Restorative Dentistry
Inlays & Onlays
When a tooth has damage too extensive for a direct filling but does not require a full crown, an inlay or onlay offers a precisely fitted, lab-fabricated restoration that preserves as much natural tooth structure as possible.
What are inlays and onlays?
Inlays and onlays, sometimes called indirect fillings, are custom-made restorations fabricated in a dental laboratory and cemented permanently into or onto a back tooth. Unlike a direct filling, which is placed and shaped in a single appointment, these restorations are crafted outside the mouth under controlled conditions and then bonded in place.
The distinction between the two lies in where the restoration sits on the tooth:
Inlay
Fits within the cusps (the raised points) of the tooth, restoring the central portion of the chewing surface. Used when decay or damage is limited to this area and has not extended over the cusps.
Onlay
Extends over one or more cusps of the tooth. Used when damage is more extensive, covering a larger portion of the chewing surface, but still does not require the full coverage of a crown.
When inlays and onlays are used
Inlays and onlays occupy a middle ground in restorative dentistry. They are typically considered when:
- Decay or a fracture is too large to be reliably restored with a direct filling
- A significant portion of the tooth structure has been lost, but enough sound tooth remains that a full crown would remove more structure than necessary
- An old, large filling has failed or is showing signs of cracking and needs replacement with a more durable restoration
Your dentist will discuss the options with you and explain which restoration is most appropriate given the extent of the damage and the location of the tooth.
Materials
Inlays and onlays are commonly fabricated from ceramic (porcelain) or gold. The appropriate material depends on the location of the tooth, your bite, and aesthetic preferences.
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Ceramic / porcelain
Closely matches the natural colour of the tooth and is a common choice for teeth visible when smiling.
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Gold
Extremely durable, with a long track record. Often used in back molars where strength is a priority and appearance is less of a concern.
The procedure
Placing an inlay or onlay requires two appointments:
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Preparation and impressions (first appointment)
The tooth is numbed with local anesthetic, and any decay or damaged structure is removed. The tooth is shaped to receive the restoration, and impressions are taken. These are sent to a dental laboratory where the inlay or onlay is fabricated. A temporary restoration is placed to protect the prepared tooth in the interim, typically one to two weeks.
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Permanent placement (second appointment)
The temporary is removed, and the lab-fabricated restoration is checked for fit and bite. Once confirmed, it is bonded permanently to the tooth and polished. Any final bite adjustments are made before you leave.
How inlays and onlays compare to direct fillings
For smaller areas of decay, a direct composite filling placed in a single appointment is often the most appropriate choice. For larger restorations, inlays and onlays offer some practical advantages:
- Fabricated in a laboratory under controlled conditions, which can allow for a more precise fit and contour
- May be more durable than a large direct filling for teeth subject to heavy chewing forces
- Preserve more natural tooth structure than a full crown, which requires removing tooth material all the way around
The tradeoff is that inlays and onlays require two visits and a laboratory fee. Your dentist will recommend the restoration most appropriate for your situation.
Ready to restore your smile?
Call 306.374.7272 or request an appointment online.