Full Contour Zirconia Crowns
Zirconia is a natural mineral called baddeleyite. It is the oldest and most abundant mineral present in the earth’s crust. This mineral contains 80-90% zirconium oxide that is anti-allergic, translucent, completely biocompatible ( tissue friendly) and has low thermal conductivity. In the late 1980s, ceramic engineers added small amounts of calcium and later yttrium or cerium.
Zirconium is used in dentistry to make dental prosthesis. It has flexural strength and has fracture resistance beyond all other ceramic materials and offers natural beauty and an aesthetic result.
To manufacture crowns completely in zirconia, in Brighton Implant Clinic we count on CAD CAM technology. This is based on the three-dimensional scanning of the model of the patient’s mouth digitally which subsequently will be carved on a block of zirconium through a machine.
Utilizing the KaVo Everest CAD/CAM system, we can design, fabricate and place all-ceramic crowns which have demonstrated excellent fit, strength and long life span.
The advantages of using high-end material as yttrium stabilised zirconium oxide are:
- Excellent biocompatibility (tissue friendly)
- Stable flexural strength (Shrinkage between 19% and 21%).
- Excellent wear properties.
- Flexural strength 1200 MPa ( when >700 MPa is high strength).
More options available
Currently there are several systems composed of zirconia, among which highlight:
Lava TM All Ceramic System (3M ESPE).
Cercon® (Dentsply- DeguDent).
NobelProcera® Zirconia (Nobel Biocare).
In-Ceram® YZ (VITA).
IPS e.max® ZIRCAD (Ivoclar).
DC-Zircon® (DCS Dental AG).
Hint-Els® Zirconium TPZ.
Full contour zirconia crowns
A full contour zirconia crown is a crown made entirely from zirconium in a single structure, this means that there is not layer of porcelain, that is why they have the following characteristics:
- Digitally designed & milled for a precision fit, also glazed to a smooth surface to reduce plaque accumulation.
- Long term wear: The full-contour zirconia crowns and bridges avoid fracture of aesthetic porcelain on posterior crowns and bridges. The difference with a conventional crown is that these crowns are virtually unbreakable.
- Shapes and contours: These types of crowns are easily shaped and polished using conventional low-speed porcelain-polishing materials and because they are the same color all the way through, they will not exhibit the opaque show-through so often seen when adjusting the occlusal portion of a conventional crown.
- Implant restoration: It is ideal for dental implant crowns on posterior teeth because the opacity of the material hides the darkest metal abutments.
- Indicated for posterior restorations.
- Fracture resistance, because it is made without an porcelain overlay.
- Indication for restorations with lack in the space.
- Less abrasive to natural enamel than any other full-coverage ceramic system.
- Good soft-tissue response
- Less aesthetics due to the opacity of the material.
- Contraindicated for anterior restorations.
The fabrication technique of the full contour zirconia is complex and requires a very specific equipment with a large investment of time and money. There must be an adequate support and laboratory experience with the ceramics selected. From the technical point of view, it requires a masters perfect skill to process and to achieve the desired results.
There are different brands on the market that offer a wide variety of ceramic systems for total zirconia crowns. Lava™ Plus High Translucency Zirconia (3M ESPE) or Cercon® ht Full Contour Zirconia (Dentsply) could be some good systems of choice for a good aesthetic result.
Lava™ Plus High Translucency Zirconia
This formula is a new system, based on special chemistry and processing with a unique shading system. Highly esthetic, the crown can be created with a higher translucency, beauty, strength and durability.
- High strength allow a minimum of 0.5mm wall thickness in crown preparation.
- Excellent color match with 18 colors available and 8 effect Shades. This gives dentists options for near exact replicas of the patients original teeth, also the shading system enables highly esthetic all-zirconia restorations.
Cercon® ht Full Contour Zirconia (Dentsply)
This formula provides strength and esthetics ideal for full contour posterior restorations. It is designed to fully anatomic contour, is demonstrably safe for their antagonists.
- The full contour crowns milled with Cercon ht Full Contour Zirconia are more translucent than conventional zirconia and require no porcelain build-up.
- Very thin crowns can be created due to the material’s high strength.
- When opposing natural dentition this material is less abrasive than others.
- The material has translucency that exceeds porcelain-fused-to-metal and vitality similar to natural teeth.
- CAD/CAM precision fit.
- Achieves 16 custom shades keyed to Vita® Classical Shade
The introduction of new materials in dentistry, as zirconium oxide, gives us the opportunity to offer a high quality treatment with better aesthetic and lasting result.