An inlay is an indirect restoration constructed of cast metal, porcelain/ceramic, or composite/resin that neither supports nor replaces a cusp or cusps of tooth. The inlay restoration is nothing more than a centric stop in that it provides no protection for the cusp tip as concerns lateral and/or protrusive masticatory excursionary forces.
An onlay is an indirect restoration (fabricated outside the oral cavity) that covers one or more cusps, extending through and beyond the cusp tip to the facial/lingual and proximal slopes of the covered cusps. It may be fabricated from any of the materials used for inlay restorations. It is implicit in this type of restoration that occlusion in all functional positions is supported by restorative material rather than the tooth structure of the covered cusps.
Dental inlays and onlays are used to repair decaying teeth that do not require extensive bridgework, or to replace older metal fillings. Most dental inlays and onlays are composed of porcelain, though some can be made from gold or composite resin. Patient that desire a natural smile often request porcelain inays and onlays, since they are highly undetectable.
Benefits of Dental Inlays and Onlays
In treating dental decay, inlays and onlays help to eliminate tooth sensitivity and eventual tooth loss. Inlays and onlays also offer the following benefits:
- Since they can be made from tooth-colored material, including porcelain and composite resin, inlays and onlays are virtually invisible.
- Unlike metal fillings, inlays and onlays will not expand or contract in response to temperature changes caused by hot or cold foods. This change in size can cause teeth to weaken or fracture.
- The use of inlays and onlays requires less tooth reduction than does the use of metal fillings. This allows dentists to conserve more of a patient’s natural tooth structure in the treatment process.
- Because of the way inlays and onlays are made, they help to strengthen teeth by up to 75 percent.
- The durable material from which inlays and onlays are made helps them last up to 30 years, much longer than that of conventional fillings.
- Inlays and onlays can replace silver fillings to create a healthier, more natural-looking smile.
- By saving decayed teeth, inlays and onlays prevent the need for more extensive treatment later on.