Full Coverage Aesthetic Restoration of Posterior Primary Teeth
Pre-veneered Stainless Steel Crowns

Pre-veneered stainless steel crowns resolve some of the problems associated with stainless steel crowns, open-faced stainless steel crowns, and composite strip crowns. They were introduced in the mid 1990s. They are aesthetic, placement and cementation are not significantly affected by hemorrhage and saliva, and can be placed in a single appointment. The stainless steel crown is covered on its buccal or facial surface with a tooth colored coating of polyester/epoxy hybrid composition.

Pre-veneered stainless steel crowns are available from various manufacturers, i.e., Kinder Krowns, Mayclin Dental Studios, Minneapolis, MN; Dura Crowns, Space Mainttiners Laboratory, Van Nuys, CA; NuSmile Primary Crowns, Houston, TX; Cheng Crowns, Peter Cheng Orthodontic Laboratories, Philadelphia, PA.

Advantages

• They are aesthetically pleasing.
• They require relatively short operating time.
• They have the durability of a steel crown.

Disadvantages

• They take longer to place than stainless steel crowns.
• They are 3 times more expensive than stainless steel, ($17 vs $6).
• The technique does not allow for major recontouring and reshaping of the crown.
• The tooth is adjusted to fit the crown, rather than adjusting the crown to fit the tooth.
• As crimping is limited to lingual surfaces; there is not close adaptation of crown to tooth.
• There are reports of the veneer facing fracturing; however, it can be easily repaired using the open-faced, stainless steel crown technique.

Technique

• Prepare the tooth as for a standard stainless steel crown; however, more circumferential tooth reduction is required.

• Unlike the stainless steel crown, the pre-veneered crown only allows crimping of the metal lingual margin of the crown; therefore, it is necessary to refine the prep to fit the crown.
• Do not force the crown on the tooth.
• A properly fitted crown has a passive fit.
• The crown should extend 1 mm past the gingival margin.
• The length of the crown is altered by trimming the gingival margin with a diamond bur and water spray.

• The lingual aspect of the crown may be crimped slightly with a 137 Gordon plier.

• Too much crimping of the metal substructure may cause fractures in the veneer material.
• The crown is cemented with glass ionomer cement.

• The excess cement is removed and the occlusion is checked. Only minimal occlusal reduction is allowed, as the veneer will weaken.

• Cold sterilization in glutaraldehyde is recommended.
• A number of studies have shown most veneers fracture by twelve months resulting in an unaesthetic appearance. Two techniques may be used to replace the veneer on the crown. One technique is similar to the previously described technique for fabricating the open-faced, stainless steel crown. An alternative technique is sandblasting/roughening the labial and occlusal surfaces of the existing stainless steel crowns with an abrasive powder or diamond stone, application of a bonding agent and a composite. Both repair techniques showed similar results in appearance and longevity.^8-11