INLAYS VS ONLAYS VS CROWNS

An inlay is classified as an indirect restoration, a filling material that is made out of the mouth.  Its material can consist of either porcelain, gold, or cured resin composite.  Fabricated in a dental laboratory, it is used when there is excessive lost of tooth structure that is too large to be restored by filling.  An inlay or onlay can also be used to establish proper occlusal forces with the opposing dentition by matching biomaterial wear.

inlays and onlay in BellevueAn onlay is similar to an inlay, except that this indirect restoration extends to replace one or more cusps of the tooth.

A crown in comparison is an onlay that covers ALL cusps of the tooth.

INLAY

An inlay is sometimes used when a tooth due to decay, cavity, or fracture needs a restoration that a traditional direct restoration (ie. composite or amalgam filling) would affect the tooth’s structural integrity.  An inlay can also be more advantageous compared to a composite restoration as the latter tends to shrink during light curing/polymerization, which may cause issues with marginal integrity; the former does not as the inlay is custom made by a dental laboratory.  Recent composite advances though, have made marginal adapatations much improved and less of an issue.

An inlay is also superior to the direct resin/amalgam restorations in that material choice has superb resistance to decay, precision marginal integrity and fit, improved cleansing ability, and often times better gingival health if the material is placed subgingivally (beneath the gum line).

ONLAY

An onlay is used when the tooth needing a restoration has one or more cuspal involvement, but not all cusps affected (i.e. a singular cusp fracture). The onlay is a more conservative restoration than a crown, while maintaining all the benefits of an inlay as described above.  And similar to an inlay, an onlay can be made out of porcelain, gold, or composite.

THE PROCESS

After the tooth is sufficiently prepared and decay and unsupported fractured structure removed, an impression is taken and sent to a dental laboratory or milling machine for a custom make.  Your dentist may decide to place a temporary material and have you return at a subsequent date to place the final prosthetic restoration.  The restoration is utimately cemented or bonded to the tooth.

If you have any questions about inlays and onlays, contact your dentist in Bellevue at (425) 614-1600!

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