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All‐Porcelain Labial Margin for Ceramometal Crowns
Author(s) -
Harrison Lewis,
Huffman Terry,
Goldfogel Marvin
Publication year - 1992
Publication title -
journal of esthetic and restorative dentistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.919
H-Index - 60
eISSN - 1708-8240
pISSN - 1496-4155
DOI - 10.1111/j.1708-8240.1992.tb00686.x
Subject(s) - crown (dentistry) , margin (machine learning) , gingival margin , materials science , dentistry , chamfer (geometry) , finish line , collar , orthodontics , medicine , composite material , computer science , geology , engineering , mathematics , mechanical engineering , paleontology , geometry , race (biology) , machine learning
The elimination of the labiogingival metal collar of a porcelain‐fused‐to‐metal (PFM) restoration is an attempt to achieve an improved esthetic result. In their expectation of a more cosmetic tooth restoration, patients may influence dentists to use the all‐porcelain labial margin to avoid metal showing in the final restoration. Success of this type of restoration depends upon proper tooth preparation. The all‐porcelain margin requires a 1.2‐mm wide labiogingival shoulder of approximately 70 or 90 degrees wrapping into the interproximal area. Much of the effectiveness of the restoration depends upon the design of the metal substructure. The following change is made in the design of this substructure for this modified PFM crown: the labiogingival portion of the metal is finished back to the gingival‐pulpal line angle with the metal against the axial wall being from 0.3 mm to 0.5 mm thick. This allows for 0.2 to 0.3 mm of opaque and 0.7 to 1.0 mm of shoulder porcelain. The direct liftoff technique is a useful method of achieving clinically acceptable all‐porcelain margins. Such restorations may give excellent results.