic proteinThey are osteoconductive, providing a framework for new bone growthAvailable in varying thicknesses of 20700 m,

XenograftDeproteinized bovine bone mineralSimilar properties to human cancellous boneAs a purely mineral(Calcium) graft it is osseoconductiveMixed with the patients blood and packed into the defectAs a filler to increase the volume of autogenous graft material

Alloplastic graft materialsno risk of cross-infectionbut may still give rise to an antigenic responseas a framework for bone formation on their surface and are therefore osseoconductive They include:

- Hydroxyapatite , Calcium Phosphate - Tricalcium Phosphate (TCP), Bioactive Glasses - Calcium Carbonate

Alloplast: Bioactive Glass NanoparticlesBioactive glasses were first developed by Hench et al. in 1969 in different forms, such as bulk, powder, composites, and porous scaffolds.able to bond to mineralized bone tissue in physiological environment

Composition and synthesis of bioactive glass nanoparticlesThe sol-gel-derived bioactive glasses, the composition of 60% SiO2, 36% CaO, and

4% P2O5 (by weight) has a high level of bioactivity,The synthesis of bioactive glass uses typical precursors like tetraethyl orthosilicate (TEOS), calcium nitrate (CN), and triethylphosphate (TEP).

Bioactive glass in dentistryuse as bone grafts, implant coatings, bone cements, toothpaste, and various other applications in dentistry.e.g-Bioglass, PerioglassBioactive glasses are known for osteoconductivity and bonding to bone through the release of ions and formation of a layer of apatite

New alloplast: Bioactive glass + PolymersThe combination of biodegradable polymers and bioactive ceramic creates a new type of material for tissue engineering applicationsSeveral synthetic or natural polymers, such as polyvinyl alcohol (PVA), chitosan, polyethylene

glycol (PEG), gelatin, collagen, poly(caprolactone) (PCL), and polyurethanes, are used to construct nanocomposites for tissue engineering applications

Membranes

Non-resorbable membranes for Guided bone regenerationexpanded polytetrafluoroethylene (PTFE, Gore-Tex)requires removal at second-stage surgeryThe creation and maintenance of a volumetric

defect is critical and this may be improved by reinforcing PTFE membranes with titanium strips

Non-resorbable membrane

Resorbable membranes for Guided bone regenerationMade of synthetic polymers such as polylactate and polyglycolic acid, as well as collagen membranesResorbable materials should be functional for between 3 and 6 months after insertion

GTR & GBR

Titanium

The alpha () alloys have a hexagonal closely packed (hcp) crystallographic structure, while the beta alloys () have a body-centred cubic (bcc) form Aluminium is an alpha-phase stabilizer and increases the strength of the alloy, while it decreases its density. On the other hand, vanadium is a beta-phase stabilizer

Efforts to promote osteointegration

It is better to know Mesenchymal Stem Cells

Origin of mesenchymal stemm cellsWhile originally identified in the bone marrow MSCs have been extracted from numerous

tissues including adipose , heart, dental pulp , peripheral blood, and cord blood. One of the major properties of MSCs is their ability to differentiate into various cells.like adipocytes , chondrocytes, osteoblasts , neurons, muscles , and hepatocytes in vitro after treatment with induction agents

Migration, adhesion, and proliferationstimulated in vitro by many growth factors including Platelet-derived growth factor (PDGF) , Epidermal growth factor (EGF) , Vascular endothelial growth factor (VEGF) ,

Transforming growth factor (TGF-) , Bone morphogenetic protein-2 (BMP-2) and BMP-4plasma clot serves as storage to fibrin molecules and release system for a variety of

bioactive factors

Migration, adhesion, and proliferationAfter MSCs recruitment in the injured site, cells adhere on the local extracellular matrix as well as on the implant surface beginning an extensive proliferation in order to build up new tissue.

