An inlay is a custom-fabricated, indirect dental restoration fitted precisely into the prepared cavity of a posterior tooth, used to repair moderate decay or structural damage that exceeds what a direct composite filling can reliably address but does not require the full coverage of a dental crown.

Unlike a filling placed and shaped directly in the mouth, an inlay is fabricated outside the oral cavity — in a dental laboratory or via CAD/CAM milling — then permanently bonded into position. This indirect approach yields exceptional precision in marginal fit, occlusal contour, and interproximal contact restoration.

How an Inlay Is Placed

The procedure typically spans two appointments. At the first visit, the dentist removes diseased tissue and prepares the cavity, then records an impression or digital scan. A temporary restoration protects the tooth while the inlay is fabricated. At the second visit, the finished restoration is evaluated for fit and occlusal harmony before being permanently seated with dental cement.

Inlay Materials

Inlays can be fabricated from several materials, each with distinct clinical considerations:

• Porcelain (ceramic): Closely mimics natural tooth color; excellent esthetics and biocompatibility.
• Gold alloy: Exceptionally durable and wear-resistant; long considered the benchmark for longevity.
• Composite resin: Tooth-colored with moderate durability; a viable option for patients with metal sensitivities.

Clinical Significance

Inlays occupy a meaningful position in the restorative spectrum. Compared to large direct fillings, they offer reduced microleakage, a superior marginal seal, and greater resistance to occlusal forces. Compared to a crown, the inlay preparation is far more conservative — protecting healthy enamel and dentin that would otherwise be sacrificed.

An inlay restores only the area between the cusps — the central fossa — of the tooth. When coverage must extend over one or more cusps, the restoration is reclassified as an onlay. Both differ fundamentally from a crown, which encases the entire clinical tooth surface.

When a tooth has sustained too much damage for a filling but retains enough sound structure to avoid a crown, an inlay offers a conservative, long-lasting solution that restores both function and form — with well-placed porcelain or gold restorations routinely lasting 15 years or more with consistent maintenance.