Tooth preparation for Metal ceramic crowns.

1. Metal Ceramic Crown
Preparation

2. • Most widely used.
• Improvement in:
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Technology.
Skills.
Growing cosmetic demands.

3. • Complete coverage by metal.
• Veneer porcelain mimics
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Extention varies natural teethnatural teeth

4. Major requirement:
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More amount of tooth reduction
areas Metal veneered with ceramic.
Place for - Metal
- Porcelain
Sufficient bulk.
- Mask metal.
- Esthetics.

5. Least conservative preparation.
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7. Other problems
• Alloy’s compatibility with ceramics.
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- Physical properties.
- Adequate bond strength.
High fusing range.
Low thermal expansion.

8. Indications
• Esthetic demands.
• Durability More ( than all ceramic ).
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Marginal fit
better in all ceramics.

9. • Crown and bridges metal substrate.
• Allows placement of rests, if RPD is a part of
treatment.
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connectors

10. • Extensive tooth destruction:
• Correction of malocclusion.
• Correction of occlusal plane.
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- Caries.
- Trauma
- Existing restoration
- Endodontically treated

11. Contra indications
• Patient with active caries.
• Untreated periodontal diseases.
• Young patients with large pulp chambers.
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Risk of pulp exposure
- Porcelain laminates.
- Composite laminates.

12. • If more conservative restoration is possible.
• Long Spans.
• If facial walls are intact.
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Partial veneer is possible and favorable.

13. Advantages
• Strength Good, compared to all ceramics
• Mimic natural appearance Characterization
• Good retention All axial walls are included.
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Reinforcement and support to brittle ceramic.
stains Intrinsic
External.

14. Disadvantages
• More amount of tooth removal.
• Facial margins often Subgingivally
• Inferior esthetics compared to all ceramics.
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PDL disease
Margins supra gingivally esthetics not a problem
Indicated:

15. • Brittle fracture Poor design.
• Difficulty design / shaping and shade
matching.
• Many procedural steps.
• Expensive.
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- Casting.
- Porcelain adaptation.

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18. Preparation
• Guiding groves.
• Incisal / Occlusal reduction.
• Labial / buccal reduction.
• Axial reduction
• Final finishing.
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Proximal .
Lingual surfaces.

19. Anterior tooth preparation
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PUTTY INDEX

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24. Incisal bevel
• Palatally directed Maxillary anteriors.
• Buccaly directed Mandibular anteriors.
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25. Incisal Preparation
• Incisal edge 2mm reduction.
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Adequate thickness
Translucency

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30. • Cervical plane of reduction determines
• Incisal plane Provides space for
porcelain veneer.
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Path of withdrawal.

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39. Lingually
• Concavity
• Use foot ball shaped bur / doughnut or any
other suitable bur.
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Adequate clearance
Centric contacts

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42. Wing preparation
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44. Variants
• Wing less preparation.
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No definite Trancession from chamfer to shoulder
Shoulder gradually narrows lingually.

45. Prevention of trauma to pulp
• Adequate coolant while preparing
( copious irrigation ).
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• Intermittent strokes Preparation.

46. • Care while preparation of Subgingival
margins
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• Permanent gingival recession.

47. Finishing
• Smooth glass like / satin like finish.
• Rounden all line angles.
• No scratches marks.
• Use gingival retraction.
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49. POSTERIOR TOOTH
PREPARATION

50. POSTERIOR METAL-CERAMIC
CROWN

51. POSTERIOR METAL-CERAMIC
CROWNS
STEP NO : 1
OCCLUSAL REDUCTION
FOLLOWED BY
FUNCTIONAL CUSP
BEVEL.barell

52. POSTERIOR METAL-CERAMIC
CROWNS
STEP NO : 2
DEPTH ORIENTATION
GROOVES

53. POSTERIOR METAL-CERAMIC
CROWNS
STEP NO :3
FACIAL REDUCTION-
OCCLUSAL HALF

54. POSTERIOR METAL-CERAMIC
CROWN
STEP NO :4
FACIAL REDUCTION
GINGIVAL HALF

55. POSTERIOR METAL-CERAMIC
CROWN
STEP NO: 5
PROXIMAL
AXIAL
REDUCTION

56. POSTERIOR METAL-CERAMIC
CROWN
STEP NO :6
LINGUAL AXIAL
REDUCTION

57. POSTERIOR METAL-CERAMIC
CROWN
STEP NO : 7
AXIAL FINISHING

58. POSTERIOR METAL-CERAMIC
CROWN
STEP NO :8
GINGIVAL BEVEL

59. POSTERIOR METAL-CERAMIC
CROWN