DifferentiationUnder the influence of these growth factors, MSCs switch to osteoblastic cells

In some cases, implants are encapsulated by fibrous tissue due to the proliferation and differentiation of MSCs into fibroblastic cells

Implant failure from chemical point of viewtitanium implants may adsorb hydrogen from the biological environment, consequently becoming more brittle and prone to fracture Green et al. suggested that galvanic corrosion between non-precious metal alloy restorations supported on titanium implants might initiate a cytotoxic reaction

Implant fracture

Titanium mesh

Lateral ridge augmentation with additional cortical perforation, titanium mesh, nano-HA bone substitution, reentry after 6 months, removal of titanium mesh, gained alveolar ridge

Zarconia

ZarconiaCeramics, particularly the yttrium-stabilized tetragonal polycrystalline zirconia (Y-TZP), exhibit improved mechanical properties that make them suitable substrates for the fabrication of dental implants Yttria- a greyish-white metal resembling the rare earth elements (Y)- atomic no. 39

ZarconiaFlexural strength -800 to 1000 MpaFracture strenth- 512 N versus 410.7 NMelting point- > 2370 CAlloying pure zirconia with stabilizing oxides, such as CaO, MgO, Y2O3 or CeO2, allows the retention of the metastable tetragonal structure at room temperature.

Types of Zirconia Used in Dentistry Yttrium-Stabilized Tetragonal Zirconia Polycrystals (3Y-TZP) Glass-Infiltrated Zirconia-Toughened Alumina (ZTA) Alumina Toughened Zirconia (ATZ)

Low Temperature Degradation of ZarconiaAlso known as ageing- occurs by a slow surface transformation of the metastable tetragonal crystals to the stable monoclinic structure in the presence of water or water vapour.

How to prevent ageing of ZarconiaA decrease in grain size and an increase in stabilizer content were found to retard the transformation process. The critical grain size reported in the literature ranges from 0.2 to 1 m depending on the Y2O3 content

Bending load ---> peri-implant bone resorption---> crown to implant ratio ---> bending moment combined with lateral occlusal loading premature implant failure

Failure mode of Zarconia

Failure Mode of Zarconia

Failure mode of ZarconiaSharp, deep and thin threads as well as sharp internal line angles represent areas of stress concentration that can enhance the likelihood of crack propagation and implant failure A reduced implant diameter of 3.25 mm, associated with a higher bending moment, has also been reported by Gahlert et al. to be a contributing factor for implant fracture during functional loading

Failure mode of ZarconiaDuring surgical procedures, difficulties can be encountered when inserting the implants in dense hard-type bone. If hand torqueing is needed for final insertion of the implant and the applied forces are not purely rotational in nature, bending forces may be generated, resulting in implant failure

Osseointegration of Y-TZP versus Titanium Dental Implants the mean bone-implant contact was above 60%, indicating successful osseointegration zirconia implants undergo osseointegration similar to or even better than that of titanium implants titanium implants were found to have a higher removal torque resistance, probably due to the difference in the surface roughness

Modifications to ZarconiaUV treatment of zirconia - significant decrease in carbon content and conversion of the surface from hydrophobic to hydrophilic status

Coating the surface of Y-TZP implants with bioactive glass was also reported to accelerate bone healing and to improve the osseointegration process

Peri-Implant Soft Tissueszirconia implants and abutments provide a very good peri-implant soft tissue interface that achieves an irritation-free attachment

The zirconium oxide surfaces showed a significant reduction in bacterial adhesion when compared to the titanium specimens

Clinical Studies, Case Reports and Case Series on Zirconia Implants survival rate of 74%98% after 1256 monthssuccess rates between 79.6% and 91.6% after 612 months of prosthetic restoration

However, the urgent need for well-conducted, long-term, randomized controlled trials to establish an evidence-based use of zirconia implants

Using rapid prototyping technology, a 3D custom-made layered structure can be constructed through computer-controlled extrusion of colloidal pastes, slurries or inks .

The benefit of this technique over the conventional milling method is that it is more economical with minimal material wastage

Nanotechnology

A: Definition & Histroy

NanotechnologyNano is derived from the Greek word for dwarf.

