Crowns on Implants

What is a Crown on an Implant and How Does it Look?

A crown on an implant replaces a severely damaged or missing tooth. This crown looks natural, just like a real tooth.

The shape, shade, and material of the crown are chosen before the implantation procedure. After implanting, the doctor takes an impression and develops a 3D model of the crown. This process takes into account the placement of adjacent teeth and the post, ensuring the crown fits perfectly in the tooth row.

The crown on the implant restores chewing function, prevents shifting of other teeth, doesn't exert pressure on adjacent teeth (unlike bridges), and helps prevent bone atrophy.

Advantages of a Crown on an Implant Compared to Other Options

Let's examine why a crown on an implant is the most reliable method of replacing a lost tooth compared to other restoration methods:

Bridge Prosthesis on Teeth

A bridge is a prosthesis consisting of 3-4 connected crowns. Before placing the bridge on the teeth, the dentist removes a layer of enamel from the supporting teeth (sometimes the nerve is also removed) to ensure a precise and secure connection of the artificial crowns. This method is only suitable for certain cases.

Another disadvantage of bridges is the bone loss in the area of the replaced tooth. The prosthesis replaces only the visible part of the tooth, leaving a void underneath, leading to bone loss in that area.

As a result, all the chewing pressure falls on the supporting teeth. Under high loads, they can gradually be destroyed and often are not suitable for repeated bridge prosthetics. The lifespan of a bridge is up to 10 years.

Removable Prosthesis

The prosthesis consists of a base (made of Acry-Free, nylon, or acrylic) with attached artificial crowns. Depending on the number of missing teeth, there are partial (for 1, 2, or more teeth) and complete (for the entire jaw) removable prostheses.

Partial prostheses are attached to the patient's adjacent teeth using clasps (hooks). Complete prostheses are held in place by suction and fixing creams.

The main advantage of removable prostheses is their affordable price (depending on the material and the number of teeth replaced). Other benefits include installation without surgery and fairly good aesthetics (depending on the material). The disadvantages of removable prostheses include:

• Clasps of partial prostheses may be visible when speaking (especially metallic ones);
• Discomfort during the adaptation period;
• Inefficient transfer of chewing force to the bone, leading to its atrophy;
• Falling out of the mouth (especially complete prostheses);
• Can cause pain while chewing;
• Complete prostheses may cover taste receptors;
• Irritation of the oral mucosa;
• The surface quickly becomes contaminated with microbes.

Crown on an Implant

A titanium root is implanted in the place of a lost tooth. A crown (made of ceramic, zirconium, or metal-ceramic) is placed on it. The artificial tooth looks like a real one: the implant is embedded in the bone, and the crown accurately mimics a real tooth in structure and color. A crown on an implant can replace teeth in any part of the jaw and correct various defects.

This method does not affect the neighboring teeth. When chewing, the load is transferred to the titanium root and the jawbone, promoting normal blood circulation in the bone and preventing its atrophy. Depending on the material and care, the crown can last up to 20 years, while the implant can last a lifetime. The construction feels like one's own tooth: it does not fall out and does not cause discomfort.

Procedure for Installing a Crown on an Implant

Steps for prosthesis with a crown and implantation:

1. The patient is administered anesthesia (the choice of anesthesia is discussed in advance).
2. TThe doctor makes an incision in the gum, prepares the site for the implant, treats it, and implants it.
3. TAfter implantation, the doctor screws in a protective screw and applies stitches. The screw prevents bacteria from entering the implant.

The crown is installed at different times after implantation:

• Immediately or after 3-7 days (immediate load);
• After 3-6 weeks (early load);
• After 3-6 months (late load).

The patient visits the clinic to remove the stitches and install a temporary crown for the rehabilitation period. After the implant has fused with the bone (3-6 months), the doctor places a gum former for 7-14 days. Then an abutment is attached, connecting the implant and the crown.

After 2 weeks, the orthopedist fixes the permanent prosthesis:

• The doctor takes an impression of the patient's teeth and sends it to the dental technician.
• The technician creates a plaster model, selects an abutment, forms the framework of the crown, and veneers it. The process takes up to two weeks.
• The finished tooth is sent to the clinic for fitting and fixation.

Why a Temporary Crown on an Implant is Necessary

There are two methods of temporary prosthesis with crowns:

1. The "temporary crown" is installed immediately or within 3-7 days after implantation.

The temporary crown serves the following functions:

• Improves the appearance of the dental row, especially important for front teeth.
• Restores the function of the lost tooth (with the "temporary crown," one can chew soft food).
• Prevents bone loss around the implant (the load from the crown is transferred to the bone).
• Promotes the formation of a beautiful gum contour.

2. The temporary crown is placed after complete osseointegration of the implant, one month before the installation of the permanent prosthesis.

