Orthopedic dentistry using metal-free ceramics

Metal-free crowns are orthopedic structures for restoring the integrity of the coronal part of the tooth. Metal is not used in such products; modern materials are used - lithium disilicate (ceramics), zirconium dioxide, aluminum oxide. The products are durable, biocompatible, hypoallergenic, aesthetic. The service life is more than 15 years. The cost depends on the material and manufacturing technology.

E.Max ceramic crowns and veneers

Attending doctor

Strigin Vladimir Igorevich

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Types of materials

Lithium disilicate (E-max ceramic crown)

Our Center installs 2 types of ceramic crowns made of lithium disilicate (glass ceramics). They differ in indications and manufacturing technologies:

1. E-max PRESS - available in the form of pressed “tablets”. Orthopedic products are made from it under the influence of high temperatures and pressure. The strength of the material reaches 400 MPa. Suitable for making single crowns and bridges up to 3 teeth in the area of ​​the front teeth. Classic Emax PRESS monochromatic, transparent, inexpensive. A frame is made from it, onto which layers of liquid porcelain and dyes are applied to give the structure a natural shade. We use the improved E-max PRESS Multi, it is more expensive, but has a gradient of color and transparency, so it does not require porcelain coating.
2. E-max CAD - lithium disilicate blocks for the manufacture of orthopedic structures on a milling machine under software control using CAD/CAM technology. The material is more durable - up to 450 mPa, can be used for chewing units of the dentition. Robotic production eliminates the human factor, ensures an accurate fit, and eliminates adjustments. The technology makes it possible to produce thin products, so minimal grinding of teeth is required. Coloring the material with a smooth transition of shades from more saturated to transparent allows you to imitate tooth enamel.

Based on zirconium dioxide (zirconium crown)

Products based on zirconium oxide are manufactured by milling using CAD/CAM technology and have a thickness of up to 0.4 mm. The material has properties close to natural tooth enamel and has good light transmission characteristics. It gives the impression of a smooth exit of the tooth unit from the gums - at the exit in the center of the crown the color is saturated, and on the sides and at the cutting edge it is more transparent. Zirconium structures are hypoallergenic and suitable for people suffering from allergic reactions. Crowns rank first in terms of strength (up to 1200 mPa), which allows them to be installed in place of the front and chewing teeth and used in bridges of any length. Strength, biological compatibility, and high aesthetics have made zirconium dioxide a popular material. The only negative is the high cost.

Made from aluminum oxide (Procera technology)

Aluminum oxide is a translucent mineral that belongs to metal-free ceramics. Crowns made from it are less durable than zirconium, but stronger than E-max ceramics. This is enough for installation on the front and chewing teeth, making reliable bridges of different lengths. Aluminum oxide transmits light, is resistant to deformation, biocompatible, hypoallergenic. The aluminum oxide frame is manufactured using CAD/CAM technology in several stages after creating a virtual model of the product. Procera® technology from Nobel Biocare, a leader in the field of metal-free restorations in terms of aesthetic and quality characteristics, is used for production. Crowns are manufactured in a factory in the USA. The cost of products is the highest, as it includes shipping costs.

Temporary plastic crowns can also be classified as non-metal crowns. They are installed during the production of permanent teeth to protect ground teeth and to correct the bite during multiple restorations. Easy to manufacture, inexpensive. But they are not intended for long-term wear - they quickly absorb food coloring and cannot withstand constant chewing loads.

Patient reviews

I've been wearing ceramic teeth for three years now. Since I have a natural intolerance to metals, using ceramics was the only option. Before the prosthetics, I was fitted with a temporary plastic structure. It was very uncomfortable with it, as I was constantly afraid that it would crack while eating. At first, after installing a ceramic fixed prosthesis, I was also afraid to eat anything solid, but then I got used to it. And such artificial teeth cannot be distinguished from natural ones at all. I recommend to everyone!

Alexander, St. Petersburg

I installed metal-free ceramics on my front teeth 8 years ago. I'm very pleased with the result. There is no discomfort. I quickly got used to them, and you can’t tell them apart from natural ones at all. I can drink drinks and eat food at any temperature, since there is no sensitivity, but before this my teeth reacted to everything.

And although a lot of time has passed, the shade of the ceramic teeth remains the same.
My dentist promised that if I did not chew hard food (I installed dentures in front), then my teeth would last me at least 15 years. I decided for myself that as soon as this ceramic deteriorates, I will install it again. Larisa, Rostov-on-Don

Advantages and disadvantages

Advantages of metal-free structures:

• biological compatibility, hypoallergenic, metal-free;
• absence of a “gray neck” at the gums, characteristic of metal-ceramics;
• light transmittance, increasing the aesthetics of the product;
• lightness, the ability to install even on weakened teeth;
• absence of strong grinding and depulpation of the tooth;
• no sensitivity to temperature changes;
• preservation of natural shade for a long time;
• service life more than 15 years;
• tight fit to the gum.