American Physicist and Nobel Laureate Dr. Richard Phillips Feynman who presented a paper called There is plenty of room at the bottom in December 29, 1959, at the annual meeting of the American Physical Society at California Institute of Technology

History of nanotechnology In 1959 Richrad Feynman presented ideas for creating Nano scale machines Norio Taniguchi introduced the termnanotechnology1980s, development in this field was greatly enhanced with advances in electron microscopy

A nanometer isone billionth of a meter, or 3 to 5 atoms in width. 40,000 nanometers lined up in a row to equal the width of a human hair.

Nanotechnology can be approached in two ways: top-down and bottom-up approaches

Approaches in nanotechnologyTop-down ApproachCreating Nano-scale materials by physically or chemically breaking down larger materialsBottom-up ApproachAssembling Nano materials atom-by-atom or molecule-by molecule (self assembling)

Two ways approaches

Top-downBottom-upMethodminiaturizationagglomerationFrommacroscopicAtoms or moleculesToMicro/nanoscaleMacromolecularTechMachining/etchingSelf-organize/ self-assemblee.gSemi-conductorCochlear replacementspolymer

Dip-pen nanolithography ( DPN)

B:Type of Nanomaterials

Three general categories of nanoparticles

(i) environmental, such as those generated from forest fires and volcanoes,

(ii) nonengineered, by-products of human activity

(iii) engineered, such as those being developed for diagnostic imaging and as vehicles for drug delivery

Engineered nanomaterials five general types:

(i) carbon-based(ii) metal-based metal oxides(iii) semiconductor nanocrystal- quantum dots(iv) dendrimers, three-dimensional polymer (v) silica-based,

Carbon nanotubes (sensors, fuel cells, computers and televisions)

Nano membrane filtration systems (safe, clean, affordable water)

The average size of silver nanoparticles is approximately 50-80 nm.

Molecular electronic cross bar latches (tiny Nano devices)

Quantum dots and artificial atoms (small devices that contain a tiny droplet of free electrons)

Carbon nanotubes dendrimers

Why we use this techAfter decreasing material size into the nanoscale, dramatically increased surface area, surface roughness, and surface-area-to-volume ratios to lead to superior physiochemical properties (i.e., mechanical, electrical, optical, catalytic, and magnetic properties).Resulting --Quantum size effect- electronic properties of solids are altered (attractive Vander Waals forces

Carbon nanotube

Carbon nanotubes (sensors, fuel cells, computers and televisions)

Nano membrane filtration systems (safe, clean, affordable water)

Carbon-nanotubeA number of biological molecules can be incorporate into electrospun fibers- natural fibers such as chitosan, collagen, silk, hyaluronic acid, gelatin, fibrinogen have been electrospun into fibers.

Effect: immobilization of bacteria as carriers for drug and as controlled release agent

Electrospinning in cabon nanotube

Layer-by-layer assemblyimmersing a negatively (or positively) charged substrate in an oppositely charged polyelectrolyte which is adsorbed onto the substrate ( Electrodeposition) After equilibrium is reached, the substrate is removed, rinsed, dried, and immersed in a negatively charged polyelectrolyte solution. This process is repeated until the desired thickness is achieved.

Cabon-nanotubeTwo important criteria interfacial adhesion between the CNT and the polymeric matrix, and a homogeneous dispersion of CNT in the matrix

CNT cytotoxicityMost of the as-produced CNTs contain substantial amounts of impurities such as metal catalyst (Co, Fe, Ni, Mo, and Pt). Some of the metals (Co, Ni, Co21) cause cytotoxic or genotoxic effects as well as lung diseases including fibrosis and asthma

Purification for CNTSeveral techniques have been used to purify the as-processed nanotubes. These include

- acid treatment , - thermal oxidation , - acid treatment with thermal oxidation , - combination of ultrasonication and centrifugation using organic solvents

Carbon nanotube in DentistrySWNT- single walled carbon nanotube (< 189nm)MWNT- multi walled carbon nanotube (220-825nm)

