Inlay Dental Fillings on Teeth Samples

Inlays Vs Onlays

You’ve probably heard of getting crowns or fillings put in place to fill in cavities and dental decay. However, you may not have heard of some of the alternatives, such as dental inlays and onlays.

Usually, fillings are used to fill in small cavities, while crowns are used when the decay is deeper or if there is a larger fracture to be covered up. However, there may be situations when a filling is not enough, and a crown is too much to protect dental decay. Dental inlays and onlays are what many dental professionals will then use if they need something “just right” to fill in those gaps. They are more substantial than fillings, but not as intrusive as a crown, which may involve reshaping the teeth in some way. 

But what is the difference between the two?

At their most basic definitions, an inlay fills in cavities and hollows in a tooth in the areas between the cusps. An onlay will not just fill in cavities in those spaces, but they can work for a larger area, including the cusps.  They work similarly to crowns, but they do not cover the entire surface of the tooth. They are both made from the same materials, and they both serve the same function, but they cover different areas of the tooth to properly protect when there is tooth decay. 

inlays vs onlays

What is Inlay and Onlay in Dentistry?

Inlays are molded and fitted into the chewing surface of a tooth that has been damaged through decay or injury. They are created using an imprint of the affected areas that are sent to a lab for manufacturing. An inlay will fit perfectly into the hollow of the tooth, but they do not affect the cusps. When the dentist takes the impression, they also attempt to best match the color of the tooth as closely as possible. This way when they are placed in the mouth they are not noticeable. The material used for an inlay can be either porcelain or a composite material that is stronger and more durable than traditional fillings. This makes inlays generally more expensive, but also longer lasting. A dentist chooses this option when a filling will not properly strengthen the surrounding tooth and the cavity requires stronger materials to fortify the tooth. 

Onlays are used for decay and damage to the cusps of a tooth as well as the biting surface. A dentist will choose an onlay when a cavity is too big to fill with standard amalgam fillings, or that the tooth could crack due to weakness. An onlay will shore up the strength of the tooth along with protecting the decaying area. Unlike an inlay, this area can include the cusps as well as the space in between. The dentist prepares the tooth in a similar fashion to a filling, by drilling out the cavity and cleaning up the area after placing a numbing anesthetic in the mouth. A temporary onlay is then placed over cavity, and the impression is sent for a permanent onlay to be manufactured. It is then placed in the mouth when it arrives. With an onlay, the tooth structure is preserved, whereas with a crown some filing and even removal of cusps may be necessary. They are also made of porcelain or a composite material. Onlays are also called “partial crowns” because they serve a similar function but they only cover a portion of the tooth, as opposed to the entire thing. 

inlays vs onlays

How Long Do Inlays and Onlays Last?

One of the main benefits of inlays and onlays is how durable and long-lasting they can be. You can expect an inlay to last anywhere between 5 and 30 years. Dental professionals cannot guarantee how long they’ll last due to a variety of factors. Some can undergo more wear and tear than others, and if they are not cared for, then they can get damaged or fail sooner than expected. 

One of the biggest factors is how well the patient approaches their dental hygiene habits after inlays are put in place. This means brushing twice a day, flossing every day, and following any special recommendations from the dentist. A patient must go to the dentist for follow-up visits to check on the stability and health of the inlays or onlays to make sure that they are firmly in place.

Along with proper hygiene, patients should do what they can to reduce wear and tear on the inlays and onlays. Grinding teeth can cause cracking and damage. If a patient is grinding in their sleep, then the dentist can provide nightguards or other solutions to lessen grinding or protect the teeth. Chewy or hard food can also affect the longevity of inlays and onlays. Hard food can crack the material, and chewy food that sticks to the material can cause the bonds to loosen. 

So, while there is no firm number when it comes to how long they will last, you should expect them to last longer depending on how well you take care of them and your overall oral health. 

How Much are Inlays and Onlays?