• Testing the Functionality of an Implant With Sufficient Load
  An orthopantomogram can show that the implant has well integrated into the bone. However, after attaching the prosthesis to the implant, the bone and gum may change. Poor integration of the implant into the bone can lead to its loosening. A temporary crown helps to timely assess the condition of the implant, adjust the treatment, and prepare a permanent prosthesis considering the patient's bite characteristics.
• Restoring Chewing Function, Preparing for the Installation of the Permanent Prosthesis
  With the long-term absence of a tooth, the patient gets used to living without it, and the chewing load is redistributed to other teeth. A temporary crown helps to adapt to the new tooth and evenly distribute the chewing pressure. It is easily adjustable and helps to find the optimal structure of the chewing surface. In case of breakage, the temporary crown can be easily and inexpensively repaired.
• Forming an Aesthetic Gum Contour
  A gum former does not always create a natural shape of the soft tissues. A temporary crown contributes to creating an accurate gum contour around the implant.

Materials for Crowns

Metal-Ceramic

A good choice in terms of price and quality. Metal-ceramic crowns are strong and aesthetically pleasing, with high-quality ceramic cladding. They are relatively affordable.

The framework is made from non-precious (chrome-nickel, chrome-cobalt) or precious alloys (gold-palladium). They are coated with a layer of ceramic that imitates enamel. For front teeth, metal-ceramic with a gold alloy is recommended, giving the crown a natural yellowish tint. In the side areas, standard metal-ceramic can be used.

Advantages:

1. Reliable, last up to 15 years.
2. Strong, withstand high chewing forces.
3. Affordable.
4. Aesthetic, with high-quality porcelain coating.

Disadvantages:

1. The metal framework can be visible through the ceramic, affecting the appearance (especially with cheap alloys).
2. Risk of ceramic chipping. Not suitable for patients with bruxism.
3. Crowns without shoulder mass with a cheap framework can cause allergies. Shoulder mass eliminates this risk as the edges of the crown are covered with ceramic.

Zirconium Dioxide

This material is ceramic but comparable in strength to metal. Zirconium is strong, aesthetically pleasing (Multilayer), and hypoallergenic. Suitable for restoring both front and side teeth.

There are three types of orthopedic constructions made of zirconium dioxide:

• Classic – two-layered with a zirconium base and ceramic coating. Quite beautiful, but the ceramic can chip.
• Multi-layer – combines the strength of monolithic zirconium with excellent aesthetics, comparable to E-max glass-ceramic.
• Monolithic – entirely made of zirconium, without a ceramic coating. Very strong, but less of a natural appearance.

Advantages:

1. Durable, lasts over 20 years.
2. Hypoallergenic.
3. Aesthetically pleasing. Multi-layer constructions are semi-transparent, suitable for front teeth.
4. Strong. Monolithic zirconium withstands high loads, good for side teeth.

Disadvantages:

1. Expensive, significantly more costly than metal-ceramic constructions.
2. Too strong. Monolithic zirconium can lead to increased wear of the enamel of opposing teeth.
3. Risk of ceramic chipping in classic models.

E-max Ceramics

For an aesthetically pleasing smile, E.max glass-ceramics are the best choice. Its optical properties closely resemble natural enamel. In dentistry, there are three types of E-max ceramics:

Advantages:

1. Durable. Last over 15 years.
2. Biocompatible. Do not cause allergies and prevent wear on opposing teeth.
3. Aesthetic. They accurately replicate the color and transparency of natural teeth (especially E-max Press Multi crowns). They fit perfectly with soft tissues and do not create dark edges when the gum recedes.

Disadvantages:

1. Expensive. It Costs more than traditional metal-ceramics, but the price is comparable to metal-ceramics on a precious metal base.
2. Not suitable for molars and patients with bruxism.

Methods for Fixing Crowns on Implants

Crowns can be attached to implants in two ways:

Screw Method

The crown is connected to the abutment outside the mouth in the laboratory. A hole is drilled in the crown, through which a screw is inserted and screwed into the abutment. The screw and hole are covered with a composite. Then the construction is placed on the implant in the patient's mouth.

This method is reliable and convenient. If necessary, the crown can be quickly removed without pain. In rare cases, the screw may loosen, but this is easily corrected.

Cement Method

First, the abutment is attached to the implant in the patient's mouth, then the crown is fixed on it with dental cement.

This method has disadvantages:

• It is difficult to remove the crown, which can cause pain and damage the implant.
• Cement can collect microbes, affecting the implant and potentially leading to its rejection.
• Over time, the cement can weaken, leading to the loosening of the crown.

Comparison to Traditional Crowns

Crown on an Implant or on a Prepared Tooth – Which is Better?

In prosthetics on one's own teeth, two prepared teeth of the patient are used as the base for the prosthesis. This method is suitable if the tooth is damaged by 50-70%, has changed color, or requires aesthetic restoration.

If a tooth is completely lost, some patients opt for a dental bridge supported by two adjacent teeth. However, doctors often do not recommend this method, especially if the adjacent teeth are healthy. These teeth need to be prepared and the nerve removed, leading to faster wear under chewing pressure. Additionally, bone atrophy continues in the area of the prosthesis.

A crown on an implant is the best choice for restoring a lost tooth for several reasons:

• Restores the perfect aesthetics of the dental row.
• Prevents jawbone atrophy and promotes its regeneration.
• Distributes chewing pressure better than a bridge.
• Lasts for decades (the implant for a lifetime).
• Does not harm the health of adjacent teeth.