8.7.3 Stainless-steel crowns
Stainless-steel crowns should be considered whenever posterior primary teeth
(especially first molars) require restoration. They were originally developed to
provide a 'restoration of last resort' for those teeth that were not salvageable by any
other means. At the time that they were introduced in the early 1950s the only
alternatives were silver or copper amalgam or a selection of cements, materials
completely unsuited to the restoration of grossly carious teeth or those that had been
weakened by pulp treatment. Over the years, it has become apparent that the life
expectancy of these crowns is far better than any other restoration for primary
posterior teeth and that they come close to the ideal of never having to be replaced
prior to exfoliation. In addition, they are less demanding technically than intracoronal
restorations in primary teeth.
They should therefore now be considered for any tooth where the dentist cannot be
sure that an alternative would survive until the tooth is lost. It is unfair to put a child
through more treatment situations than necessary because a less successful material,
which needs frequent replacement, was chosen.
The indications for stainless-steel crowns are shown in 358HTable 8.2.
The technique
Wherever possible local anaesthesia should be given, although in certain situations,
for example, while preparing a non-vital tooth, this is not always necessary.
Nevertheless, even in these teeth there will need to be some tooth preparation
involving the gingival margin, which can cause some discomfort for which local
anaesthesia is advisable. It is sometimes possible to use only a topical anaesthesia,
such as a benzocaine ointment on the gingival cuff. In other instances, when the
preparation for a crown is carried out at the same visit as a pulpotomy, local analgesia
would already have been administered. Where crowns are being fitted because of
extensive cavities or decalcification, a rubber dam is advisable, even though the
authors acknowledge that the use of rubber dam for restorations in children in general
dental practice is quite low.
Prior to preparation, all caries is removed and any pulp treatment that may be required
carried out. A recent preoperative radiograph must be available to make sure that the
periapical and interradicular tissues are healthy and that the tooth is unlikely to be
exfoliated in the near future.
Preparation and fitting is easier if rubber dam is in place but even if this is not the case
it is advisable to place wedges mesially and distally, gingival to the contact area (359HFig.
8.13 (a)). These wedges should be placed firmly using the applicator supplied with
them or a pair of flat-beaked pliers. It is essential that good soft tissue anaesthesia be
obtained so that this procedure is not painful, although the wedges should compress
the gingivae away from the contact area and not be driven into the tissue. The use of
wedges in this manner protects the tissues and reduces the contamination of the
operating field as well as making the margins of the preparation easier to see. The
mesial and distal surfaces of the tooth are removed using a 330 bur or a fine tapered
fissure bur or diamond (360HFig. 8.13 (b)). It is important to cut through the tooth, away