Zirconium dioxide crowns

Zirconium dioxide crowns are an alternative to porcelain and metal ceramics in dental restoration. The structure does not have a metal substructure, so it is a replica which looks the same as a real tooth.

Characteristics of the material

Zirconium dioxide made as per the Prettau technology does not contain any hazardous admixtures or metals which can cause allergies. It is highly biocompatible with tissues and mucosa. As the material has low heat conductivity, nerves are less exposed to rapid changes of temperature. A microprosthesis made of this material is noted for its natural white colour and light transparency. In terms of appearance, it is impossible to differentiate a crown from a real tooth, and its strength is a few times higher than its metal-based analogs.

The structure lasts for at least 20 years and does not get damaged or change its shade. The material allows performing dental restorations with only a little filing of neighbouring teeth. Due to the high strength of the material, it is possible to manufacture a very thin prosthesis. Zirconia is indispensable in different implant prosthetics.

Types of zirconia crowns for implants and teeth

The structures are manufactured using CAD/CAM. Zirconium dioxide pieces are milled on high-precision equipment.

Types:

• One-piece crowns are the most reliable and the strongest. Crowns are manufactured from a solid piece of zirconium dioxide and the surface is not coated with a porcelain layer. The substructure and the outer shell make a single whole, and there is no risk of chipping due to delamination of components that the surface is layered with. The strength of the structure is up to 1000 MPa, as contrasted to porcelain layered crowns with up to 100 MPa. Because of its properties, a monolithic zirconia crown will be suitable for posterior and anterior dental restorations. The Prettau technology creates semi-transparent blocks, which make a prosthetic structure look natural, so it cannot be differentiated from an original tooth.
• Traditional crowns do not have such good properties as monolithic ones. They are made of two kinds of materials: a zirconia substructure and a porcelain outer shell.

Advantages of zirconium dioxide crowns

• Using zirconia abutments is the best solution for dental implants, as they guarantee excellent adaptation of the gum to the structures, as well as good gum aesthetics around implants and a perfect positioning of microprostheses. 
• Aesthetic parameters: zirconium dioxide crowns are impossible to differentiate from natural teeth. They have the same colour rendering, translucence and texture. They do not change their shade in natural and artificial light and no dark border appears.
• Full biocompatibility: a metal-free structure does not cause allergy in a patient, no galvanism and no risk of gingivitis.
• Strength: a monolithic zirconia crown placed on an implant or a tooth may compete with a metal crown in terms of strength. There are no heterogeneous admixtures in the material.
• Secure fixation: it fits tightly to the tooth and there is no need to file down the neighbouring teeth much. The volume of dissected tissue is low, so the method is very sparing for the patient.
• Service life: more than 20 years without any deterioration of natural shade, chips or changes in density.
• Comfort: a bridgework structure is a perfect replica of natural teeth; chewing is comfortable, no pressure on the gum and no risk of falling out.
• No hypersensitivity problem: there is no metal, so the substructure is strongly resistant to cold and hot stimuli, and the patient does not feel any pain in case of a rapid change of temperature.

Price

The cost of the structure includes:

• Patient diagnostics: treatment of caries and other concomitant oral diseases, replacing old fillings.
• CAD/CAM-based manufacturing of structures in the lab of the clinic: a high-precision monolithic crown is fabricated from a single zirconia block. The crown is modeled using software; baking the crown. 
• Placing: very little tooth filing; placement on an implant or a tooth.

The prosthetic procedure takes one hour at the longest.

The benefits of zirconium dioxide in dental implants

The price of a zirocnium dioxide crown is the same whether it is for an implant or for a tooth.

Benefits:

• A super strong structure for dental implants in the upper and lower jaw in any arch segment. Combining an artificial root and a crown guarantees durability and a 100% normal chewing function.
• Zirconia abutment: using the same material for a foundation and a crown guarantees that there will not be any allergic reactions, which may occur when metal frames are used. Mucosa is not subjected to irritation, and excellent biompatibility with tissues is achieved.
• A combination of strength and reliability: an implant structure with a zirconia crown imitates a natural tooth with respect to all characteristics; reliability, colour and comfort when chewing.

Zirconia structures do not wear off with time, are not prone to chipping and the gum at the base of the tooth does not darken.

The process of implant placement and prosthetics can be single-stage or two-stage. An artificial root is inserted and an abutment is fixed. A permanent super strong crown is placed after osseointegration is complete.

Prettau technology

Zirconia blocks are made by pressing zirconia powder. After a 3D model is created, a crown or a prosthetic structure is milled on a milling machine. The substructure is sintered in an oven. Baking guarantees high strength. The resulting smooth surface ensures high wear resistance, as there is no friction with teeth, and the absence of pores prevents the risk of abrasive wear.

Zirconium dioxide manufactured as per the Prettau technology is a flexible material with high flexural strength. Prosthetics with this material ensures a long service life of crowns. The material is highly translucent, which guarantees a natural appearance of artificial teeth.

Axioma Dental Clinic has a dental lab where we manufacture microprostheses as per the Prettau technology (Zirkonzahn) using high quality zirconia with high translucency values.

Drawbacks and contraindications

These structures are high-priced, which is a drawback, but it pays off quickly because of their long service life, high strength and absence of chips, which are characteristic of monolithic products. Using traditional multilayered crowns is associated with the risk of chips of ceramics.

Contraindications:

• Deep bite.
• Gestation period.
• Inflammatory processes in the oral cavity.
• Mental disorders.
• Weakened immunity.
• Very small teeth.

Placing single crowns on front teeth and 3-unit bridges on anterior teeth is not recommended.

Proper care during rehabilitation

How to prolong the service life of artificial teeth:

• Using medium stiffness brushes and prophylaxis paste.
• Rinsing with antiseptic solutions, water and herb teas.
• Using dental floss and an oral irrigator.
• Avoiding hard food, nuts, seeds and hard candy in the diet.
• Regular visits to the dentist.
• Wearing a mouthguard in case of bruxism.

Patients get used to artificial teeth quickly, do not feel any pressure on the gums and can communicate easily.

Axioma Dental Clinic would like to offer dental restorations and full dental arch rehabilitation.

Work examples