All Ceramic Restorations in Fixed Prosthodontics

Flashcards covering key concepts from the lecture on all-ceramic restorations and their applications in fixed prosthodontics.

Define Fixed Dental Prosthesis

A prosthesis that is securely fixed to a natural tooth or teeth, or to one or more dental implants; it cannot be removed by the patient.

Define Partial-Coverage Restoration

An artificial replacement that restores missing tooth structure by surrounding part of the remaining structure with materials such as cast metal alloy, ceramics, or resin.

Indications for Complete Ceramic Crown

1. extensive loss of tooth structure

2. existing complete crown

3. major morphological modification

4. significant shade change

All-Ceramic Restorations Advantages

1. superior esthetics

2. good tissue response

3. digital workflow capability

4. higher mechanical strength

All-Ceramic Restorations Disadvantages

1. Critical preparation design

2. Strict bonding protocols

3. Opposing tooth wear

4. Brittleness

Indications for All-Ceramic Restorations

1. High esthetic requirements

2. Favorable distribution of occlusal load

Contraindications for All-Ceramic Restorations

1. More conservative restorations applicable

2. Unfavorable distribution of occlusal load

Flexural Strength

The material's ability to withstand bending forces without breaking or deforming.

Dental Ceramics

Materials that typically have strong, directional, ionic bonds between metals and oxygen, providing strength but limited tolerance to distortion.

Dental Ceramics composition

1. Glassy phase

2. 1+ Crystalline phase

Consequence of Increasing Crystalline phase amount

1. Crystalline reinforcement

2. Increase resistance of crack propagation

3. Decrease translucency

Feldspathic ceramic porcelain composition

1. Glassy phase

2. Embedded leucite crystals

Advantages of Feldspathic porcelain

1. High translucency

2. Highly esthetic results

3. Technique sensitivity

4. Low flexural strength

Uses for Feldspathic porcelain

1. Ceramic veneers

2. Metal-ceramic restorations

Glass-dominated ceramics

Ceramics with more crystalline phase than glass; crystals are usually fluoroapatite or leucite

Leucite-Reinforced Glass Properties

1. Sufficient translucency

2. Moderate esthetic results

3. Less technique sensitivity

4. Higher flexural strength (85-112 MPa)

What are crystalline-dominated ceramics and what are they made of?

Alumina or zirconia, doped with ions (magnesium or yttrium);

they are ~70% crystalline, with crystals such as

• spinel

• zirconia

• alumina

• or lithium disilicate

Phases of Zirconia

1. Monoclinic (m)

2. Tetragonal (t)

3. Cubic ©

This phase does not possess exceptional mechanial properties

Monoclinic

Tetragonal zirconia phase

Superior mechanical properties, unstable at room temp

What is added to stable zirconia t-phase at room temp?

Dopants to enhance strength and partially stabilized at room temperature

Lithium Disilicate

A type of glass-ceramic used in dental restorations, known for its translucency and flexural strength.

Zirconia

A high-strength ceramic material used in dentistry, available in multiple phases including monoclinic, tetragonal, and cubic.

Monolithic Ceramics

Ceramic restorations made from a single material without layering, often demonstrating high strength and esthetic qualities.

CAD/CAM Technology

Computer-Aided Design and Computer-Aided Manufacturing used in creating precise dental restorations.

Lithium Disilicate properties

1. More translucent

2. Press & CAD/CAM

3. Laminated / monolithic

4. Flexural strength 215-400 MPA

Zirconia properties

1. More reflective

2. CAD/CAM

3. Laminated / monolithic

4. Flexural strength 900-1200 MPa

Why are monolithic ceramics favorable for crowns and FPDs?

High survival and low complication rates; although monolithic zirconia is stronger than lithium disilicate in lab conditions, clinical survival and complications are similar.

Advantages of supragingival finish lines (5)

1. Preserve tooth structure

2. Reduce soft tissue trauma

3. Improve impression accuracy

4. Enhance bonding strength

5. Maintain periodontal health

Disadvantages of supragingival finish lines (1)

Potential visibility of tooth-restoration interface

Advantages of subgingival finish lines

1. Restore deep caries, cervical erosion, or existing subgingival restorations

2. Enhance retention/resistance form

3. Conceal tooth-restoration interface

Disadvantages of subgingival finish lines (5)

1. Compromise tooth structure

2. Increase soft tissue trauma

3. Challenge impression efficacy

4. Complicated bonding procedures

5. Difficult to maintain periodontal health

What is the cavosurface angle for rounded shoulder finishing lines?

90 degrees