The only negative is the high price compared to metal-ceramics, which is compensated by the listed advantages.

Indications

• Prosthetics for the first time. If the supporting teeth are strong and healthy, there is no need to depulpate them or sharpen them much. Metal-free products allow you to preserve “living” teeth.
• Replacement of outdated structures. Recently, patients are increasingly seeking to improve aesthetics and quality of life, so they turn to us to replace outdated metal-ceramic crowns.
• Allergy to metal. If metal or metal-ceramic crowns cause discomfort, metal-free crowns are the only option.
• Increased requirements for aesthetics. When a patient requires dentures that are indistinguishable from natural teeth, only a metal-free design is suitable.
• Weak supporting teeth. Metal-free products are lightweight and do not create an increased load on the teeth.

What types of prostheses are there?

A similar approach in prosthetics is used as ceramic inlays and onlays (inlays, onlays), veneers (ceramic overlays on the front part of the tooth), dental crowns and dentures. Currently, in dentistry, prosthetics using ceramic products without metal are more often used in the manufacture of fixed dentures, however, in some cases, the technique can also be used in the manufacture of removable dentures (for example, when removable dentures are fixed using microimplants).

Technologies and manufacturing stages

We give preference to crowns made in 2 ways:

1. Milling (CAD/CAM technologies). For manufacturing, the doctor scans the patient’s oral cavity (CAD), digital data is transferred to a computer, where a 3D model is recreated in a special program. The information is transmitted to milling equipment (CAM) to obtain the desired shape from the blanks. This is the main method used in our Center.
2. Pressing (used for E-max technology). High pressure and temperature are used to shape the material. The crown is made using a wax structure. It is used less frequently, but is also used at the request of the patient.

Installation

• Examination, preparation of the oral cavity

  The dentist assesses the patient's condition. If necessary, an x-ray is taken, caries is treated, non-viable units are removed, and professional cleaning is carried out.

• Tooth preparation

  Gentle grinding is carried out to the thickness of the crown, only the affected tissue is removed. Severely damaged units are strengthened with stump inlays. If necessary, temporary plastic prostheses are installed to protect against destruction while the structures are being prepared.

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• Taking impressions

  It is carried out using impression material or scanning the oral cavity with a camera.

• Making a crown

  In the laboratory, based on the models, prostheses are made by pressing or milling.

• Fitting and correction

  The prosthesis is tried on to assess its comfort and fit. If necessary, the crown is sent to the laboratory for final work to adjust the shape of the product.

• Installation

  The finished prosthesis is attached to the tooth using dental cement for fixation.

After 4-7 days, the patient is scheduled for a follow-up visit for examination and prevention of complications. The entire installation process, taking into account the preparation of the oral cavity, takes from 2 weeks to 2 months, depending on the complexity of the case.

In difficult situations, when restoration of a large number of teeth is required, as well as for doubtful patients, the design of future crowns is first selected and approved:

1. First, wax modeling of future structures is carried out on models of the patient’s jaws (Wax-up). You can see your future smile even before the start of prosthetics and make the necessary wishes for adjustments.
2. Then the resulting modeled crowns are transferred into the oral cavity in the form of temporary test products (Mock-up), without grinding the teeth. You can evaluate the functionality and check the wearing comfort before starting the main prosthetic work.

Prices

Our Center has developed prices for cases for the installation and production of metal-free crowns. The cost depends on the technology and material, includes:

• manufacturing;
• fittings;
• fixation.

Case prices for products using digital CAD/CAM technologies:

• ceramic crown E.max - 36,000-48,000 rub.
• crown made of zirconium dioxide - 38,000 rubles.
• ceramic crown on a zirconium dioxide frame - 42,000-58,000 rubles.

Lithium disilicate and zirconium dioxide crowns have fixed prices, as they are manufactured in our own laboratory using ZirkonZahn® technology. Prices for aluminum oxide crowns using Procera® technology may vary slightly depending on the ruble exchange rate.

Impressions are paid separately - 3,500 rubles. The price does not depend on the method of obtaining them (impression mass or digital scanning).

In non-standard situations, an individual crown design is required, which is paid separately:

• manual wax modeling Wax-up - RUB 1,600. for 1 unit;
• temporary plastic crowns or Mock-up - RUB 6,000. for 1 unit.

Our prices are a guarantee of high quality

Case pricing adopted in our Center may at first seem more expensive than in other clinics. But we use only high-quality materials and never purchase Chinese fakes. In addition, our system is honest - we indicate in advance all possible additional costs, do not hide anything, and do not put patients in an uncomfortable situation when drawing up the final estimate.