You can expect to pay more for an inlay or onlay than you would for a filling, but how much they cost will depend on several things. For instance, the experience and reputation of the dentist will matter, as will the material used in the making of the restoration. Inlays and onlays tend to cost a similar amount, but onlays can cost more if the restoration is more extensive. In general, you can expect to pay between $650 to $1,200 for each tooth that requires restoration. 

When it comes to materials, porcelain is the most expensive, since it looks the most like natural tooth enamel. Gold is the most noticeable, but it is also the most affordable. If you choose  a composite resin, you will pay less than with porcelain, but it can stain and get discolored as time goes on. It is also the least durable option. 

How much you pay will also depend on how much damage a tooth has suffered.

If it is especially deep or spread around a large area, then the costs can escalate. For the type of damage that an inlay will help with, the area is smaller and costs cannot expand as much as with onlays. 

Most people do not require sedation for inlays and onlays. The dentist will recommend local anesthesia, but some patients may be a bit squeamish and ask for sedation. If you do, there will be an additional cost factored in for this service. 

When you are getting dental work done, you probably want to have someone who is experienced and knowledgeable about the procedure. This includes getting inlays or outlays. You can expect to pay more depending on how experienced your dentist is, and how good their reputation is. You should expect to pay for quality workmanship. 

Is an Onlay Better Than a Crown?

The main difference between an onlay and an inlay is that an onlay will cover a larger area that an inlay cannot cover. An onlay can cover the cusps of the tooth, but an inlay fills in the spaces in between. This might sound a lot like a crown, and there are some similarities, but they serve different purposes. 

An onlay is used when the dentist determines that the restoration does not have to be as aggressive as it would with a crown. That means that more of the structure of the tooth can be preserved. A crown covers the entire tooth, and significant reshaping of the tooth is necessary to have one installed. An onlay can be more difficult to get right, which is why the skill and experience of the dentist are so important. So neither is necessarily better than the other, and a dentist will recommend what suits the situation the best. 

Are Inlays Better Than Fillings?

Just as with the onlay versus crown debate, there are several facets to determining if inlays are better than fillings. In general, inlays are better in that they can fill a larger cavity, and they are more durable. The amalgam in fillings can expand and contract depending on the temperature, for example. This can lead to cracking of the filling, or even the tooth itself. They are as durable as inlays, which can last for decades at a time. Inlays do not have this problem, and in fact will strengthen the tooth. This is because they are custom made by using an impression, so they fit perfectly into the cavity. They strengthen the tooth so much that in some cases it can handle up to 75% more chewing force than it could before the decay.

That said, one of the benefits of fillings for many patients is how quickly they can be put in place. With an inlay it will take at least two visits: one for the impression, and one for the placement after the inlay is built. The materials for fillings are in the office and can be finished in just one visit. They are less expensive, and more widely covered by insurance. The bottom line is that inlays will perform better than fillings, but that is also reflected in how much they cost. 

Is a Veneer an Onlay?

No, a veneer is not the same as an onlay. Onlays are used to fill and protect extensive damage to the teeth, including the cusps. A veneer is usually used to cover the front of the teeth in the areas where people can see when someone smiles. They are not usually used to fight against tooth decay, but for cosmetic issues like discoloration and shading. They do share some similarities, including how durable they are, but they serve different purposes and are not the same thing. 

Are Inlays and Onlays Covered by Insurance?

Inlays and onlays are covered by many insurance providers. The reason is because they are not strictly cosmetic. They are used to keep the tooth strong while conserving tooth structure as much as possible. Check with your insurance provider to see if you are covered. 

Inlays and onlays have some similarities, but serve specific, unique purposes. Many dentists consider them to be great alternatives to fillings, crowns, and other dental restoration options. 

Kate Brayman, DDS

8285 Jericho Turnpike Suite 3B, Woodbury, NY 11797


Dr. Kate Brayman
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