In our practice at Noradent, it is often necessary to restore severely damaged teeth by placing full coverage restorations. These are called dental crowns. They are used to fully coat all tooth surfaces like tooth-shaped caps (the so-called “artificial teeth” by patients).
Types of materials used for dental crowns:
- Zirconium dioxide – zirconia
- Lithium disilicate glass-ceramic – pressed ceramic
- Ceramic layered zirconia
- Metal ceramic, metal, etc.
Zirconium dioxide is known as “white metal.” It is a non-metallic material with exceptionally high and unique mechanical properties such as tensile strength, high hardness, etc. Zirconia crowns, also called “full contour” are made using CAD/CAM technology.
Advantages of zirconia crowns:
- High hardness
- Maximum strength
- Excellent biocompatibility with oral tissues
- Minimal risk of allergic reactions
- High fracture toughness
- Ability to create very thin crowns of zirconium dioxide with minimal invasive preparation of hard dental tissues (enamel/dentin)
- Zirconia material has high abrasion resistance
- Zirconia structure has smooth surfaces that prevent dental plaque retention
Disadvantages of zirconia structures:
- Insufficient aesthetic quality – more opaque (not transparent) than natural teeth
- Suitable for restoring teeth in posterior (back) regions like molars and premolars
- Polishing in the dental office using rubber and pastes is difficult and time-consuming
The Noradent team chooses which material will be suitable for crown based on the clinical case. An examination is conducted, and if necessary, X-rays are taken, followed by the development of a dental treatment plan based on a comprehensive patient assessment. The material is selected based on the area where the tooth needs restoration. Zirconia crowns are often fabricated for posterior (back) teeth that are not so visible when smiling.
Zirconia monolithic crowns for front teeth (anterior) are not recommended due to the inability to achieve a high aesthetic result.
Both single crowns and bridges (prosthetic crown and bridge constructions) can be made from zirconium dioxide. This zirconia material is nearly unbreakable because of its high physical properties.
Reasons for fabricating single zirconia crowns and bridges:
- Severe tooth destruction with multiple missing walls
- Discoloration after using certain types of pastes during root canal filling, etc.
- Tooth injury – fractures, etc.
- High degree of tooth wear
- Missing teeth – placement of bridges or crowns over implants
The specialists at Noradent dental studio require several visits to place a zirconia crown.
1. In the first visit, the respective tooth is prepared and shaped conservatively. A temporary crown is made using either a direct method in the dental office or an indirect method in the dental laboratory.
2. After a few days, final impressions are taken and sent to the dental technician to fabricate the zirconia crown. The colour is determined to match the adjacent structures.
3. A trial is conducted, and if necessary, adjustments are made. Throughout this time, the patient wears a temporary crown made of PMMA (polymethyl methacrylate provisional crown).
4. In the final visit, the patient approves the permanent zirconia crown, which is then sealed.
In the dental laboratory, zirconia crowns are polished and glazed exceptionally well by technitians. This prevents plaque retention and promotes good personal oral hygiene.
With monolithic zirconia crowns, which are made entirely of zirconium dioxide without a layer of ceramic (unlike metal-ceramic ones), there is no risk of chipping (pieces breaking off).
In our practice at Noradent, we frequently use this type of zirconia crowns, considering zirconium dioxide to be a material that combines maximum strength and optimal aesthetics.