Higher degree of sidewall functionalization leads to reduced cytotoxicity. Functionalized CNTs can cross the cell membrane and accumulate in the cytoplasm without being toxic to cells

Application to

- dental restoration materials, - bony defect replacement therapy, - protein, gene, and drug delivery and cancer treatment.Carbon nanotube in Dentistry

CNT applications in restorative dentistryFunctionalized SWNT has been applied to the dental composite to increase its tensile strength and Youngs modulus to help improve the longevity of composite restoration in oral cavityAlso can reduce the chance of secondary decay development in the long term by providing protection against decay inducing bacteria and initiating HA nucleation on its surface

CNT in bony defect replacement therapyNanoscale HA was formed on the surface of MWNT when immersed in calcium phosphate solution of 37C for 2 weeksA biomembrane by electronspinning a suspension of poly (L-lactic acid) (PLLA), MWNT and HA to promote guided bone regenerationA new chitosanMWNT composite has been developed which can promote osteoblast proliferation and apatite crystal formation on the surface of MWNT while discouraging adhesion of fibroblast

Metal Nanoparticles

As antimicrobial agentsCopper oxide (CuO and Cu2O)Zinc Oxide (ZnO)Titanium dioxide (TiO2)

---Semi-conducting, simplest member, high temperature superconductivity, high electron correlation effect, spin dynamics and cheap

Synthesis of fluorescent metal core-shell nanoparticlesCobalt Ferrite

CuO nanoparticlesgenerated by thermal plasma technology, particle sizes -range 20-95 nm with a mean surface area of 15.7 m2/gIn suspension showed activity against a range of bacterial pathogens, including MRSA , E. coli,

(MRSA)-methicillin-resistant Staphylococcus aureus

Titanium Oxidesparticle size in 18 nm; surface area: 87 m2/g

have a growth inhibitory and killing effect against E. coli and MRSA have been shown to be 1.0-2.5 and >2.5 mg/mL

Treatment of oral cancer using nanoparticulate drug delivery systemA single dendrimer can carry an anticancer drug molecule that recognizes cancer cells, a therapeutic agent to kill those cells.

Silica based nanoparticles

Silica nanoparticlesSilica is an oxide of silicon ( silicon dioxide, SiO2) Silica in the form of orthosilicic acid is the form predominantly absorbed by humans and is found in numerous tissues including bone, tendons, aorta, liver, and kidney

Synthesis of silica-based nanomaterialsPyrogenic- combusting or heating

modification of silica to use in dentistry addition of - methacryl-oxypropyl-trimethoxy-silane (-MPS) to silica-based nanomaterials used to improve adhesion of the nanoparticles within the resin matrix, as well as to reduce agglomeration

Skeletal applications of silica-based nanomaterialsOsteoblasts grown on silica-coated disks demonstrated increased hydroxyapatite formation although alkaline phosphatase and cell number was not changedSilica has also been incorporated into hydroxyapatite/bioceramic artificial bone scaffolds, where it is reported to enhance osteoconductivity and proliferation

Skeletal applications of silica-based nanomaterialssurprisingly, 50 nm silica nanoparticles have been detected to cross the bloodbrain barrier in mice although without apparent negative effects or toxicity

C:Nano-systems in Clinical Dentistry

Nanosystems with dental applications

Nano & Restorative Dentistry

Process of Tooth Decay ( L= Lactate)

Nanobiomaterials in Restorative DentistryDental nanocomposites- silicon dioxideSilver nanoparticles anti-bact:, fungal, viralNanocomposites in bone regeneration

Glass Ionomers, Composite, Adhesive- had already known in Curicullum

Silver Nanoparticles:

1 g of silver has 1.6 x 1022 atomsOne atom 0.165 nm x 7 atoms= 1 nm Silver nanoparticles are known for their broad-spectrum antimicrobial activity against bacteria,

fungi, and viruses

Future prospective in adhesive dentistry1. On-demand antibacterial adhisives2.Improving adhesive polymerization through catalytic activity of nanoparticles3.Antibacterial orthodontic adhesives containing nanosiver4.Radiopaque dental adhesives5. Self-adhesive composites6. Self-healing adhesives7. High-speed AFM (atomic force microscopy)

