496H
Fig. 9.41 Caries and further breakdown
around an amalgam in a hypomineralised
molar.9.11.1 Preformed metal crowns (stainless-steel crowns)
The advantages of these are:
- Single visit for placement.
- Relatively quick and simple procedure.
- Usually reduce sensitivity totally, because they cover the whole tooth.
- Inexpensive compared with cast restorations.
- Good retention rate.
The disadvantages are:
- Require more tooth preparation than cast preparations.
- Once a tooth has been prepared for a stainless-steel crown, it will need a full
coverage restoration eventually. It has been suggested that placing orthodontic
separators 1 or 2 weeks prior to preparation reduces the amount of tissue requiring
removal. However, some reduction is usually necessary. - Gingival margins are sub-gingival.
Operative technique
- Obtain adequate anaesthesia.
- Isolate the tooth to be crowned.
- Select the crown size.