Conservative Inlay and Onlay design and fabrication


The most common indication for inlays or onlays is to restore the grossly broken-down teeth which cannot hold conventional fillings.

The basic difference between Inlays and onlays is that the inlays lie only on the inside of the tooth within the cavity while the onlays extend into the biting surface of the tooth. On the other hand, crowns cover the whole biting surface of the tooth.

Indications for Inlays and Onlays

  • When it’s difficult to get an acceptable contour for tooth preparation.
  • When the repeated fracture is experienced with a normal tooth filling and composite bonding.
  • When there’s a risk of damaging the inner layers of the tooth, especially the pulp during the preparation for a crown.

Benefits of Inlays and Onlays

  • Enable preservation of healthy tooth structure as they are less invasive compared to crowns and bridges.
  • They rarely cause endodontic complications/pulpal damage to the teeth.

The process of fabricating Inlays and Onlays

  1. Prepare the tooth to remove the damaged tooth substance.
  2. An impression of the preparation is taken and sent to the laboratory.
  3. Inlays/onlays will be fabricated on the impression using different materials like gold, laboratory composites, or ceramic.
  4. Inlays/onlays will be polished and checked for irregularities.
  5. Once the inlays/onlays are fabricated your dentist will check how it contacts with the opposing arch during function and do necessary adjustments.
  6. The inlays/onlays will then be cemented onto the prepared cavity.

Types of Inlays and Onlays according to the material

Gold was the material of choice for inlays and Onlays for a long time. Even though gold is the most durable material due to its high strength, it is not a very aesthetically pleasing material because of its colour. With the advancement in dentistry, tooth-coloured materials like laboratory indirect composites and ceramics are available in the market. The major drawbacks of the composite are,

  • The accuracy of fit is significantly less than restorations made in either ceramic or gold.
  • They can absorb dietary stains after a few years which significantly affects their appearance.

The Wonder of Ceramic Inlays and Onlays

Ceramics have gained a lot of fame due to their advantages. Ceramic Inlays or Onlays are indicated where the aesthetic demands of the patient are high. The colour matching of modern porcelains impressively allows the margin between the tooth and material to be almost imperceptible. Yet, the margin might look obvious at times because blending is difficult.

Ceramic is a hard material and has high wear resistance though it’s brittle in thin sections. 2mm thickness will provide adequate strength for relatively a long duration.

The major drawback of ceramic is that it can be abrasive to the opposing dentition when used on biting surfaces if the glaze is lost and the restoration has been adjusted.

After the placement of inlays or onlays, it’s essential to follow the normal routine of dental hygiene in order to avoid any future complications.

You should brush and floss your teeth regularly with fluoridated toothpaste, especially at night. Meet your dentist or one of our cosmetic dentists at London Specialist Dentists as soon as possible if you notice any changes like discolourations and swelling around the restored tooth or if you get any symptoms like pain and discomfort because these might hint that there’s a leak under the inlay or onlay.