Nano & Prevention

Main strategies for implementation of nanosized materials indental prophylaxis(i) the interaction with bacterial adherence and oral biofilm formation and (ii) the impact on de- and remineralization

Nanobiomaterals in Preventive Dentistryformation of the acquired pellicle which occurs almost instantaneously on all solid substrates exposed to the oral fluidsIt offers protection against erosive mineral loss and modulates de- and remineralizationLonger exposure to beverages or acids at low pH inevitably leads to destruction of the pellicle and continuous mineral loss

Nanobiomaterals in Preventive Dentistrythe pellicle contains a couple of specific and unspecific antibacterial and antimicrobial proteins, glycoproteins, and peptides (such as secretory immunoglobulin A or lactoferrin) as well as, and enzymes (such as lysozyme or peroxidaseDespite these antibacterial properties, the pioneer bacteria have adapted to the protective properties of the pellicle layer

Nanosized calcium fluorideNano-CaF2 powder containing clusters of 10-15 nm sized crystallite particles has been prepared from Ca(OH)2 and NH4F solutions using a spray drying technique1-min application of this nano-CaF2 rinse produces a significantly greater 1-h postrinse salivary fluoride content (158 mol/L) than a NaF rinse (36 mol/L)

Nanomaterial in enamel and dentine remineralizationnano-HA helped mineral deposition predominantly in the outer layer of the lesioncombined GCE( Galla Chinensis) and nano-HA treatment on promoting the remineralization of initial enamel lesionNanosized casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) prevents demineralization and promotes remineralization of initial enamel lesions

Nanomaterial in dentin-pulp complex regenerationThere is evidence suggesting that odontoblasts (cells that produce dentin), dental pulp stem cells (DPSC) and stem cells from human exfoliated deciduous teeth (SHED) are able to produce pulp/dentin-like tissues when seeded on specific condition or scaffoldsSHED mixed with nanofiber peptide scaffold and injected into full-length root canals were able to generate a dental pulp

Dentin hypersensitivitya glycerine-enriched gelatine gel containing phosphate and fluoride ions is as effective as the clinically established application of a glutaraldehyde containing agent (Gluma) in treatment of patients suffering from dentin hypersensitivity

Nano & Oral Biofilm

What is biofilm?an aggregate of microorganisms in whichUp to 1000 different species of bacteria at 108-109 bacteria per milliliter saliva or per milligram dental plaqueDepend on oxygen levels and anaerobiosis, availability of nutrients, exposure to salivary secretions or gingival crevicular fluid (GCF), masticatory forces, oral hygiene procedures

What is acquired pellicle?Contents-several salivary components such as secretory immunoglobulin A (sIgA) and lysozyme, Function-

-provide both barrier and buffering functions -both de- and remineralization processes of the teeth are also mediated by the pellicle

ACP- Amorphous Calcium PhosphateCPP- Casein phosphopeptides

Biofilms and oral infectionsBiofilms of oral bacteria and yeasts can cause a number of localized diseases in the oral cavity, including dental caries, gingivitis, periodontitis, candidiasis, endodontic infections, orthodontic infections, and peri-implantitis(known pathogenesis)

The nanosized apatite particles adsorbed to the bacterial surface might interfere with the bacterial adhesins, which are important for irreversible binding of bacteria to the tooth surface

Antiadhesive nanoparticles and oral biofilm controlChitosan nano- and microparticles . Silica and silicon nanoparticles Hydroxyapatite and other calcium phosphate-based systems

Chitosan nano- and microparticlesChitosan is a biopolymer derived by the deacetylation of chitin, a natural polymer occurring in the exoskeleton of crustaceans. Chitosan is positively charged and soluble in acidic to neutral solution, enabling it to bind to mucosal surfacesCrustaceans- aquatic arthropods: crabs, lobsters, shrimps etc.(other two mat: had already known)

