Dental Onlays | Conservative Tooth Restoration

Onlays

Dental onlays are a modern and conservative prosthodontic solution for the restoration of posterior teeth that have suffered extensive damage.

They are designed to restore the strength, function, and anatomy of the tooth while preserving as much healthy tooth structure as possible.

Thanks to their precise fit and the use of advanced materials, onlays provide a stable and aesthetically natural result, offering a higher-quality solution than a filling and a more conservative alternative to a full crown.

What Are Dental Onlays

Dental onlays are indirect restorations fabricated outside the mouth and bonded to teeth with significant loss of tooth structure.

They are indicated when a simple filling is not sufficient, but full coverage with a crown is not necessary.

Their purpose is to reinforce the remaining tooth structure and restore normal chewing function.

When Are Dental Onlays Used

Onlays are primarily used on posterior teeth, where chewing forces are higher.

They are recommended in cases of extensive wear, large or failing fillings, fractures, or altered tooth anatomy that requires a more durable solution than a direct restoration.

The decision to use an onlay is made following a detailed clinical evaluation and individualized treatment planning.

Advantages of Dental Onlays

Dental onlays offer high strength, excellent fit, and long-term stability.

At the same time, they allow for the preservation of more natural tooth structure compared to full crowns.

Their color and morphology are customized to blend seamlessly with the natural tooth, resulting in a harmonious and natural appearance.

Materials Used for Dental Onlays

Modern dental onlays are fabricated from advanced ceramic or hybrid materials that combine strength with excellent aesthetics.

Material selection depends on the functional demands of the tooth and the desired aesthetic outcome.

The use of digital dentistry and CAD/CAM technology ensures exceptional accuracy and optimal adaptation.

Dental Onlays and Minimally Invasive Prosthodontics

Dental onlays are a key component of minimally invasive prosthodontics, as they aim to preserve the natural structure of the tooth.

Modern prosthodontic philosophy emphasizes strengthening damaged teeth without removing additional healthy tooth structure beyond what has already been lost.

Advances in dental materials and adhesive techniques allow onlays to achieve high durability, excellent aesthetics, and conservative tooth preparation.

Stages of Onlay Fabrication

Two appointments are typically required for the delivery of a dental onlay.

During the first visit, any old restorations and decay are removed, the tooth is properly prepared, and a digital impression is taken.

At the second visit, the onlay is bonded using specialized adhesive resin materials.

A short interval of a few days separates the two appointments, during which the tooth is protected with a temporary restoration.

BEFORE and AFTER

Click the arrow to the right for more photos of each case

After

We bonded to the teeth, ceramic onlays that filled in the missing part of the tooth without grinding it further.

If we had opted for the crowns, the teeth would have had to be ground down much more and the remaining tooth substance would have been minimal.

The restoration replaces both the occlusal part of the tooth as well as the buccal and this is why it is also called vonlay

Δόντια με διάβρωση, μετά την θεραπεία με επένθετα

Before

Onlays can be used to fill in the missing part of the tooth without removing more tooth structure.

In this case, the teeth had been significantly worn down by erosion and much of the tooth substance had been lost.

After

Ceramic onlays were placed on the posterior teeth on both sides of the upper jaw.

The teeth regained their correct shape and our patient’s smile regained the confidence it had lost.

Διάβρωση δοντιών μετά την θεραπεία με κεραμικά επένθετα, χαμόγελο ασθενούς

Before

The smile of the patient in the photo was very hesitant prior to treatment as the back teeth had significant erosion and looked as if they were missing.

The patient did not want crowns on his teeth as they would have had to be ground down further.

Ceramic vonlays

After

Composite onlays, bonded to the remaining tooth structure, restored the teeth to their original shape while preserving the tooth structure.

Ενδοδοντικά θεραπευμένα δόντια μετά την αποκατάσταση με επένθετα

Before

The molars in the photo had undergone endodontic treatment (root canal) and needed to be restored.

If we chose to restore them with crowns, we would also have to grind down the little tooth structure that was left.

Then the tooth would definitely need a post and core.

Composite resin onlays

After

Ceramic onlays protected the teeth, gave them a normal anatomy and did not remove any additional tooth substance.

Here, the ceramic onlays in the posterior teeth were part of a comprehensive treatment plan.

Αποκατάσταση οπίσθιων δόντιων με διάβρωση με κεραμικά επένθετα

Before

The patient with tooth erosion had lost a large amount of tooth structure.

The teeth were sensitive, old fillings protruded from the chewing surface of the teeth and some teeth had decay.

Ceramic onlays for a patient with teeth erosion

Questions

Which teeth are dental onlays placed on?
Dental onlays are placed on natural posterior teeth that have lost a significant amount of tooth structure. They are indicated when a simple filling cannot provide a stable and long-lasting result.
Why is an onlay better than a filling?
An onlay offers greater precision and higher strength compared to a large filling. It helps protect the tooth more effectively and preserves its natural anatomy, especially in cases of extensive damage.
Why choose an onlay instead of a crown?
An onlay is a more conservative solution, as it preserves more natural tooth structure compared to a full crown. In selected cases, it can provide adequate restoration without the need for complete tooth coverage.

Do all large fillings need to be replaced with onlays?

No. An onlay is recommended when tooth structure loss is extensive or when the tooth requires additional reinforcement. Each case is evaluated individually.

Is a crown always preferable to an onlay?

If a tooth already has a crown, an onlay cannot be placed.
Onlays are used only on natural teeth.
When tooth structure loss is severe, a crown may be the only suitable option.
What materials are dental onlays made from?
Dental onlays are fabricated from tooth-colored materials, such as ceramics or advanced composite materials. Material selection depends on the functional demands of the tooth and clinical requirements.
Are there any disadvantages to dental onlays?
Like all prosthetic restorations, onlays require proper case selection, design, and fabrication. Their suitability is determined by the dentist based on the specific needs of each case.
What materials are the onlays made of?
Onlays are made of porcelain or polymer materials that match the colour of the tooth.

The choice of material depends on
- the size of the restoration,
- the position of the tooth in the dental arch
- and the presence or absence of bruxism
- the patient’s finances
Are there any disadvantages to onlays?
The disadvantages of the onlay are that
- it takes two appointments
- it is a more expensive than a filling