Comparison of Dental Materials: Zirconia, PFM, Lithium Disilicate, and Feldspathic Porcelain

An In-Depth Analysis of Common Dental Restoration Materials

Key Takeaways

Zirconia offers the highest strength and durability, making it ideal for long-span and high-stress restorations.
Lithium disilicate provides superior esthetics with moderate strength, suitable for anterior restorations and veneers.
PFM combines strength with good esthetic properties, but may have limitations due to metal substructures.

Introduction

In the realm of dental restorations, selecting the appropriate material is pivotal for ensuring longevity, functionality, and esthetic appeal. The four primary materials utilized in contemporary dental practice are zirconia, porcelain-fused-to-metal (PFM), lithium disilicate, and feldspathic porcelain. Each of these materials exhibits distinct properties that influence their indications, contraindications, survival rates, and overall clinical performance. This comprehensive comparison delves into the characteristics of each material to aid dental professionals in making informed decisions tailored to individual patient needs.

Zirconia

Indications

Posterior crowns and bridges due to high strength and durability.
Full-arch restorations and implant-supported prostheses.
Long-span restorations requiring robust support.
Patients with bruxism or high occlusal forces.
Situations requiring masking of underlying tooth structure.

Contraindications

Anterior restorations where high translucency and esthetics are paramount (unless using translucent zirconia).
Cases requiring extreme esthetics without layering porcelain.
Patients sensitive to metal components, although zirconia is generally biocompatible.

Survival Rate

10-year survival rate ranges between 95-98% for single crowns and 90-95% for bridges, indicating high long-term reliability.
Monolithic zirconia restorations exhibit lower fracture rates compared to layered zirconia due to reduced chipping risks.

Advantages

Exceptional fracture toughness and high flexural strength, with flexural strength around 900-1200 MPa.
Biocompatible with minimal bacterial adhesion, reducing the risk of peri-implantitis.
High resistance to wear and abrasion, ensuring prolonged functional lifespan.
Suitable for long-span restorations due to its durability.
Can be used as monolithic restorations, minimizing the risk of veneer chipping.
Improved esthetic properties with newer translucent zirconia formulations.

Disadvantages

Historically, zirconia has lower translucency compared to other ceramics, though advancements have mitigated this to an extent.
Hardness greater than natural enamel, potentially leading to wear on opposing dentition if not properly polished.
Layered zirconia restorations can be prone to veneer chipping and delamination.
Requires precise milling and sintering, necessitating advanced laboratory techniques.
Shade matching can be challenging, especially in anterior regions requiring high esthetic standards.

Other Factors

Monolithic zirconia reduces the complexity of the restoration process, as it eliminates the need for a veneering porcelain layer.
Advancements in CAD/CAM technology have enhanced the precision and efficiency of zirconia restorations.
Esthetic improvements in zirconia make it a more viable option for moderately esthetic zones.
Cost considerations may be higher compared to some other materials due to the advanced manufacturing processes involved.

Porcelain-Fused-to-Metal (PFM)

Indications

Both anterior and posterior crowns and bridges, offering a balance between strength and esthetics.
Long-span bridges requiring durable and supportive materials.
Patients with moderate to high occlusal forces benefiting from the strength of the metal substructure.
Precision attachments and cases where a robust framework is essential.

Contraindications

Patients with metal allergies or sensitivities, particularly to alloys like nickel.
Cases demanding high translucency and esthetics, such as in highly esthetic anterior restorations where metal margins may be visible.
Patients seeking fully metal-free restorations due to personal or medical preferences.

Survival Rate

10-year survival rate ranges from 90-95% for single crowns and 85-90% for bridges, reflecting longstanding clinical success.
PFM restorations are often considered a "gold standard" due to their durability and reliability over multiple decades.

Advantages

Proven clinical success with over 60 years of use in dental restorations.
High strength and durability provided by the metal substructure, suitable for stress-bearing areas.
Good esthetics achieved through the layering of porcelain over the metal framework.
Versatile applications, including long-span bridges and areas experiencing high occlusal forces.
Can be placed in regions requiring robust support and precision attachments.

