A posterior tooth can be protected by an aluminum provisional crown. These are available in a wide range of sizes. Always remember that crowns tried and not used must be sterilized before reuse. You may need to use a millimeter ruler to determine the size, measuring the mesial-to-distal distance.
Table 7. Steps Using an Aluminum Shell
|1.||Once you have found the appropriate size, try it on the tooth to make sure the distance between contacts is correct.|
|2.||See how much is necessary to trim at the gingiva. If the crown is 2 mm above the adjacent teeth, then you would trim 2 mm all around at the gingiva using a crown scissors. It is important to trim in a smooth manner so as not to leave sharp or uneven edges that can irritate the gingiva.|
|3.||Use contouring pliers to crimp the margins of the crown inward (Contouring pliers Nos. 112, 114 and 115 are most common.) Using the contouring pliers helps in adapting the crown to the finish line. It is possible to omit the contouring and reline the shell with methylmethacrylate (self curing acrylic). This will give you a better internal fit and more exact margins and is probably preferable since it helps avoid a metal overhang.|
|4.||Once the crown is seated on the prepared tooth, instruct the patient to bite down normally. This helps establish an initial occlusal anatomy onto the soft aluminum shell.|
|5.||Further check the occlusion with articulating paper and make adjustments.|
|6.||Check crown for rough metal margins. These can be smoothed using sandpaper, discs or a rubber wheel.|
- If you don’t reline the aluminum crown with acrylic, cement it using IRM or Zinc Oxide Eugenol (ZOE).