Nanoparticles and the Control of Oral Biofilms

Photodynamic therapy and the use of nanoparticles to control oral biofilmsThe killing of microorganisms with light depends upon cytotoxic singlet oxygen

and free-radical generation by the excitation of a photoactivatable agent or sensitizer The photosensitizer erythrosine has an advantage over other dyes because it is currently used in dentistry to visualize dental plaque in vivo, and so its lack of toxicity in the host

Nano & Orthodontics

BracketsThe surface characteristics (roughness and surface free energy (SFE)) of the brackets play a significant role in reducing friction and plaque (biofilm) formation.Micro- and nanoscale roughness of these brackets can facilitate early bacterial adhesion.

AFM image of retrieved NiTi archwire exposed in oral cavity for 1 month, depicting rough surface producedby calcification on wire surface

Friction reducing nanocoatings on orthodontic archwiresThe types of wires most commonly used are stainless steel, NiTi, and beta-titanium alloy wires (composed of titanium, molybdenum, zirconium, and tin)Dry lubricants composed by nanoparticles are solid phase materials that are able to reduce friction between two surfaces sliding against each other without the need for a liquid media.

Friction reducing nanocoatings on orthodontic archwiresInorganic fullerene-like nanoparticles of tungsten disulfide (IF-WS2) which are potent dry lubricants reduced up to 54% of frictional force when compared to uncoated stainless steel wire

Friction reducing nanocoatings on orthodontic archwiresNiTi substrates were coated with cobalt and

IF-WS2 nanoparticles film by electrodeposition procedure and the friction test results showed up to 66% reduction of the friction coefficient on the coated substrates when compared to uncoated substrates

Studies on Nanoparticle Applications in Materials Used in Orthodontics

SEM of hydroxyapatite (A) and fluoroapatite (B) nanopowders

Nanoparticle delivery from orthodontic elastomeric ligaturesThe release of anticariogenic fluoride from elastomeric ligatures has been reportedMedicated wax applied to orthodontic brackets that slowly and continuously released benzocaine was shown to be significantly more effective in reducing pain associated with mucosal irritation caused by brackets

Future in orthodonticsThe use of shape-memory polymer in orthodonticsBioMEMS/NEMS for orthodontic tooth movement and maxillary expansionNanorobot delivery for oral anesthesia and improved oral hygeineTemporary anchorage devices

Applications of Micro Electromechanical Systems (MEMS)Nano Electromechanical Systems (NEMS) in Orthodontics

Nano & Prostho:

Denture-induced stomatitis related with fungal infection on palate and vestibule of maxilla

Silver Nanoparticles IncorporatedAcrylic-Based Tissue ConditionerAcrylic-based tissue conditioner

The average size of silver nanoparticles is approximately 50-80 nm.

In vitro antimicrobial effects on S. aureus, Streptococcus mutans, and C. albicans

Nano & Dental Implant

Impact of Nanotechnology on Dental Implants

TiO2 nanotubes on TitaniumTiO2 nanotubes on Ti improved the production of alkaline phosphatase (ALP) activity by osteoblastic cells Since ALP is a marker of osteogenic differentiation, these surfaces may demonstrate enhanced bone tissue-integrative properties

Fabrication of NTs on TiThe NTs are generally fabricated in the aqueous hydrofluoric acid (HF) electrolyte in a two-electrode electrochemical cell at a constant potential between 5 and 35 V

Nano & Perio

Nanotechnology for periodontal regenerationYang et al. developed an electrospun nano-apatite/PCL composite membrane for GTR/GBR application, the results showed that the electrospun membrane incorporating nanoapatite is strong, enhances bioactivity and supports osteoblast-like cell proliferation and differentiation

Nanotechnology for periodontal regenerationAlginate/nano bioactive glass ceramic (nBGC) (synthesis of nBGC particles) composite scaffolds were successfully fabricated using lyophilization technique and characterizedThe composite scaffolds had a pore size of about 100-300 m

Periodontal ligament cells on scaffoldConfocal laser microscope images of PDLCs on PLLA (poly L-lactic acid), PLLA/HA, and PLLA/MWNTs/HA membranes

