Ceramic inlays and onlays

When decay or an old filling has destroyed a large part of a back tooth, an ordinary filling may not withstand the load: it cracks, chips and new decay forms underneath. A crown, on the other hand, requires reshaping the tooth on all sides. Dental inlays and onlays are an in-between option: they restore only the damaged part and keep healthy tissue. At UKRMED they are made as part of tooth restoration.

Photo: Jeffrey Dorfman, Wikimedia Commons, CC BY-SA 3.0

What is a dental onlay and an inlay

A ceramic inlay is a small restoration made in a laboratory from an impression or a digital scan and then bonded into the prepared cavity. Depending on the size of the defect:

• inlay - sits inside the tooth without covering the cusps (the raised points on the chewing surface);
• onlay - covers one or more cusps;
• overlay - covers the whole chewing surface.

Dental onlay vs crown and filling

• Compared with a filling. A large filling shrinks as it sets and withstands load less well. An inlay is made outside the mouth, so it matches the tooth precisely, fits tightly and is stronger.
• Dental onlay vs crown. For a crown the tooth is reshaped on all sides; for an onlay only within the defect. If the tooth is more than half destroyed or weakened after root canal treatment, a crown is more reliable.

A systematic review found that ceramic inlays, onlays and overlays have a high long-term survival rate: most of them last for years without replacement. The main possible complications are chipping and fracture of the ceramic, so an accurate bite and protection from grinding matter.

How an inlay is made

1. Diagnosis and treatment. The old filling and decay are removed. If the nerve is affected, root canal treatment comes first.
2. Preparing the cavity for the inlay shape.
3. Impression or digital scan of the tooth.
4. Temporary filling while the inlay is made.
5. Bonding. The inlay is tried in, bonded with adhesive cement (a special adhesive that bonds firmly to enamel), the bite is checked and it is polished.

Care

A ceramic inlay needs no special care: brush twice a day, floss and have a check-up every 6 months. If you grind your teeth, ask about a night guard to protect the ceramic.

Prices

Sources

1. Morimoto S., Rebello de Sampaio F. B., Braga M. M. et al. Survival rate of resin and ceramic inlays, onlays, and overlays: a systematic review and meta-analysis. J Dent Res, 2016. https://doi.org/10.1177/0022034516652848
2. Vagropoulou G. I., Klifopoulou G. L., Vlahou S. G. et al. Complications and survival rates of inlays and onlays vs complete coverage restorations: a systematic review and analysis of studies. J Oral Rehabil, 2018. https://doi.org/10.1111/joor.12695