Levin Dmitry Valerievich

Chief physician, Ph.D.

Life time

The average service life of metal-free prostheses is 15 years. With proper care they will last longer. The timing depends on the chosen material and location in the dentition. It is of great importance how much the patient complies with the doctor’s instructions for the care of the structure and diet.

In our Center for Private Dentistry “Doctor Levin” there is a guarantee for the integrity and color of metal-free crowns made using digital technology for 25 years. Our orthopedists are confident in their work and the quality of the source material. The warranty periods are confirmed by digital passports for the products.

Caring for metal-free dentures

There is nothing complicated about caring for teeth replaced with metal-free ceramic implants. The material is characterized by low capriciousness. It is worth following standard recommendations for hygienic care. It is important to avoid using paste with large particles, as they can scratch the denture. Also, you should not chew very hard foods with their help, as the prosthetic tooth may chip. After all, the density is, of course, high, but not infinite.

With proper care of teeth replaced with dentures, the latter will last 15 or even 20 years.
A solid period that fully justifies the rather high price. Sources:

• Accurate impression - Ryakhovsky A.N., Muradov M.A.
• Dental implantology. Introductory course - Kutsevlyak V.I., Grechko N.B.
• Dental implantation (surgical aspects) - Robustova T. G.
• Dental implantation. Success criteria - Zhusev A.I., Remov A.Yu.

What is better for the front and chewing teeth?

When choosing a type of orthopedic design, the location of the tooth to be restored is taken into account:

• E-max glass ceramics are suitable for the front ones, as it allows you to achieve a natural shade of enamel;
• It is better to make dentures for molars from zirconium dioxide, which is characterized by increased strength;
• for increased demands on aesthetics, E-max Multi with gradient coloring or translucent crowns made of zirconium or aluminum oxide are suitable;
• For prostheses on implants, only zirconium is recommended for bruxism.

The recommendations described are based on the different requirements for dentures for anterior and chewing teeth. For the former, aesthetics are more important, for the latter - strength and wear resistance.

Sometimes you have to choose from all three options to decide which one is right for your specific situation. The light transmitting characteristics of materials depend on the original color and transparency of your teeth. Fittings are free, but they take time, so you need to plan prosthetics at a time when you can visit the clinic without affecting your business.

Main characteristics

Metal-free crowns include products made from:

• plastics are cheap, but fragile, quickly stain and crack, usually used for temporary prosthetics;
• ceramic composite – consist of composite materials and ceramics;
• ceramics or porcelain - inorganic material obtained by processing nitrides, metal oxides, borides, carbides at high temperatures;
• zirconium dioxide (oxide) - similar in strength to metal, and in aesthetics - similar to ceramics.

When people talk about metal-free orthopedic structures, they usually mean zirconium dioxide and ceramics. The technology for prosthetics with these materials was developed in the 80s of the 20th century, but they began to be used on a large scale in the last ten years.

Despite the high cost, metal-free crowns are very popular

Sometimes patients confuse the concepts “metal-free” and “bimetallic”. The latter term means prostheses made from an alloy of two or more metals: gold, nickel, platinum, chromium, palladium, etc.

The difference between a metal-ceramic crown and non-metal ceramics

Metal-ceramic crowns have been used in orthopedics for more than 35 years. They consist of a frame based on an alloy of chromium with cobalt or nickel and a ceramic coating. The products are durable, can withstand heavy loads, and last more than 10 years. But compared to metal-free products, metal ceramics have a number of disadvantages:

• mandatory depulpation and grinding of the tooth before installation;
• possibility of allergy to metal;
• the risk of gum subsidence and exposure of the metal base;
• chips of ceramics are possible;
• poor light transmission, which makes the prosthesis look unnatural.

In our Center, after switching to digital milling in 2000, we completely abandoned metal-ceramics in favor of metal-free products.

Alternative prosthetic options

Metal ceramics

Metal-ceramic crowns are a budget option for prosthetics. They have high strength, but lack natural aesthetics. Therefore, this method is not recommended for front teeth.

Veneers

Veneers are thin ceramic plates that cover all defects on the vestibular surface of the front teeth. The main requirements for installing veneers are complete preservation of the lingual wall of the tooth, as well as the absence of large chips.

Enamel extension

This is tooth restoration using a filling mass (photopolymer composite). The doctor applies the composite layer by layer to the defect area, illuminating each layer with a photopolymer lamp. However, this method is indicated only when the coronal part is destroyed by less than 1/2.

Comprehensive rehabilitation.
Total prosthetics with metal-free structuresDoctor: Alexey Lebedko Published by Egor Ruzov Dentistry on February 4, 2015