Nano-technology in restorative dentistry and dental caries management

1. Nano Technology in restorative
dentistry and Dental caries managment
Prepared by :
Ali Alarasy Ala’a Alkhtani
Barkat Altayar Mohammed Alwarafi
Hayel Abdul-wasai Mohammed Abul-Regal
Murad Aldahnon Yacob Alsarem
Abdul-Rahman Talbah Kais Alhetar
Bassam Alshagdari
Supervision :
Dr. Adel Alademi

2. introduction
• Nanotechnology has been defined as the creation of functional
materials, devices, or systems through control of matter on the
nanometer scale (1-100 nm).
• Currently, nanotechnology is experiencing rapid growth, with
many potential applications in dentistry.
• Nanotechnological developments for remineralization of
incipient caries lesions as well as biomimetic strategies for
enamel synthesis based on the application of nanotechnology.

3. • In recent years
, biomimetic treatment of early caries lesions by the application
of various types of nano-sized hydroxyapatite
or calcium carbonate has also received considerable attention.
• Nanotechnology has been applied to dental materials as an
innovative concept for the development of materials with better
properties and anticaries potential.

4. the focus will be on 3 topics:
• remineralization of initial caries lesions.
• caries-preventive nanofillers added to resin composites.
• strategies for biomimetic synthesis of enamel for repair of caries
with enamel-like nanomaterials.

5. Remineralization Of Initial Caries Lesions:
• Several nanotechnological approaches have been reported for
remineralization of early caries lesions. Case in phosphopeptide
amorphous or calcium phosphate nanocomplexes have been
shown to promote enamel remineralization and provide anti-
cariogenic activity in laboratory, animal, and human
experiments.

6. Caries-Preventive Nanofillers In Restorative
Materials
• Secondary caries and restoration fracture are still the main
reasons for dental restoration failure, thus limiting the longevity
of (resin composite) restorations To control caries-induced
demineralization at the resin composite-tooth interface, calcium
and phosphate ion-releasing nanofillers have been developed
Apparently, not only the size of the apatite nanoparticles used
for remineralization purpose but also the pH of the
remineralizing agent will affect the process of mineralization.

7. Nanomechanical properties of dental resin-
composit
• Composite is the most widely used and versatile dental material
used for restoring dental cavities, especially because of its
capacity to mimic natural tooth appearance. It is a multi phase
substance composed of four major components: resin (organic
polymer matrix); filler (inorganic) particles; coupling agent
(silane); and the initiator-accelerator of polymerization.
• Nanocomposites containing 40% nanoparticles of amorphous
calcium carbonate have been shown to rapidly neutralize a lactic
acid solution of pH 4.0 by increasing the pH to 5.69 within 10
min.

8. • The mechanical properties of the calcium- and phosphate-
releasing experimental composites match those of commercial
hybrid Composites.
• In addition, fluoride release from restorative materials has been
considered to inhibit tooth demineralization and caries
development.
• The addition of CaF2 nanoparticles (50-60 nm) to resin
composites results in fluoride release similar to or even higher
than that from commercial resin-modified glass-ionomer
materials with high flexural strength and sustained fluoride
release may have the potential to reduce restoration fracture
and secondary caries.

9. • For a series of Bis-GMA/TEGDMA composites, the elastic
moduli and nano-hardness of the resin-composites increased
systematically with increasing filler loading.
• Bulk-fill and flowable resin-composites exhibited some what
lower group average elastic moduli and nano-hardness than
those of conventional hybrid resin-composites.
• For the resin-composites studied, there was a strong correlation
between elastic moduli and nano-hardness.
• Varying the unloading rates showed no consistent effect on the
elastic moduli and nano-hardness.

10. Biomimetic Synthesis Of Enamel–Repair
Of Caries Lesions With Enamel-LinkNanomaterials:
• Due to its non-regenerative nature, enamel is unable to heal and
repair itself after demineralization of the surface and
subsequent cavitation. Biomimetic strategies for artificial
enamel formation might have the potential to repair enamel
surface damage and increase the longevity of teeth.

11. Nanotechnology has promoted the development of bio-inspired
routes for caries prevention and tooth-surface repair (Hannig and
Hannig, 2010).

12. • Functional materials or structures at the nanometer scale (0.1–
100.0 nm) can be used to control the formation of cariogenic
oral biofilms.
• nanoparticles can deliver antibiotics and bioactive compounds.

13. Nanotechnology-based strategies for dental
caries management
1. Antibacterial approach
2. Remineralizing approach
3. Toxicity and possible biologic impacts

14. 1. Antibacterial approach
• Nanoparticles of metals (i.e., silver and zinc) and antimicrobial
• polymers have gained significant interest over the years dueto
their remarkable antimicrobial properties.
• The excellent antibacterial effect of these nanostructured agents
is mainly attributed to the high surface area to volume ratio
enabling greater presence of atoms on the surface, which
provides maximum contact with the environment.
• In addition, the small size of these particles makes penetration
through cell membranes easier, thus affecting intracellular
processes resulting in higher reactivity and antimicrobial
activity.

15. Silver nanoparticle
• Silver nanoparticles (NAg) have been used in a wide range of
antimicrobial applications such as wound dressings, implant
coatings, and others.
• The antimicrobial action of silver may be proportional to the
amount of released bioactive silver ions (Ag+) and their
interaction with bacterial cell membranes.

