Open-faced Stainless Steel Crowns

Advantages

  • The aesthetics are good but not great (the metal shows through the composite facing).
  • They are very durable, wear well and retentive.
  • The materials are fairly inexpensive.

Disadvantages

  • The time for placement is long as it involves a two-step process (crown cementation/composite facing placement.
  • Placement of the composite facing may be compromised when gingival hemorrhage or moisture is present, or when the patient exhibits less than ideal cooperation.

Technique

  • Once the cement in the stainless steel crown is set, cut a labial window in the cemented crown using a no. 330 or no. 577 bur.
labial window in crown
  • Extend the window:
    • Just short of the occlusal edge.
    • Gingivally to the height of the gingival crest.
    • Mesio-distally to the line angles.
extend window in crown
  • Remove the cement to a depth of 1 mm.
  • Place undercuts at each margin with a no. 35 bur or with a no. ½ round bur.
  • Smooth the cut margins of the crown with a fine green stone or white finishing stone.
smooth cut margins
  • After using a glass ionomer liner to mask differences in color between remaining tooth structure and cement, place a layer of bonding agent.
  • Place resin based composite into the cut window forcing the material into the undercuts and polymerize.
  • Add additional material in 1 mm increments and polymerize.
adding composit material
  • Finish the restoration with abrasive disks.
  • Run the disks from the resin to the metal at the margins so as not to discolor the resin with metal particles.

While more aesthetic than a conventional stainless steel crown, a shortcoming of an open-faced, stainless steel crown is the bleeding of the metal color from the lingual and interproximal surfaces through the composite resulting in a grayish tinge to the facing.7