Disadvantages

Metal substructure can lead to grayish or dark margins over time, affecting esthetics, especially in the anterior region.
Porcelain chipping and delamination from the metal framework is a common complication.
Heavier and bulkier compared to all-ceramic alternatives, potentially impacting patient comfort.
Risk of metal allergies or sensitivities in susceptible individuals.
Cost considerations, as PFMs may be more expensive than some all-ceramic options yet less so than the strongest ceramics like zirconia.

Other Factors

Requires more significant tooth reduction due to the thickness of the metal and porcelain layers involved.
Cost-effective compared to some all-ceramic restorative materials, making it a popular choice for many dental practices.
Laboratory skills significantly influence the esthetic outcome; skilled technicians are essential for optimal results.
Advancements in zirconia materials offering enhanced esthetic performance may be leading to a gradual decline in PFM preferences for certain applications.

Lithium Disilicate

Indications

Anterior crowns and veneers due to their excellent esthetic properties, such as high translucency and color variegation.
Posterior single crowns in patients without bruxism or high occlusal forces.
Inlays, onlays, and partial crowns where moderate strength and superior esthetics are required.
Minimally invasive restorations, benefiting from the material's ability to be milled or pressed for precise customization.
Clinically appropriate for single-unit restorations requiring both esthetics and sufficient strength.

Contraindications

Long-span bridges or multi-unit restorations due to its limited flexural strength (360-500 MPa) compared to zirconia and PFM.
Patients with severe bruxism or parafunctional habits that exert excessive occlusal forces, potentially compromising the restoration's integrity.
High-stress areas within the mouth where higher-strength materials like zirconia or PFM would be more suitable to prevent fracture.

Survival Rate

10-year survival rate of 96-98% for single crowns, demonstrating their long-term reliability and performance.
Veneers and inlays/onlays exhibit a survival rate of approximately 93-96% over 10 years, reflecting good durability.

Advantages

Superior esthetics achieved through high translucency and the availability of multiple shades, closely mimicking natural tooth appearance.
Moderate flexural strength (~400 MPa) suitable for single-unit restorations in both anterior and selected posterior regions.
Monolithic restorations reduce the risk of porcelain chipping, enhancing longevity.
Excellent bonding capabilities, providing superior retention and marginal seal when properly adhered to tooth structure.
Less wear on opposing dentition compared to zirconia, ensuring preservation of natural enamel.
Versatile application allowing for both milling and pressing techniques, offering customization in laboratory settings.

Disadvantages

Lower strength compared to zirconia, limiting its suitability for long-span bridges or high-stress applications.
Technique-sensitive during prosthesis fabrication, as precise bonding, etching, and silanization processes are critical for success.
Higher cost compared to PFM and some other all-ceramic materials, potentially making it less accessible for some patients.
Requires careful handling to prevent fractures, as the material, though strong, is more prone to breakage under excessive force than zirconia.

Other Factors

Ideal for minimally invasive preparations, potentially preserving more of the natural tooth structure due to its esthetic properties.
Enhancements in CAD/CAM technology have facilitated the precise milling and customization of lithium disilicate restorations.
Can be used in combination with other materials to optimize both esthetic and functional outcomes in complex cases.
Patient-specific factors, such as aesthetic demands and functional requirements, play a significant role in material selection.

Feldspathic Porcelain

Indications

Veneers for highly esthetic anterior restorations, providing a natural appearance and translucency.
Inlays and onlays for minimally invasive restorations in areas with low occlusal forces.
Low-stress crowns where superlative esthetics are a priority over strength.
Areas requiring excellent optical properties to achieve lifelike results.

Contraindications

Posterior restorations with high occlusal forces due to the material's low flexural strength (~100 MPa).
Patients with bruxism or parafunctional habits that may increase the risk of fracture and chipping.
High-stress environments within the oral cavity where greater strength materials like zirconia or PFM would be more suitable.

Survival Rate

10-year survival rate of 85-90% for veneers and single crowns, indicating moderate long-term performance.
Lower survival rates in high-stress applications due to inherent material brittleness.

Advantages

Outstanding esthetics, with superior translucency and a natural appearance that closely resembles natural enamel.
Minimal tooth reduction is required, promoting conservation of the natural tooth structure and facilitating inexpensive, minimally invasive preparations.
Excellent wear resistance and biocompatibility, ensuring long-term harmony with surrounding oral tissues.
Centrally used in anterior esthetic cases due to its superior optical qualities and thinness.
Can be layered to achieve lifelike results, enhancing the esthetic outcome of restorations.

