Single Dental Implant Crown

What Is a Single Implant-Supported Crown?

A single implant-supported crown consists of three parts:

1. Implant

2. Abutment

3. Crown

Implant

An implant is a titanium screw that is surgically placed into the jawbone to replace the root of a missing tooth. Over time, the implant fuses with the surrounding bone through a process called osseointegration, creating a stable foundation upon which a crown could be placed. 

Several implant manufacturers are available. Most produce implants in a variety of diameters and lengths to accommodate different clinical situations. During treatment planning, your dentist will select the implant that best suits your individual needs.

Abutment
An abutment is an intermediate piece that allows the crown to connect to the implant. It is fastened to the implant with a small screw.  There are three types of abutments:

• Pre-fabricated Abutment
• Ti-Base Abutment
• Custom Abutment

Each type has advantages and disadvantages. The ideal choice depends on the position of the implant, the amount of available space, esthetic requirements, and the forces expected during function.

Pre-fabricated abutment:
A pre-fabricated abutment comes in a variety of standard sizes. It is generally the least expensive option; however, it has several disadvantages that may outweigh the cost savings and should only be used if a well-matched size can truly be found. More often than not, compromises must be accepted when selecting this approach and in some cases it may not even be an option, such as when the implant had to be placed at an unfavorable angle.

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Ti-Base (titanium base) abutment:
A Ti-Base abutment is also considered a prefabricated abutment but it differs significantly from conventional stock abutments. These abutments are available in only a limited range of sizes and are generally much smaller than traditional pre-fabricated abutments. In many situations, they are shorter than ideal. Because of their smaller dimensions, less surface area is available to retain the crown. A reduced bonding surface may increase the likelihood of the crown becoming loose over time. For this reason, careful case selection and proper fabrication techniques are especially important when using a Ti-Base abutment. Despite these limitations, Ti-Base abutments are widely used because they can provide excellent esthetics and allow crowns to be fabricated using modern CAD/CAM technology.

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Custom abutment:
A custom abutment is individually designed for a specific patient using digital technology. Rather than selecting the closest available size from stock abutments, the dental laboratory digitally designs the abutment to match the exact position of the implant and the surrounding tissue. This customized approach allows the emergence profile, contour, height and angulation of the abutment to be optimized for each case. As a result, the crown often achieves improved support, better esthetics, and more predictable long-term function. Although custom abutments generally cost more than pre-fabricated options, they frequently provide the best overall fit and are often recommended for highly esthetic areas or more complex clinical situations.

Crown
The crown is the visible portion of the restoration that you see in your mouth. It is custom fabricated to resemble a natural tooth in shape, size, color, and contour. Modern implant crowns are designed to restore both function and esthetics while blending naturally with the adjacent teeth. 

Crowns can be fabricated from a variety of materials, including metal, ceramic, or a combination of both. The ideal material depends on several factors, including the location of the implant, esthetic requirements, biting forces, available space, and your personal preferences.

How is the crown attached to the implant?

There are two ways to fabricate and attach the crown to the abutment:

Cement-retainedable implant crown: With this technique, either a pre-fabricated abutment, Ti-Base abutment, or custom abutment is first secured to the implant with a retaining screw.

The crown is then permanently or temporarily cemented onto the abutment. Depending on the clinical situation, either a weaker temporary cement or a stronger permanent cement may be selected.

A weaker cement may be preferred when future removal of the crown is anticipated, such as in cases where screw loosening or maintenance may become necessary.

A strong cement is preferred when an access channel is incorporated into the crown to allow direct access to the screw. In this situation, there is usually no need to separate the crown from the abutment because the screw head remains accessible.

One disadvantage of this type of restoration is that the crown and/or the abutment can become lose. This may occurs if the cement layer fails and/or if the screw unwinds. In other words, there are two possible points of failure. On a positive side, this type of a restoration allows for the use of a wide range of materials, such as gold, ceramic, Zirconia or porcelain fused to metal. It is often the preferred option to go this route when the strongest tooth color materials, such as Zirconia, are desired.  

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Screw-retained implant crown  (UCLA Crown) The abutment is custom made and porcelain is fused directly onto it. This creates a single seamless restoration without the need for cement. The restoration is attached directly to the implant using a small screw.

One advantage is that there is no cement layer that can fail. The only way the crown can loosen is if the screw itself loosens. Unlike cemented crowns, this type of restoration is highly unlikely to suddenly fall out. Screw loosening is typically a gradual process, allowing you to notice the problem before the restoration becomes dislodged. It is important to see your dentist promptly if you notice the crown is loose as prolonged screw loosening can increase the risk of metal fatigue and screw fracture.

Another advantage is the absence of junction between the crown and the abutment. Junctions are rarely completely seamless and it enhances plaque accumulation which can irritate the surrounding gum tissue. A UCLA crown is seamless and tissue friendly. 

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Comparison of different abutments:

Pre-fabricated Abutment

Advantages	Disadvantages
• Lower cost • Readily available • Simpler workflow	• Limited sizes and shapes • May require compromises in fit and aesthetics • Less ideal or impossible to use for difficult implant angulations • May not provide optimal crown retention • Excess cement may remain under the gum

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Ti-Base Abutment

Advantages	Disadvantages
• More cost-effective • Easier insertion • Crown is cemented outside the mouth	• Limited sizes • Often shorter than ideal • Reduced surface area for retention • Crown may loosen or fall off more easily

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Custom Abutment

Advantages	Disadvantages
• Custom fit for ideal gum contour • Maximum crown retention • Better aesthetics • Can correct challenging implant angles • Often the best long-term solution	• Higher cost

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Screw-Retained Crowns

Advantages	Disadvantages
• Easier to remove for maintenance • No excess cement under the gums	• Small screw access hole may be visible

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Cement-Retained Crowns

Advantages	Disadvantages
• No noticeable screw hole • In certain areas, better aesthetics	• Excess cement can irritate gums if not cleaned properly • More difficult to remove

Why Choose Lakeview Dental?

Every implant restoration is designed with long-term function, esthetics and maintenance in mind. Careful treatment planning, high-quality restorative materials and close communication between the dentist and dental laboratory help produce restorations that are attractive, durable, and easier to maintain over time. Our goal is to provide treatment that not only looks natural but also functions predictably for many years.

References

For patients interested in learning more, the following organizations provide reliable information regarding dental implants:

• Academy of Osseointegration (AO)

• American Academy of Implant Dentistry (AAID)

• American College of Prosthodontists (ACP)