Zirconium crowns and bridges are so strong they can be used anywhere in the mouth. Zirconium crowns can withstand the biting pressure of the front teeth as well as back teeth grinding (bruxism). The look of zirconium crowns and bridges is so close to natural teeth that it is hard to tell the difference, and it is this quality which makes it very usable within dental work. Zirconium crowns can be fixed using traditional dental cements.
What is zirconium?
Zirconium dioxide (zirconia) is a ceramic material with exceptional strength, fracture toughness, and biocompatibility. It is metal-free, hypoallergenic, and does not corrode.
Why zirconium is superior:
-
Strength: Withstands up to 1,200 MPa of pressure (compared to 400–600 MPa for porcelain-fused-to-metal).
-
Aesthetics: Allows light to pass as a natural tooth would, unlike metal cores that block light. No dark gum line.
-
Bonding: Can be cemented with traditional or adhesive cements.
-
Biocompatibility: No metal allergy concerns; gum tissue responds well.
-
Wear on opposing teeth: Zirconium is smooth and causes less wear on opposing natural teeth compared to some other ceramics.
Zirconium vs. porcelain-fused-to-metal (PFM):
| Feature | Zirconium | PFM |
|---|---|---|
| Aesthetics | Excellent (translucent) | Good but with dark metal line |
| Strength | Very high (1,200 MPa) | Moderate (400–600 MPa) |
| Metal allergy | No | Yes (nickel, chromium, beryllium) |
| Chipping risk | Low (monolithic) | Moderate (porcelain can chip off metal) |
| Gum discoloration | None | Possible (metal show-through) |
| Light transmission | Yes | No (metal blocks light) |
The procedure:
-
Tooth preparation (shaping) under local anesthesia.
-
Digital impression or traditional mold.
-
CAD/CAM design and milling of the zirconium crown (one or two visits).
-
Try-in and color adjustment.
-
Cementation.
Statistics and research:
-
A 2018 study in the Journal of Prosthodontics reported that zirconia crowns have a 5-year survival rate of 94.5%, with fewer complications than PFM crowns.
-
Zirconium crowns have become the preferred material for posterior (back) restorations due to their strength.
-
Monolithic zirconia (full zirconia, no porcelain layering) has a chipping rate of less than 1% after 5 years, compared to 15–20% for PFM.
References:
-
Sailer, I., et al. “A systematic review of the survival and complication rates of zirconia-ceramic and metal-ceramic single crowns.” J Prosthodont, 2018.
-
Guess, P.C., et al. “Zirconia in dentistry.” Dent Mater, 2011.
-
Miyazaki, T., et al. “A review of dental CAD/CAM: current status and future perspectives.” J Oral Sci, 2009.
0 Comments