Inlay and Onlay Restorations
Laboratory-made restorations that sit between a filling and a crown.
In Short: What Are Inlays and Onlays?
Inlays and onlays are pieces made in a laboratory to fit a particular tooth and bonded to it to restore a large missing part. They sit between a filling and a crown: they are chosen when the missing part is too large for an ordinary filling to stay sound, but limited enough not to require covering the whole tooth.
A few terms used on this page: Cusps are the small peaks on the chewing surface of back teeth. Restoration is the general name for treatments that replace a lost part of a tooth, such as fillings, inlays, onlays or crowns. The bite (occlusion) is the way the upper and lower teeth meet. A contact point is where the side surfaces of two neighbouring teeth touch.
The Difference Between an Inlay and an Onlay
An inlay sits in the hollow between the small peaks (cusps) on the chewing surface of a back tooth; it does not cover the peaks. An onlay, when the missing part reaches the peaks, also covers one or more of them. Neither surrounds the tooth on all sides, which is what distinguishes them from a crown, which covers the whole tooth.
When Does It Come Into Question?
The main situations are: when large old fillings need replacing; when decay that has spread under a filling has left a wide cavity; when one of the peaks of the tooth has broken; and when a tooth has a missing part after root canal treatment but does not need to be covered completely. The aim is to preserve as much of the sound part of the tooth as possible.
How It Differs From a Direct Filling
An ordinary filling is placed in the mouth in layers and hardened with a light. As the material hardens it shrinks slightly; the larger the cavity, the more this shrinkage can leave gaps at the edges, and the harder it becomes to create a good contact with the neighbouring tooth. Inlays and onlays are shaped outside the mouth on a model, which is a copy of the tooth. This allows the surface that touches the neighbouring tooth and the shape of the chewing surface to be created in a more controlled way.
The Treatment Process
It usually takes two appointments. At the first, decay and the old filling are removed, the tooth is shaped so the piece can sit on it, and an impression is taken. A temporary filling protects the tooth between the two appointments. At the second, the piece made in the laboratory is fitted, the bite is checked, and the piece is bonded to the tooth. The material may be ceramic or composite; the choice depends on where the tooth is in the mouth and the biting force on it.
Care Afterwards
How long the restoration lasts depends on oral hygiene, gum health and chewing habits. For people who clench their teeth, a protective guard worn at night may be advised. Cleaning between the teeth with floss or an interdental brush and regular check-ups help keep the join between the piece and the tooth sound.
When Should You See a Dentist?
See your dentist if, after the restoration, the tooth feels high when you bite; sensitivity lasts more than a few days or keeps increasing; you can feel a gap or rough edge at the margin with your tongue; the piece feels loose or comes off; there is a dark colour change at the margin; or there is pain in the tooth or swelling of the gum. If the temporary restoration comes off between the two appointments, report this without delay too; the prepared tooth should not be left unprotected.
Frequently Asked Questions
What is the difference between an inlay and an onlay?
Both are restorations prepared in the laboratory and bonded to the tooth; the difference is in the area they cover. An inlay sits within the hollow between the cusps of the tooth. An onlay covers one or more cusps in addition to that area. Which is suitable is determined by whether the tissue lost to decay or fracture extends to the cusps.
Why an inlay or onlay rather than a filling?
Once the loss of structure exceeds a certain width, shrinkage and marginal adaptation of a filling placed in layers in the mouth begin to present problems. Because inlays and onlays are produced outside the mouth on a model, the margin and the contact point can be formed under better control. This approach also removes less sound tissue than a crown.
Is an inlay/onlay or a crown needed?
The determining factor is whether the remaining cusps are thick enough to withstand chewing forces. If the cusps are sound, an inlay or onlay can provide a solution while removing less tissue. Where the cusps have thinned, a crack is present, or the tooth has had root canal treatment, full coverage comes into question. The distinction is made by clinical examination and, where required, radiological evaluation.
What material are inlays and onlays made from?
Glass ceramic or laboratory-processed composite is generally used. Ceramic transmits light in a way closer to natural tooth and is more resistant to surface wear; composite is more readily repairable and causes less wear to the opposing tooth. The choice is made according to the position of the tooth, the force it carries and the bite relationship.
The information on this page is for general information purposes and does not replace a clinical examination. The suitability, duration and alternatives of treatment can only be determined by your dentist after clinical and, where required, radiological evaluation.
This treatment is carried out at the clinic in Yeşilbahçe, Muratpaşa, Antalya. Location and directions.