Dental Materials in Materials Science

Study Notes

Materials Science seeks to explain the properties and performance of materials by examining their internal structure
Materials Science is a combination of chemistry, physics, and engineering
Dental Materials is a subgroup of materials science
Dental Materials are part of the field of biomaterials
Dental Materials are also known as Dental Biomaterials

Ancient practices involved using materials for aesthetics
Early materials included ivory, porcelain, wax and zinc oxide eugenol
By the 1800s, dentistry became a scientifically based discipline and the pace of development for materials quickened.
Amalgam, a silver filling material, was widely accepted and frequently used
Porcelain was also used for inlays and crowns
Now, new ceramic materials and processing technologies have been adapted in dentistry
The pace of new dental material development is rapid
The basic concepts of materials science and their use do not change.
Dentists need to understand the behavior of the materials they use to select products from a long list of possibilities.

Teeth and restorative materials need to be stronger than the food we eat
Properties of materials are a result of atomic bonds.
Atoms of materials are held together by two types of atomic bonds: primary and secondary.
Primary Bonds involve the transfer or sharing of electrons between atoms.
- Ionic Bonds: Result when an electron is given up by one atom and accepted by another. The positive and negative ions attract each other by the electromagnetic force to create an ionic bond.
- Covalent Bond: Formed when two atoms share a pair of electrons.
- Metallic Bond: Involves sharing many electrons by all the atoms in the material.
Materials are classified into three categories based on their primary atomic bonds:
- Metals: Ductile and retain strength when bent due to metallic bonds
- Ceramic Materials: Strong when compressed, but weak and brittle when pulled or bent, due to ionic bonds.
- Polymers or Plastics: Range of properties due to covalent bonds and secondary bonds in their atomic structure.
Composites are a combination of two solid materials and can be considered a fourth category.
- Enamel is a composite of apatite (a ceramic material) and protein (a polymer).

Dental materials properties should be tested in specialized labs before clinical use to check the suitability of the material for its intended application.
Density: The amount or mass of a material in a given volume. Common unit of density is g/cm³. Lightness is nearly always an advantage in restorative materials, but sometimes heavy materials are employed (sometimes tin or lead is used in a full lower denture to control movement).