A dental inlay is a custom-made restoration that fits inside the chewing surface of a tooth, filling the space between its cusps (the raised points on top of your molars). Unlike a standard filling, which is molded directly inside your mouth while soft, an inlay is crafted outside the mouth in a dental lab, then bonded into place for a precise, durable fit. Inlays typically cost $650 to $1,200 per tooth and can last up to 30 years with good oral hygiene.
How an Inlay Differs From a Filling
A regular filling starts as a pliable material that your dentist packs directly into a cavity and shapes by hand. It works well for small cavities and minor chips, but it has limits. When decay removes a larger portion of the tooth’s chewing surface, a direct filling may not hold up under the repeated force of biting and chewing. The material can crack, wear down, or pull away from the tooth’s edges over time.
An inlay solves this by being manufactured to match the exact shape of your cavity. Your dentist takes an impression of the prepared tooth, sends it to a lab (or uses an in-office milling machine), and the inlay comes back as a solid, precisely shaped piece. Because it’s made from stronger materials and fits more tightly than a hand-packed filling, it holds up better in teeth that take heavy chewing loads. The bonding process also helps seal the restoration to the tooth, which can actually reinforce the remaining tooth structure rather than just plugging a hole.
Inlay vs. Onlay vs. Crown
These three restorations cover different amounts of tooth. An inlay sits entirely within the grooves of the chewing surface, between the cusps. An onlay covers those same grooves plus one or more cusps. A crown caps the entire visible portion of the tooth. Your dentist chooses among them based on how much healthy tooth structure remains.
Inlays work best when the outer walls of the tooth are still intact but the cavity between them is too wide for a standard filling to reliably hold. Once the damage extends over the cusps, an onlay becomes the better option. And when so much of the tooth is compromised that its walls can no longer support a bonded restoration, a full crown is typically necessary. Inlays preserve more of your natural tooth than either onlays or crowns, which is generally better for long-term tooth health.
What the Procedure Looks Like
Getting an inlay usually takes two visits. At the first appointment, your dentist removes the decayed or damaged portion of the tooth and shapes the cavity with specific geometry: slightly angled walls, rounded internal corners, and enough depth to allow at least 2 millimeters of restoration material at the biting surface. The goal is to remove only what’s damaged while creating a shape the inlay can lock into securely.
Next, your dentist takes a detailed impression of the prepared tooth. A temporary restoration goes over the cavity to protect it while the lab fabricates your inlay, which typically takes one to two weeks. At the second visit, the temporary comes off, the inlay is test-fitted, and then it’s permanently bonded to the tooth using dental adhesive. The entire process is done under local anesthesia, so it feels similar to getting a filling.
Some dental offices now have same-day milling technology that can scan, design, and cut an inlay in a single appointment, eliminating the need for a temporary and a return visit.
Materials Used for Inlays
Gold was once the standard material for inlays, and it’s still an option. Gold is extremely durable, gentle on opposing teeth, and resists corrosion. Its obvious drawback is appearance: it’s clearly visible when you open your mouth.
Most patients today choose tooth-colored options. Porcelain (ceramic) inlays match the color of natural teeth closely and bond chemically to tooth structure, which strengthens the overall restoration. They’re hard and resist wear well, though they can chip under extreme force. Composite resin inlays are also tooth-colored and tend to cost slightly less than porcelain, though they may not last quite as long under heavy use. Your dentist can help you weigh aesthetics, durability, and budget when choosing a material.
When an Inlay Is the Right Choice
Inlays fill a specific gap in the range of dental restorations. They’re recommended when a cavity or area of damage is too large for a direct filling to hold up reliably, but not extensive enough to justify shaving down the tooth for a full crown. The classic scenario is a wide cavity on the chewing surface of a molar where the outer walls of the tooth are still structurally sound.
Dentists sometimes describe this in terms of “isthmus width,” which is the distance between the inner walls of the cavity. When that space gets wide relative to the overall tooth, a direct composite filling becomes more prone to fracture. An inlay, being a single solid piece made from stronger material, handles that stress better. If you’ve had a large filling that cracked or fell out repeatedly, an inlay is often the next step up.
Advantages Over Standard Fillings
- Durability: Inlays made from porcelain or composite resin can last up to 30 years, significantly outlasting most direct fillings.
- Tooth preservation: Only the damaged portion of the tooth is removed, leaving as much healthy structure as possible.
- Precise fit: Because the inlay is custom-manufactured rather than hand-shaped, it fits the cavity more accurately, reducing gaps where bacteria could get in.
- Structural reinforcement: The bonding process can strengthen the remaining tooth, whereas large fillings sometimes weaken it.
Drawbacks to Consider
The biggest downside is cost. Inlays run $650 to $1,200 per tooth, compared to a few hundred dollars for a standard filling. The custom fabrication and higher-quality materials account for most of that difference. Dental insurance typically covers 50 to 80 percent of the cost, depending on how your plan classifies the procedure. Plans that treat inlays as a “basic” service may cover 80 percent after your deductible, while plans categorizing them as “major” restorative work typically cover 50 percent. With good coverage, your out-of-pocket cost can drop to as little as $10 to $100.
The two-visit process can also be inconvenient if your schedule is tight, though same-day options are becoming more widely available. Some patients experience temporary sensitivity to hot and cold after the inlay is placed, but this usually fades within a few weeks as the tooth adjusts.