Crowns – when a filling is no longer sufficient

Crowns are a fixed dental prosthesis for major damage caused by caries, or an accident that can no longer be repaired with a filling. They owe their name to the fact that they usually vault the biting surface. In the process, the original contours of the tooth, such as the cusps in the crown, are reproduced to enable a perfect bite. In essence, a distinction is made between replacement, anchoring and protective crowns, which in turn can be produced from different materials.

When referring simply to ‘crowns’, we usually mean replacement crowns. They take over the function of a filling by replacing a larger part of the tooth. If the entire biting surface of a tooth stump is covered, we talk about ‘full’ crowns; otherwise, ‘partial’ crowns. In the case of the latter, it is not always clear when it is still an inlay filling and when it is already a crown.

Anchoring crowns are usually used to support a bridge. In this scenario, the teeth adjacent to the gap are fitted with crowns to attach the bridge to them. Removable dentures can also be supported by crowns. These so-called ‘telescopic’ or ‘double’ crowns are attached to tooth stumps on one side and to the denture on the other. If the two matching crowns are now slid over each other, the prosthesis is held stable by frictional resistance. Finally, protective crowns are used as ‘armour’ for exposed dentin when the hard enamel has been lost (usually caused by acid erosion).

The way crowns are attached to remaining tooth substance depends on the material used. Cement or plastic adhesives are used as standard, but in the case of severely damaged teeth, crowns can also be fixed with a pin. In this scenario, root canal treatment (endodontics) is necessary beforehand.

Materials: preferably ceramic

Ceramic and metal – especially gold – are the materials mainly used for crowns. The desired solution for most patients is an all-ceramic crown, as it is practically indistinguishable from a natural tooth. The only disadvantage is that a ceramic crown must be slightly thicker than a metal crown in order to have comparable durability. This means that more of the tooth may need to be ground down for the crown to fit. In addition, a pure ceramic crown costs more than partially-metal alternatives.

A gold crown may be cheaper, but it is only suitable for non-visible areas and is increasingly considered by patients to be an aesthetic no-go. In terms of fracture stability and body compatibility, both ceramic and gold crowns meet the highest standards.

The veneer crown represents a middle ground between these two materials. In this instance, a metal or gold crown is covered by a tooth-coloured layer of ceramic or (more rarely) plastic. A narrow metal strip often remains visible at the gumline. For the sake of completeness we should also mention plastic crowns – though they barely play a role in dentistry and are mainly used for temporary restorations.

In order to be able to make a crown, we hold an initial appointment to take an impression of the tooth due to be restored. To do this, destroyed tissue must first be removed and, if necessary, a build-up filling must be inserted. For pure-ceramic and veneer crowns, the tooth’s shade is also determined. Then, while the crown is being produced in the dental laboratory, the patient wears a temporary crown. At a second appointment, the crown is put in place and bonded, after which minor adjustments can be made to achieve a perfect fit.

We will be happy to advise you on an individual basis regarding your options.