Fixed Partial Denture: Metal Coping

Porcelain fused to metal dental crowns have the following layers: enamel, body dentin, gingival dentin, opaque and metal coping.

Porcelain fused to metal dental crown



About Metal Coping

Metal Coping Properties
Metal and porcelain must have compatible melting temperature and coefficient of thermal expansion.

Characteristics
1. Metal must have a melting range above porcelain.
2. It should have resistance to sag.
3. It should possess optimum rigidity.
4. Metal must have similar thermal expansion characteristics with porcelain.
5. It should adhere to porcelain.

Metal Coping Design

Thickness of the metal
Porcelain should be ata minimum thickness that is compatible with good esthetics. The desirable thickness of porcelain is 1.00 mm.

The metal should be as hardas practical. Its design must ensure an optimum bulk to ensure strength. Metal copings should be 0.3 – 0.5 mm for noble metal coping. Base metal allloy copings should be 0.2 mm.

Intentional roughening is done on metal coping to increase mechanical bond of porcelain to metal surface.

Contacts

The porcelain metal jucntion should not be placed in the vicinity of occlusal contacts on the occlusal and lingual surface of ceramics. This done to minimize stress resulting from those contacts.

Metal-ceramic junction must not be placed close to the incisal edge.

The collar of exposed metal on the lingual must be at least 3.00 mm wide incisal-gingivally.

Proximal contacts for anteriors should be on ceramics. The metal is placed lingually to produce greater depth and transluscency proximally.

Video of Wax Sculpturing for Metal Coping

For more info about Metal Ceramic Dental Crowns, please read the articles I wrote for these informative webpages:

Metal Ceramic Crown – http://costdentures.com/fixed/porcelain-fused-to-metal-crown/
PFM Crown – http://www.dentures.com.ph/porcelain-fused-to-metal-dental-crown/

Reference
[1] Johnston J F et al: Modern practice in crown and bridge prosthodontics. WB Saunders Company

For more information on the best possible Prosthodontic Treatment for your case, please consult your Dentist. “There is no online material nor website that can substitute for professional advice.”

Written by:
Jesus Lecitona+, DMD, MScD-Prosthodontics
Email your questions about Metal Ceramic Crowns at: jes[at]lecitona.com
Dentures Cost – http://costdentures.com/

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5 Responses

  1. Dental says:

    The difficult part is to hide the metal on the gingival. It takes a good ceramist to do it right.

  2. Andrew S says:

    But as I see it just like the original tooth, nice!

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