Plastic fillings

Polymerisation lamp
Etching technique and completed filling

Plastic filling materials are inserted in the cavity in soft or pliable condition.

Subsequent hardening occurs spontaneously because the material was previously mixed with various counter-activating components or the bonding reaction was triggered through light energy.


Composites consist of a basic plastic component (matrix) and filling material particles (tiny silica beads or chips). The plastic causes the integration of the filling, while the filling material prevents premature abrasion (abrasion stability). Light effected hardening has almost completely replaced the two-component variant (blending procedure). The unsurpassed advantage of modern composites is the fact that the colour of the filling can be perfectly adjusted. A disadvantage is polymerisation shrinkage, during which the material contracts slightly.


Glass ionomer cement is created by mixing organic acids (polyacrylic acid) and finely ground glass. It is very solid but unfortunately also brittle and is therefore not suitable for fillings which have to absorb chewing pressure. It is very suitable for stump development or poured fillings before crowning, as underfilling for composites and as long-term provisional prosthesis. Glass ionomer cement bonds with the dentin and enamel for form a chemical compounds and therefore adheres well on the hard dental substance. Silver-particle enhanced glass ionomer cements form a sub-group called cermet cements. Their colour is silver-grey while normal glass ionomer cements are available in various dental colours.


Compomers.
This material class developed from composites and glass ionomers. It basically consists of modified composite materials. Its properties are similar to those of composites. The fillings achieve a good boundary density with the adhesion technique.

Ormocers. The term stands for organically modified ceramics. Like composites and compomers, ormocers contain a plastic matrix and the finest filling materials. They are tooth coloured and are attached to the tooth with the adhesion technique. Ormocers contain an organic as well as an inorganic network. This distinguishes them from composite materials, although processing and appearance are similar.

Amalgam capsule system
Processing amalgam

Amalgam. Chemically, amalgams are mercurial alloys with other materials. If heated to a temperature above –38.9°C, mercury is a liquid metal, forming a compound when in contact with other materials. To form dental amalgam, equal parts of mercury and a powdered alloy –with silver as a main component – are used. Copper, tin and zinc may also be contained. They are mixed in mixing devices after pre-dosage. Safer processing is provided by capsule systems, in which the respective amounts of powder and mercury are already contained. The development of Non-Gamma-2-Amalgam improved the material properties, and corrosion phenomena such as blackening and porous surfaces were repressed.


Considered from a material-technical point of view, amalgam has ideal properties as side tooth filling material:

  • About the same hardness and equal abrasion behaviour as the enamel,
  • High pressure stability,
  • Dimensional stability during the hardening process,
  • Smooth transition to the tooth,
  • Good processing properties.

Amalgam handling characteristics:

  • Insertion and removal of amalgam fillings should be avoided in pregnant and lactating women. Indication in children should be verified carefully.
  • Severe kidney dysfunction is a relative contraindication.
  • Hypersensitivity proven by an allergy test excludes the use of amalgam.