dental chemistry

1. Dental Chemistry
Dr. Muthana A. Al-Shemeri
PhD Clinical Biochemistry
College of Medicine,
Otago University,
New Zealand

2. •Inorganic nanoparticles in dentistry
• DR. MUTHANA A. AL-SHEMERI
• 9/2/2022
Lecture 6

3. A nanometer is a unit of length in the metric system, equal
to one billionth of a meter (1×10−9 m).

4. The term nanoscale is used to refer to objects with dimensions
on the order of 1-100 nanometer.
Radius in nm

5. •Properties of nanoparticles
At the nanometer-length scale, materials behave
differently due to the increased number of atoms near the
surface compared to the bulk structure.
The smaller a particle, the greater in its surface area to
volume ratio and the higher its chemical reactivity and
biological activity.
The greater the biological reactivity of nanomaterials
results in increased production of reactive oxygen species
(ROS) that have potent antimicrobial effect.

6. However, the same properties that make nanoparticles so
unique-that is, primarily, their small size, large surface area,
chemical composition, solubility, and geometry-could also
be responsible for their potential hazard to human health.

7. •Synthesis of nanomaterials
Two types of approaches for the synthesis of nanomaterial and fabrication of
nanostructure are known
1.Top-Down refers to successive cutting of bulk material to gain nanoparticles.
2.Bottom-up refers create nanoparticles by self-assembly.
Chemical synthesis is a good example.

8. •Nanotechnology is the production of functional materials
and structures in the nanoscale using various physical and
chemical methods with about 1-100 nm length scale.
•Since nanoparticles have dimensions well below the
wavelength of visible light (400-800 nm), they cannot
scatter the particular light resulting in inability to detect the
particles by naked eye.
•This has tremendous implications for controlling the optical
properties of materials containing these particles.

9. New potential treatment opportunities in dentistry may include different
approaches:
a)Building up particles by combining atomic elements: i.e., bottom-up approach.
This is applied in local anesthetics, orthodontic treatment, diagnosis and treatment
of oral cancer.
b)Using equipment to create mechanically nanoscale objects:
i.e. top down approach. Examples include nanocomposites, impression materials
and bone replacement materials.

10. Most recently nanoparticles have been used in the development of new dental
materials to increase antibacterial action.
Metals have been used for centuries as antimicrobial agents, but nanoparticle
metals have gained significant interest due to their important antimicrobial
properties, such nanometals as:
(1)Silver (Ag).
(2)Gold (Au).
(3)Metal oxides, such as titanium oxide, zinc oxide (ZnO) and amorphous
calcium phosphate nanoparticles.

11. •Ag nanoparticles:
Ag nanoparticles can inhibit microorganism growth on the tooth
surface when added to adhesives and primers .
Ag nanoparticles can also decrease the metabolic activity of the
microbial cells. When Ag nanoparticles used to modify dental
materials, it leads to significant improvements in the mechanical
properties and color stability of these materials.

12. •Zinc oxide nanoparticles:
ZnO nanoparticles are among the most advanced new dental materials,
exhibiting an antibacterial effect by direct contact in bacterial biofilms.
ZnO nanoparticles also have antibacterial effects when incorporated in
composite resins.
The antimicrobial property of the ZnO nanoparticles was found (similar to
Ag) to be due to the production of reactive oxygen species (ROS) leading
to destruction of the bacterial cell components.

13. Titanium dioxide nanoparticles
Composite resins, orthodontic resins, dental adhesives, and glass
ionomer cements, all containing TiO2.
Calcium carbonate nanoparticles
The use of toothpaste containing nanosized calcium carbonate
enabled better remineralization of early enamel lesions.

14. Thank you