All-porcelain labial margin for ceramometal crowns

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Prosthodontics

Background:

• Porcelain-fused-to-metal (PFM) restorations often have a metal collar at the labiogingival margin, which can compromise aesthetics.
• Patient demand for more cosmetic tooth restorations influences the adoption of techniques to conceal metal margins.

Purpose of the Study:

• To describe a modified PFM crown design that eliminates the labiogingival metal collar for improved esthetics.
• To outline the critical tooth preparation and substructure design requirements for successful all-porcelain margins.

Main Methods:

• Modifying the metal substructure by finishing the labiogingival portion to the gingival-pulpal line angle.
• Specifying metal thickness (0.3-0.5 mm) and allowing adequate space for opaque (0.2-0.3 mm) and shoulder porcelain (0.7-1.0 mm).
• Utilizing the direct lift-off technique for creating clinically acceptable all-porcelain margins.

Main Results:

• The modified design facilitates the creation of an all-porcelain margin, enhancing the esthetic outcome of PFM restorations.
• Proper preparation, including a 1.2-mm wide shoulder with specific angulation, is crucial for the success of the all-porcelain margin.
• The described technique allows for precise control over material thickness, ensuring adequate porcelain coverage.

Conclusions:

• Eliminating the labiogingival metal collar in PFM crowns can yield excellent esthetic results.
• Success is contingent upon meticulous tooth preparation and a well-designed metal substructure.
• The direct lift-off technique is a viable method for achieving high-quality all-porcelain margins in restorative dentistry.