17. Zinc oxide nanoparticles
• Similar to silver, zinc oxide (ZnO) has demonstrated
antibacterial effects against several types of bacteria, including
S. mutans.
• Nano-ZnO particles (NZn) have been found to be more effective
than conventional particles against Gram negative and positive
bacteria.
• The antibacterial mechanism of NZn is credited to modified cell
membrane activity and oxidative stress; these generate active
oxygen species such as H2O2 that inhibit growth of planktonic
microbes Gram.

18. Quaternary ammonium polyethylenimine
nanoparticles
• Quaternary ammonium polyethylenimine (QAS-PEI)
nanoparticles were incorporated in restorative materials to
improve antibacterial activity and reduce adverse effects on
mechanical properties further.
• the advantage that the antibacterial agent is copolymerized with
the resin by forming a covalent bond with the polymer network.
• therefore is immobilized in the composite and not released or
lost over time.

20. 2. Remineralizing approach
• The induction and modulation of biologic activity are the
functions proposed for anticaries restorative materials such as
fluoride or other agents affecting the de/re mineralization
balance.

21. Amophous calcium phosphate
nanoparticles
• ACP is easily transformed into crystalline phases such as
octacalcium phosphate and apatite as a result of
microcrystalline growth.

23.  Results
• NCP nanocomposite released Ca and P ions and the release
significantly increased at cariogenic low pH Biofilms.
• NCP nanocomposite contained higher Ca and P ions.
• but much less lesion around NCP nanocomposite.

24. Calcium fluoride nanoparticles
• Fluoride has documented caries-inhibiting effects.
• inspired a continuous search for improvement in the
performance of fluoride releasing restorative materials.
• The resulting composite exhibits high fluoride release but still
maintains strength and wear resistance.

25. Nanohydroxyapatite and
Nanofluorohydroxyapatite
• Synthetic hydroxyapatite (HA) is a biologically compatible
material, and is considered a logical compound substitute for
the natural mineral constituent of dentin.
• Its applicability in biomaterials by the addition of HA powders
to restorative dental materials for remineralization effects and
improvement of mechanical properties has been investigated
due to its excellent biocompatibility and bioactivity.

27. Dental adhesives :
• the concept of “minimum interventions” or “mini-mally invasive
cavity preparations” has been widely accepted which means that the
diseased dental tissues is only removed and replaced with adhesive
restorations.
• One-step that modify the smear layer.
• Two-step was the total removal of the smear layer.
• Three-step was the adhesive that dissolved the smear layer.
• These adhesives utilize acidic “self-etching primers” that dissolve the
smear layer making it a part of the hybrid layer.
• three-step etch-and-rinse adhesive is considered the “gold standard”
regarding its clinical durability.

29. Glass ionomer cement
• GIC commonly known as polyalkenoate cement is water-based
cement and formed by the reaction of an acidic polymer and a
basic glass in the presence of water
• HA has been incorporated in GIC powder to improve its
biological and mechanical properties.
• Glass ionomer is the only material that has the self-adhering
property.

30. Nanorobotic oral prophylaxis.

31. Future prospective of nanotechnology in the
field of adhesive dentistry :
On-demand antibacterial adhesives containing TiO2 nanoparticles,
initiated by UV irradiation, proved to interfere with bacterial activity.
• Also TiO2 nanoparticles containing adhesives were found to have the
potential of tooth remineralizationin simulated body fluids.
• This could open up the potential to create dental adhesives that
reduce the incidence of secondary caries and promote closure of gaps
forming at the interface toward the tooth via remineralization of
adjacent tooth substance as well as prevention of bacterial infections
via on-demand UV irradiation.

32. Improving adhesive polymerization through catalytic activity of
nanoparticles.
• as a pretreatment to dentin after acid etching and before
adhesive application to improve the resin polymerization
resulting in enhanced bond strength
Antibacterial orthodontic adhesives containing nanosilver.
Radiopaque dental adhesives Modern composite-filling
materials commonly contain radiopaque components.
• nanofilled adhesive had radiopacity better than enamel and
dentin without adverse effect on bond.

33. Self-adhesive composites
• flowable composites containing adhesive mono- mers such as
Vertise Flow (Kerr) and Fusio Liquid Dentin (Pentron Clinical
• Self-healing adhesives
• When cracks are initiated in the polymer, the capsules rupture
and healing monomers fill the crack and polymerize there
allowing healing of the crack.

34. 3. Toxicity and possible biologic impacts :
• Nanoparticles must selectively kill bacteria without imparting
toxicity on mammalian cells

35. References
• Nanomechanical properties of dental resin-composites - El-Safty S1, Akhtar R, Silikas N,
Watts DC.
• Nanobiomaterials in Clinical Dentistry - Karthikeyan Subramani, Waqar Ahmed, James
K.Hartsfield, Jr. Nano.
• Systemic review article of Stabilized zirconia as a structural ceramic : an overview.
• Nanocomposite containing amorphous calcium phosphate nanoparticles for carires
inhibition – Hockin H.K, Jennifer L. Moreau, Limin Sun, Laurenece C. Chow.
• Novel calcium phosphate nanocomposite with carires-inhibition in a human in situ model
– Mary Anne S. Melo, Michael D. Weir, Lidiany K.A. Rodrigues, Hocjin H.K.
• Review Article of Nanorobotics in dentistry – Santosh Kumar Verma, Rashi Chauhan.