Safari 7

Prosthodontics Overview

• Course Information: Prosthodontics 1 - Lecture 2nd Semester I S.Y. 2024-2025

• Module Topic: Full Veneer Crown

Materials Used in Dental Crowns

• Types of Materials:

  • Porcelain fused to metal

  • Ceramic

  • Gold alloy

  • Base metal alloy

  • Zirconia

Types of Full Veneer Crowns

1. Complete Cast Crown

• Introduction:

  • Recommended for restorations of badly damaged posterior teeth.

  • Longevity is superior to other fixed restorations.

  • Covers all axial walls and occlusal surface of the tooth.

• Definition:

  • A restoration that covers all the coronal surfaces.

  • Replaces lost tooth structure, providing structural support.

  • Used when less extensive designs are inadequate for restoration.

  • Not recommended where there is uncontrolled caries.

2. Full Cast Preparation Steps

1. Guiding Grooves for Occlusal Reduction:

   • Use a round-end tapered diamond.

   • Position grooves at central and developmental grooves; focus on cusp tips.

   • Depth and Angulation:

     • Non-functional cusp: 0.8mm reduction.

     • Functional cusp: 1.3mm, angled slightly flatter.

   • Ensure anatomical configuration to minimize tooth structure loss.

2. Occlusal Reduction:

   • Remove remaining tooth structure between grooves, preserving morphology.

   • Use round-end tapered diamond; reduce in two halves.

     • Functional cusps: 1.5mm; Non-functional: 1mm.

3. Functional Cusp Bevel:

   • Bevel on functional cusp is crucial for occlusal reduction.

   • Use round-end tapered diamond; failure to bevel can lead to poor casting.

4. Verifying Reduction/Clearance:

   • Use utility wax to check for thickness, then evaluate in patient’s mouth.

5. Alignment Grooves for Axial Reduction:

   • Place grooves in each buccal and lingual wall for parallelism.

   • Use tapered diamond; ensure the shank is parallel to the line of preparation.

6. Facial & Lingual Walls:

   • Reduction with tapered torpedo diamond while maintaining a cervical chamfer.

   • Width of chamfer: 0.5mm.

7. Proximal Reduction:

   • First, use a thinner tapered diamond; maintain enamel lip.

   • Place metal matrix to protect adjacent teeth.

8. Finishing Functions:

   • Use fine-grit diamond bur for a smooth finish.

9. Additional Retentive Features:

   • Use tapered carbide bur to create grooves or boxes to enhance retention.

10. Evaluation:

    • Detect common errors and correct before making interim restoration.

3. All Ceramic Crowns (Jacket Crown)

• Introduction:

  • Aesthetically pleasing; no underlying metal.

  • Better resemblance to natural tooth structure.

• Indications:

  • High esthetic requirements.

  • Proximal or facial caries no longer restorable with composites.

  • Intact incisal edge and favorable occlusal load distribution.

• Contraindications:

  • Situations requiring superior strength, unstable crown length.

  • Young patients with large vital pulp or those with high fracture risk.

• Advantages:

  • Excellent aesthetics and good tissue response.

• Disadvantages:

  • Lower strength, brittle, and wear on opposing teeth.

Preparation for Porcelain Jacket Crown

• Initial Steps:

  • Alignment with incisal portion of facial surface using flat-end tapered diamond.

  • Create depth orientation grooves, reducing structure through proximal surfaces.

Metal-Ceramic Crown (PFM Crown)

• Introduction:

  • Full metal crown with ceramic covering.

• Indications:

  • Complete coverage needed; used as retainer for fixed partial dentures.

• Contraindications:

  • Large pulp exposure risk, poor oral hygiene patients.

• Advantages & Disadvantages:

  • High strength but can fracture; esthetics inferior to jacket crowns.

Production of Metal Copings

• A. Casting of metals/alloys (e.g., CP Ti, nickel-chromium alloy)

• B. Other methods: burnishing metal foils, electro-deposition, CAD-CAM processing.

Partial Veneer Crowns

• Introduction:

  • Extracoronal restorations covering part of the clinical crown.

• Indications:

  • Sound tooth structure and average crown length.

• Contraindications:

  • High caries rate, short clinical crowns, non-vital teeth.

• Advantages:

  • Conserves tooth structure and easier access for finishing.

• Disadvantages:

  • Less retention than complete crowns; skillful preparation is crucial.