SITI FATIMAH BINTI MOHD KAMAL2ND YEAR DENTISTRY

METAL-CERAMIC RESTORATIONAlso called porcelain fused to metal restoration (PFM).It consists of a ceramic layer bonded to a thin cast metal coping that fits over the tooth preparation. Metal-ceramic restoration combines the strength and accurate fit of a cast restoration with the cosmetic effect of a ceramic crown.The metal substructure made Metal-ceramic restoration have greater strength than restorations made of ceramic alone.

Metal-ceramic restoration can be used in a wide variety including the replacement of missing teeth with fixed-partial denture.

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PREPARATION STEP

The tooth preparation is also combine of deep reduction facially and shallower reduction lingually.There may be a wing on each proximal surface where the deep reduction ends and the shallower proximal reduction begins.A uniform reduction of approximately 1.2mm is needed over the facial surface of anterior metal ceramic crown.

ARMAMENTARIUM

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1. Lab knife with no:25 blade.2.Silicone putty.3. Round – End tapered diamond.4. Small wheel diamond5. Long needle diamond.6. Radial fissure bur (rounded shoulder)7. Modified binangle chisel.

ANTERIOR METAL-CERAMIC CROWN PREPARATION

PROPERTIES :

FACIAL MARGIN# Deep Chamfer

# Shoulder with bevel# Shoulder# Radial shoulder

STEP NO. 1

Placement of depth orientation grooves – (1.2mm)The Labial grooves are cut in two sets. 1. One set parallel with the gingival half

of labial surface. 2. One set parallel with the incisal half of labial surface.

STEP NO. 2Incisal reduction – (2mm) using round-end tapered diamond.

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STEP NO. 3Labial reduction (incisal half) using round-end tapered diamond.

STEP NO. 4Labial reduction (gingival half) using round-end tapered diamond.

STEP NO. 5 Lingual reduction (0.7-1mm) using small wheel diamond.

STEP NO. 6Initial proximal reduction using long needle diamond.

STEP NO. 7Lingual axial reduction using round-end tapered diamond.

STEP NO. 8Smoothening the sharp angles.

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POSTERIOR METAL-CERAMIC RESTORATION

STEP NO. 1

Occlusal reduction followed by functional

cusp bevel.STEP NO. 2

Depth orientation grooves.

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STEP NO. 3

Facial reduction-occlusal half.

STEP NO. 4

Facial reduction gingival half.

STEP NO. 5

Proximal axial reduction.

STEP NO. 6

Lingual axial reduction.

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STEP NO. 7Axial finishing.

STEP NO. 8Gingival bevel.

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Indications of Metal Ceramic:

The metal ceramic crown is indicated on teeth that require complete coverage, where

significant esthetic demands are the placed on the dentist.

Ex:-anterior teeth.

Extensive tooth destruction as a result of caries, trauma of existing previous restorations

that precludes the use of more conservative restoration.

For superior retention & strength.

An endodontically treated teeth in conjunction with a suitable structure.

Ex:-post & core

If all ceramic crown is contraindicated

Contraindications of Metal Ceramic and Complete Ceramic Crowns: Contraindications for the metal-ceramic crown, as for all fixed restoration, include patients

with active caries of untreated periodontal disease.

In young patients with large pulp chambers.

Intact buccal wall.

When more conservative retainer is technically feasible.

Advantages: The metal-ceramic restoration combines to a large degree the strength of cast metal with the

esthetics of an all ceramic crown.

Retentive qualities are excellent because all axial walls are included in the preparation.

Natural appearance can be closely matched by good technique and if desired through

characterization of the restoration with internally /externally applied stains.

In addition, the required preparation often is much less demanding than for partial-coverage

retainers.

Disadvantages: Removal of substantial tooth structure.

Subject to fracture because porcelain is brittle.

Difficult to obtain accurate occlusion is glazed porcelain.

Expensive.

Inferior esthetics compared to all ceramic crown.

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