Restoring teeth
Inlays and Onlays
Inlays and onlays are restorations made outside the mouth and bonded into the tooth. They are considered when the damage is too large for a direct filling but not so extensive that the whole tooth needs a crown.
- Visits
- One or two, depending on how it is made
- Material
- Ceramic or composite
- Impression
- Intraoral scan
- Where
- Mostly premolars and molars
What is it?
An inlay fills the space between the cusps (the raised points on the biting surface). An onlay also covers at least one cusp, protecting a wider part of the tooth. Both are custom-made and bonded to the tooth with adhesive cements.
In a digital workflow the tooth is captured with an intraoral scanner, the restoration is designed on a computer (CAD) and produced from a ceramic or composite block (CAM). Depending on the system used and the case, it is either made the same day or with laboratory support.
Well-maintained ceramic inlays and onlays usually last many years; the most common problems are chips or cracks in the ceramic. How long they last depends on home care, grinding habits and regular check-ups. We compare fillings, inlays and crowns in this guide.
When can it be considered?
- Large old fillings that need replacing
- Back teeth that have lost a cusp
- Teeth weakened by cracks or fractures
- Protecting a tooth after root canal treatment in suitable cases (onlay)
Examination and planning
The examination looks at how much healthy tooth remains, whether there are cracks, your bite and any grinding habit, with X-rays when needed. This determines whether a direct filling, an inlay or onlay, or a crown is the right choice.
For limited damage a composite filling may be enough. If much of the tooth is lost or it has extensive cracks, a crown may be more suitable. Inlays and onlays sit between the two and aim to preserve as much healthy tooth as possible.
How the process works
Examination and X-rays
The condition of the tooth and the right restoration are decided.
Preparation
Old filling material and decay are removed and the tooth is shaped.
Digital scan
The tooth and opposing jaw are scanned and the bite recorded.
Design and manufacture
The restoration is designed and made; a temporary filling is placed if needed.
Try-in and bonding
Fit and contacts are checked before bonding and polishing.
Digital tools that may be used
- Intraoral scan
- A digital model of the prepared tooth and opposing teeth is captured without impression material.
- CAD (computer-aided design)
- Shape, contacts and bite are designed on screen.
- CAM (computer-aided manufacturing)
- The design is produced from a ceramic or composite block; the method depends on the case.
- Adhesive bonding
- The restoration is bonded to the tooth with adhesive cements.
Aftercare
Recommended
- Brush twice a day and clean between the teeth
- Wear a night guard if you grind
- Keep regular check-ups
Best avoided
- Cracking very hard foods such as ice, bones or hard sweets on the restored tooth
Whether a treatment suits you can only be decided after an examination. Timelines and stages vary from person to person.
Frequently asked questions
Can an inlay or onlay be done in one visit?
It depends on how it is made and on the case. With digital design and in-practice manufacturing some cases can be finished the same day; others need two visits because of a laboratory stage.
How is a ceramic inlay different from a composite filling?
A composite filling is shaped directly in the mouth. A ceramic inlay or onlay is made outside the mouth and bonded in, which allows the shape and contacts of a larger restoration to be rebuilt in a more controlled way.
Can an onlay be used after root canal treatment?
In suitable cases, yes. Root-filled teeth can be weaker, and an onlay that covers the cusps can help protect them. If very little tooth remains, a crown may be advised.
Why is a crown sometimes recommended instead?
If most of the tooth is lost, there are extensive cracks or the colour of the tooth also needs changing, a crown may be the better option. The decision is made after the examination and X-rays.
Related articles
Intraoral Scanner vs Traditional Impressions: Accuracy and Comfort
An intraoral scanner records your teeth in 3D without impression putty. Here is how it compares with traditional impressions on comfort, time and accuracy, and where conventional methods are still preferred.
Inlays and Onlays Explained: Filling vs Inlay/Onlay vs Crown
Choosing between a filling, an inlay or onlay and a crown depends mainly on how much healthy tooth remains. Here are the differences, how ceramic restorations are made and what studies show.
Veneers or Crowns? How the Right Restoration Is Chosen
A veneer and a crown are different restorations, and zirconia is a material rather than a treatment. This guide untangles the terms and explains the clinical factors behind the choice.
Related treatments
All treatments- incisors, canines, premolars, molarsComposite Fillings and BondingTooth-coloured composite used to treat decay, repair chips and make small cosmetic changes, usually in a single visit.
- incisors, canines, premolars, molarsCrowns and BridgesCrowns that cover the whole tooth and bridges that replace a missing tooth using the neighbouring teeth, made from materials such as zirconia or glass-ceramic.
- incisors, canines, premolars, molarsRoot Canal TreatmentTreating an inflamed or infected tooth nerve (pulp) by cleaning and sealing the root canals so the natural tooth can be kept.
Questions about inlays and onlays?
You can send your questions on WhatsApp or reach the practice by phone.