Tooth preparation for Metal ceramic crowns.

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
areasMetal 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.
•DurabilityMore ( 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 appearanceCharacterization
•Good retentionAll axial walls are included.
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Reinforcement and support to brittle ceramic.
stainsIntrinsic
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