Disadvantages

Very low flexural strength (~100 MPa), making it unsuitable for high-stress restorations such as posterior crowns.
Prone to fracture and chipping, especially in areas experiencing significant occlusal forces.
Technique-sensitive, requiring highly skilled laboratory techniques to achieve optimal esthetic and structural outcomes.
Restricted indications limit the material's versatility in clinical applications.

Other Factors

Often used in combination with other materials, such as zirconia or metal substructures, to balance esthetic and structural needs in complex restorations.
Highly dependent on the skill and precision of the dental technician to fabricate restorations that meet both esthetic and functional requirements.
Best suited for minimally invasive restorations, promoting tooth preservation and reducing the need for extensive tooth reduction.

Comparison Table

Material	Strength	Esthetics	Survival Rate	Primary Indications	Primary Contraindications
Zirconia	Highest (900-1200 MPa)	Moderate to High (improved with translucent formulations)	95-98% (10 years for single crowns)	Posterior crowns, implant-supported restorations, long-span restorations	Extreme esthetic anterior work without layering porcelain, highly esthetic anterior where translucency is critical
Porcelain-Fused-to-Metal (PFM)	High (depends on alloy used)	Moderate (opaque framework may affect margins)	90-95% (10 years for single crowns), 85-90% for bridges	Long-span bridges, posterior crowns requiring strength, areas with high occlusal forces	Patients with metal allergies, cases requiring high translucency and esthetics
Lithium Disilicate	Moderate (360-500 MPa)	Excellent (high translucency and natural appearance)	96-98% for single crowns over 10 years	Anterior crowns, veneers, inlays/onlays, single posterior crowns	Long-span bridges, high-stress areas, severe bruxism
Feldspathic Porcelain	Low (~100-120 MPa)	Excellent (superior translucency and natural appearance)	85-90% for veneers and single crowns over 10 years	Veneers, anterior restorations, low-stress areas	High-stress restorations, posterior areas, patients with bruxism

Conclusion

Choosing the appropriate dental restorative material is a multifaceted decision that hinges on various factors, including the specific clinical situation, esthetic demands, functional requirements, and patient preferences. Zirconia stands out for its exceptional strength and durability, making it the material of choice for high-stress areas and long-span restorations. Its improved esthetic properties, particularly with newer translucent formulations, expand its applicability, including select anterior restorations.

Porcelain-fused-to-metal (PFM) restorations remain a reliable option, offering a balance between strength and esthetics with a long history of clinical success. However, their potential for metal-induced complications and limitations in esthetic zones necessitate careful consideration of patient-specific factors.

Lithium disilicate provides an outstanding esthetic solution with adequate strength for single-unit restorations and selected multi-unit scenarios. Its versatility in both milling and pressing techniques, coupled with excellent bonding capabilities, makes it a preferred choice for anterior crowns and veneers where esthetic outcome is paramount.

Feldspathic porcelain excels in achieving superior esthetics, especially in minimally invasive anterior restorations. Nevertheless, its lower flexural strength and susceptibility to fracture in high-stress environments limit its use to specific indications.

Ultimately, meticulous case assessment and a thorough understanding of each material's properties guide optimal restorative outcomes, ensuring durability, functionality, and esthetic satisfaction for patients.

Comparison of Dental Materials: Zirconia, PFM, Lithium Disilicate, and Feldspathic Porcelain

An In-Depth Analysis of Common Dental Restoration Materials

Key Takeaways

Introduction

Zirconia

Indications

Contraindications

Survival Rate

Advantages

Disadvantages

Other Factors

Porcelain-Fused-to-Metal (PFM)

Indications

Contraindications

Survival Rate

Advantages

Disadvantages

Other Factors

Lithium Disilicate

Indications

Contraindications

Survival Rate

Advantages

Disadvantages

Other Factors

Feldspathic Porcelain

Indications

Contraindications

Survival Rate

Advantages

Disadvantages

Other Factors

Comparison Table

Conclusion

References