Surface calcium mapping using EDS(Energy Dispersive Spectroscopy) on substrates with cells 4 weeks after cell plating

Bioactive Glass Nanoparticles forPeriodontal Regeneration andApplications in DentistryBioactive glasses were first developed by Hench et al. in 1969 in different forms, such as bulk, powder, composites, and porous scaffolds.able to bond to mineralized bone tissue in physiological environment

Composition and synthesis of bioactive glass nanoparticlesThe sol-gel-derived bioactive glasses, the composition of 60% SiO2, 36% CaO, and

4% P2O5 (by weight) has a high level of bioactivity,The synthesis of bioactive glass uses typical precursors like tetraethyl orthosilicate (TEOS), calcium nitrate (CN), and triethylphosphate (TEP).

Bioactive glass in dentistryuse as bone grafts, implant coatings, bone cements, toothpaste, and various other applications in dentistry.e.g-Bioglass, PerioglassBioactive glasses are known for osteoconductivity and bonding to bone through the release of ions and formation of a layer of apatite

BG: which type of graft?Autogenous- Allogenous- genetically different, same species

e.g- Iliac bone marrow, lyophilized bone graft, freeze-dried bone allograft(FDBA), decalcified FDBA..Heterogenous- both gene and species different.Alloplast- synthetics- e.g bioactive glass

Nanoparticles administered in Periodontal pockets

Cell therapy for periodontal regeneration is new optionPeriodontal ligament cells in direct contact with bioactive glass nanoparticles exhibited increased proliferation and cell viability and also an increase in alkaline phosphatase activity

Treatment of Dentinal Hypersensitivity

Bioactive glass nanocomposite applications in bone regeneration and dental implantsPeter et al. (2010) developed chitosan-gelatin/bioactive glass nanoparticles composite scaffoldsSowmya et al. (2011) synthesized and characterized -chitin hydrogel/bioactive glass nanoparticles nanocomposite scaffolds for periodontal regenerationJurczyk et al. (2011) synthesized and characterized nanocomposite Ti/45S5 Bioglass for use in dental implants

The future of bioactive glass nanoparticlesinjectable systems containing bioactive glass nanoparticles (the hydrogel polymer systems) have many advantages:

(i) They have adequate permeability for the transport of cell nutrients and metabolites, (ii) they exhibit biocompatibility and biodegradability, and (iii) some formulations are thermoresponsive

The future of bioactive glass nanoparticlesBioactive glasses have ideal characteristics for drug delivery systems; they can carry an active dose of drug molecules to target sites without any leak and premature negative effect on other areas.

An indication of use of these systems in dentistry is the treatment of head and neck tumors that needs controlled release of drugs at specific sites

cells removed from the periodontal tissue,expanded and injected into the injured tissue.

Nano & Endo

Scope of Nanotechnology inEndodonticsClinical applications

Instrument Canal disinfection- Irrigants, Medicaments, Material Obturating, sealers, retro-fillingRepair and pulp regeneration

Instrument modificationsAdini et al. examined the effects of cobalt coatings with impregnated fullerene-like WS2 nanoparticles on file fatigue and failure of NiTi filesIn another study, the distal end of the file was modified by selective coating of endodontic files

Enhancement of canal disinfectionIrrigants- nanoparticle-based antimicrobial photodynamic therapy e.g. poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with the photosensitizer methylene blue (MB) and light against Enterococcus faecalis by transmission electron microscopy (TEM)The synergism of light and MB-loaded nanoparticles led to approximately 2 and 1 log 10 reduction of colony-forming units (CFUs) in planktonic phase and root canals, respectively

MedicamentsNanoparticulates such as chitosan (CS-np) and zinc oxide (ZnO-np) have been shown to possess significant antibacterial properties ( a significant reduction in the thickness of Biofilm)

Modifications on- Obturating materialsBioactive glass 45S5 is one of the recent nanoparticles used in endodontic therapy. It has amorphous nanoparticles of 20-60 nm in size.

