Introduction
Teeth destroyed by caries cannot be rebuilt by the organism. The defects must be closed by a filling. Unfortunately, the term seal is often used as a synonym for the filling.
This word is derived from the Latin term for lead, and lead really has no place in the oral cavity. Therefore this erroneous designation should finally disappear from the vocabulary. A filling can also be necessary, for example, if a piece of a cheek tooth is broken off.
What is a seal ?
The term seal is a colloquial term that describes a dental filling made of amalgam. The word comes from a time when amalgam fillings were primarily placed. The origin of the word is the Latin word “plumbum”, which means “lead” in English.
Although amalgam fillings are hardly ever placed, the word is wrongly used by a large part of the population to describe a filling, regardless of the material. The placing of an amalgam filling used to be called “sealing”. However, the term is no longer contemporary. Furthermore, the word seal is also used outside of dentistry to refer to a lead seal for containers and housings. This seal indicates whether the object has been opened.
What materials are available for a dental filling?
Overview of the different filling materials Composites (plastic) Amalgam Gold (as inlay) Ceramics (as inlay) Cements (e.g. glass inomer cement) Compomers (plastic)
- Definitive dental filling materials: Composites (plastic) Amalgam Gold (as inlay) Ceramics (as inlay)
- Composites (plastic)
- Amalgam
- Gold (as inlay)
- Ceramics (as inlay)
- Composites (plastic)
- Amalgam
- Gold (as inlay)
- Ceramics (as inlay)
- Temporary tooth filling materials: Cements (e.g. glass inomer cement) Compomers (plastic)
- Cements (e.g.
glass inomer cement)
- Compomers (plastic)
- Cements (e.g. glass inomer cement)
- Compomers (plastic)
Silicate cement has been used for years to fill the front teeth. It was available in different colors, so that it could also meet the aesthetic requirements. However, the polishability was not optimal because silicate cement has a relatively rough surface.
Also the durability of such fillings was not very good, with time small particles broke out. Stone cement was available for the posterior region. A very resistant filling material and an alternative to amalgam.
However, silicate cement and stone cement are no longer used today, as there are better alternatives. Amalgam has been used as a filling material for the posterior region for many years. This combination of mercury and silver filing is easy to process as a plastic material, is easy to model and, once hardened, withstands chewing pressure.
However, amalgam has been discredited because of its mercury content, which is not justified. The minimal absorption of mercury is far exceeded by some food products. Vapors of mercury used to be produced when mixing amalgam because it was done in a mortar.
Today, however, the mixing is done in closed capsules, so that this danger no longer exists either. However, tooth-colored fillings are not possible with amalgam. Composite is a filling material consisting of an organic plastic base, matrix, with inorganic fillers.
Since silicate cement did not quite meet the requirements of a filling material, alternatives were sought. Initially, experiments were conducted with pure plastic. The fillings were ideal for polishing, but had the disadvantage of shrinking when setting and changed color over time.
Therefore, the plastic was mixed with finely ground glass or ceramic particles to reduce shrinkage. This composite, known as macrofiller, with a grain size of 5m made polishing difficult because it had a relatively rough surface. The next step was the installation of silica, so-called microfillers with a particle size of 0.2m.
This resulted in a much higher filler content, but very good polishability did not significantly reduce shrinkage and was not sufficiently abrasion resistant. The latest development is the hybrid composite. It combines larger fillers with microparticles in the spaces between the macroparticles.This has reduced the proportion of plastic even further, which does not completely eliminate polymerization shrinkage but further reduces it.
If the material had to be mixed from two components first, the introduction of the light-curing composite eliminated the need for mixing and significantly reduced the setting time. In order to improve the connection with the enamel and thus avoid the marginal gap, a processing system was developed that ensures an intimate connection between the filling and enamel. For this purpose, the enamel margin is etched with phosphoric acid and after rinsing with water, an adhesion promoter, called bonding agent, is applied and only then the final filling is placed.
Glass ionomer cement is less suitable as a filling material because it has a lower abrasion resistance and is difficult to polish. In addition to its use as an underfilling material, it is also used to cement dental crowns. The advantage of glass ionomer cement is that it chemically bonds with the hard tooth substance.
Probably the best restoration of a posterior tooth cavity is the inlay. Inlays are made of either gold or ceramic. They are manufactured outside the oral cavity in the dental laboratory.
This requires an impression to be taken after the cavity preparation. The cavity must not show any areas that are underneath each other, so that the finished inlay can be inserted without difficulty. The inlay is cemented in with phosphate cement or glass ionomer cement.
A stable, abrasion-resistant restoration of cavities in the posterior region is achieved with a gold or ceramic inlay. Compared to gold inlays, ceramic inlays have the advantage of matching the color to the tooth. In contrast, the stability of a gold inlay is better.
However, the restoration of a cavity with an inlay requires much more effort, which is of course also reflected in the price. In addition to the gold inlay, the gold hammer filling is the best way of restoring a cavity with a filling. This method of tooth filling is very old, but it is hardly ever performed today.
In contrast to the inlay, this filling is done directly in the tooth. Gold foil or sponge gold is used, both are inserted in portions into the usually small cavities with a stuffing instrument. The individual layers are joined together by the stopper, thus creating a filling with an ideal marginal design. Due to the great amount of work involved, this type of filling therapy is only rarely used and is also very expensive, since only pure gold and no alloy can be used. However, the durability of such fillings is very high.
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