Clinicians who wish to provide patients with excellent dental restorations often choose zirconia crowns. These crowns are chosen over conventional PFMs (Porcelain Fused to Metal) or full-gold crowns due to their superior strength, durability, and excellent aesthetics. Zirconia crowns require shoulder or chamfer margins for best results. They may be fabricated from solid full-contour zirconia or from layered zirconia and can be either screw-retained or cemented.
Solid or Layered Zirconia?
Solid zirconia or “monolithic zirconia” has a natural translucency and opalescence but due this trait, it is generally recommended for posterior crowns. This material is also particularly suitable for people who may grind their teeth because of its high strength. Only minimal clearance is required and there is low wear on opposing teeth. Solid zirconia is also very effective for masking highly discolored dental preps, specifically those that have darkened due to previous dental treatments, such as a post and core or a restored dental implant.
Layered zirconia is more translucent and opalescent, but unlike solid zirconia, it is especially suitable for anterior crowns. Although generally used for anterior crowns, layered zirconia may also be used for posterior crowns if there is sufficient clearance from other teeth. When done skillfully, the very best aesthetic results can be achieved. Both solid and layered zirconia crowns have a strength and consistency that is comparable with traditional PFM restorations, yet they provide far superior aesthetics.
The product is 100% metal-free, a feature that prevents gingival darkening and removes the possibility of exposing metallic margins if gum recession begins. They are naturally esthetic, transmit the color of adjacent teeth, and can be matched to any shade.
Advantages of Choosing Zirconia Crowns
- Zirconia crowns are highly biocompatible, as the smooth surface helps to reduce plaque accumulation. Solid zirconia crowns are extremely strong. Even though the porcelain used for layering does not have the strength of solid zirconia, they are designed to bond with the zirconium substructure and chipping and fracturing are extremely rare. The material also promotes a healthy tissue response.
- Zirconia is suitable for patients with metal allergies or who would prefer to have metal-free restorations.
- Zirconia is metal-free, which prevents darkening around the gingival area. This eliminates the possibility of metal margins becoming exposed due to gum recession.
- The translucent nature of this material can transmit the color of adjacent teeth and it is manufactured in a wide variety of shades, making it easy to accurately match the color of the patient’s natural teeth.
- Using computer-aided design and manufacturing processes provide patients with a precise fit, reducing the chair-side time required for adjusting and cementing these restorations.
- Crowns can be conventionally cemented in place using traditional bonding techniques.
- Zirconia crowns are comfortable for patients, as they do not transmit hot and cold in the same way as conventional PFMs.
Are There Any Disadvantages of Having a Zirconia Crown?
The disadvantages of zirconia crowns are minimal. The toughness of the material has raised some concerns about friction against the tooth root and wearing down opposing teeth. Frequent checks, however, help to reduce any possible risks to opposing teeth.
Initially, only bone-white substructures could be produced for zirconia crowns, which could sometimes create problems in achieving an aesthetically-perfect appearance. Now, however, the newer generation of materials are pre-shaded and can be fabricated to provide highly aesthetic and naturally-perfect restorations with minimal tooth reduction, meeting or even exceeding patient demands for high-quality work!
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