nanohydroxyapatite crystals in 279 nm showed superior antimicrobial activity (Actinomyces naeslundii, Peptostreptococcus anaerobius, Porphyromonas gingivalis, Porphyromonas endodontalis, and Fusobacterium nucleatum) as well as minimal microleakage.nanocrystalline tetracalcium phosphate had

significantly higher antimicrobial potency in an agar-diffusion testModifications on- Sealers

Retro-filling and root-repair materialsMineral Trioxide Aggregate (MTA) has become the material of choice of retrograde filling

Factors influencing the bioactivity of the NTsSterilizationCell phenotypeProtein concentrationProtein distribution pattern

Nano & OMFS

Nanoceramics for Bone Regeneration in the Oral and Craniomaxillofacial Complex

Nanoceramics and bone repairporous hydroxyapatite (HA) and tricalcium phosphate (TCP) have been shown to have excellent osteoconductive properties, but their biodegradation is poorHA: nanometer-sized needlelike crystals of approximately 5-20 nm width by 60 nm length nanOsss bone void filler, Ostims

Nanomaterials is superior to conventional mat: for bone regenerationNanotechnology for craniofacial bone and cartilage tissue engineering

Nanotechnology for craniofacial bone andcartilage tissue engineeringDue to the biomimetic features and excellent physicochemical properties, nanomaterials have been shown to improve adhesion, proliferation, and differentiation of cells, which would finally guide tissue regenerationSynthetic and natural polymers are excellent candidates for bone/cartilage tissue engineering application due to their biodegradability and ease of fabrication

Nano & Oral Medicine

Nanoparticles preparation methods

Saliva- our friend

Saliva as a biofluid for disease detection

Applications of Micro Electromechanical Systems (MEMS)Nano Electromechanical Systems (NEMS) in salivary diagnostics

Nanorogel & Nanorobot

Nanogel for Local AnaethesiaNanogels are probably one of the best candidates due to the lesser pain during injection and longer blood circulation time.Tan et al. reported the nanogel systems for LAs such as bupivacaine poly(DL-lactide-co-glycolide) nanospheres, procaine hydrochloride (PrHy) hydrogel delivery systems and showed that the drug release can be delayed over 7-15 h

Nanorobots -Curing the hypersensitivityMicroscopic studies reported earlier show that when dentin is exposed for 5 min to fluids like red and white wine, citrus fruit juices, apple juice, and yogurt, they remove the smear layer and open up dentinal tubulesthe construction of reconstructive dental nanorobots, using native biological materials, could selectively and precisely occlude specific tubules within minutes, offering patients a quick and permanent cure

Nanorobotic dentifricesa caries vaccine may be available in near futureDentifrice robots would also provide a continuous barrier to halitosis, since bacterial putrefaction is the central metabolic process involved in oral malodorArtificial phagocytes called microbivores could patrol the bloodstream, seeking out and digesting unwanted pathogens including bacteria, viruses, or fungi

Challenges of biomaterialsThe successful use of biomaterials presents numerous challenges. A major one is the issue of maintenance, and in particular that most devices are implanted well into the body and therefore not freely available for inspection or repairLife expectancy in the wealthier parts of the world is now of the order of 80 years, which means that many people now outlive (overstay) the useful life of their own connective tissue

Toxicity of nanoparticles1. Cytotoxicity of one or more of the nanoparticle constituents which is an inherent property of the chemical compound2. Cytotoxicity of one or more of the degradation products of the nanoparticle constituents3. Endocytosed nanoparticle-mediated apoptosis (cell death)4. Nanoparticle-mediated cell membrane lysis

Nanoparticle Cytotoxicity to Mammalian Cells

ReferencesChemistry of Medical and Dental Material by John W. Nicholson (2002)Dental biomaterials- Imaging, testing and modelling by Richard Curtis (2008)Nanobiomaterials in Clinical Dentistry by Karthikeyan Subramani (2013)Advanced Biomaterials and biodevices by Ashutosh Tiwari ( 2014)

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