Quartz 4

F1 FullMetalCrowns

4 min read

Complete Cast Crown Preparation1

Full Gold Crown Overview23

Note

A complete cast crown, particularly a full gold crown (FGC), is a durable and conservative indirect restoration. While its aesthetics are a significant drawback in modern dentistry, its mechanical properties and longevity make it an excellent choice in specific clinical situations.

Advantages

  • Longevity
    • Full metal crowns have one of the greatest longevities of all dental restorations, demonstrating a lower annual failure rate compared to other indirect restorations (like ceramics) and direct restorations (like composites and amalgams).
  • Resistance
  • Conservative
    • They require the least amount of tooth reduction. Gold and other metals are not brittle like porcelain; they wear down slowly over time rather than chipping. This allows for a thinner restoration, preserving more natural tooth structure.
  • Adjustability
  • Ideal for Short Clinical Crowns
    • Because less occlusal reduction is needed (1.0–1.5 mm for gold vs. ~2.0 mm for ceramics), a greater amount of vertical wall height is preserved. This is crucial for achieving adequate retention and resistance form on teeth that are already clinically short, especially in the posterior region.

Disadvantages

  • Aesthetics
    • The primary disadvantage is the metallic appearance. Many patients prefer tooth-colored restorations and do not want visible gold or metal in their mouths.

Common Applications

  • Maxillary molar
  • Mandibular molar and premolar
  • Restoration of posterior teeth, particularly those with short clinical crowns where maximizing retention is critical.

Indications4

  • Short clinical crowns
  • Maximum retention and resistance are needed
  • High displacement forces
  • Situations requiring high strength and durability.
  • Cases with limited occlusal clearance where more conservative reduction is necessary.
  • Patients who are heavy bruxers, as gold wears at a rate similar to natural tooth enamel and is less likely to fracture or wear the opposing dentition.

Contraindications

  • High esthetic need
    • Teeth within the

Preparation Criteria56

Note

The guidelines for a full metal crown preparation are designed to be conservative while providing adequate space for the material and ensuring the restoration’s longevity.

  • Occlusal
    • Non-functional cusp: 1.0 mm
      • This includes the buccal cusps of maxillary teeth and the lingual cusps of mandibular teeth.
    • Functional cusp: 1.5 mm
      • This includes the palatal cusps of maxillary teeth and the buccal cusps of mandibular teeth. These areas bear the most occlusal force and require greater material thickness.
  • Axial: 1.0 mm
    • Two planes of reduction are necessary on the buccal and lingual surfaces to accommodate the tooth's natural contour while maintaining an ideal path of insertion.
  • Margin: chamfer > 0.5 mm
    • A chamfer margin is the standard for all-metal crowns. It is a conservative margin that provides sufficient bulk for the metal without requiring the aggressive reduction of a shoulder margin used for ceramics.

Preparation Armamentarium7

Note

The same basic set of instruments is used for most crown preparations, with variations in bur choice depending on the material and desired reduction.

Diamond burs

  • Major reduction
  • Different grits
    • Tapered and Straight Burs: Tapered burs are commonly used to establish the correct taper for the preparation. Straight burs can be helpful for clinicians who tend to over-taper their preparations.
    • Coarse-Grit Burs (Green or Blue Bands): Used for initial gross reduction of tooth structure.
    • Fine-Grit Burs (Red or Yellow Bands): Used for finishing and smoothing the preparation before taking an impression.
    • Shaped Burs (Round, Football, Tapered Round): Used for occlusal reduction and for rounding sharp line angles.

Carbide burs

  • Refinement
  • Different roughness
    • Tungsten carbide burs are available but are generally used less frequently for this procedure.

Other Instruments & Materials

  • Polishing Systems: Sof-Lex discs or Enhance burs for final polishing.
  • Impression Materials: Retraction cord, putty base and catalyst for silicone indices.
  • Temporary Crown Materials.

Preparation Steps8

challenging cases.==

Footnotes

  1. Original PDF page 1: F1 Metal Crowns, p.1 ↩

  2. Original PDF page 2: F1 Metal Crowns, p.2 ↩

  3. Original PDF page 3: F1 Metal Crowns, p.3 ↩

  4. Original PDF page 4: F1 Metal Crowns, p.4 ↩

  5. Original PDF page 5: F1 Metal Crowns, p.5 ↩

  6. Original PDF page 6: F1 Metal Crowns, p.6 ↩

  7. Original PDF page 7: F1 Metal Crowns, p.7 ↩

  8. Original PDF page 8: F1 Metal Crowns, p.8 ↩

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