When cavities are formed on your teeth or you have decayed tooth, dentists carve out the damaged areas and fill the tooth with special dental materials. This is what you have in mind when you hear repairing teeth with fillings.
However, you may have larger and extensive cavities due to dental decay and fractures. Or you may have some healthy parts of your tooth which are not still damaged. Thus, filling teeth with dental inlays and onlays are preferred over regular fillings in these situations.
Inlay and only dental restoration come as the best alternatives to fillings and also a conservative option instead of crown. Inlay and onlay remove more of your tooth structure than for filling but still carve less of your tooth compared with dental crown.
What is an inlay?

Dental inlay is the tooth repair technique for larger inner cavities and decays in teeth which the filling is prepared outside of the mouth and cemented in place. Dental inlay is a type of pre-molded filling that restores damages in the teeth with highly tough tooth-colored ceramic/porcelain or metal alloys such as gold.
Inlays are made according to the impression that taken from your prepared cavity of your affected tooth. As the name suggests, inlay is used for central damages in teeth which have remining undamaged parts on the sides or on upper parts.
What is an onlay?
Dental onlay is also a pre-molded filling that repairs the cusps or biting surface of your tooth. Similar to inlays, onlays are made in the lab and fitted in the prepared area of your tooth. Not only are onlays fill the internal part but repair the chewing surface of your teeth, the tip or upper tooth parts known as cusps.
Difference between onlay and inlay
Dental inlays are used to fill the central part of a damaged tooth, but dentists use onlays for repairing the lateral surfaces or chewing surface of a tooth, too. These biting or chewing parts are called cusps. Depending on the amount of damage, your dentist may restore the entire cusps or just one cusp in onlays.
How are the inlay or onlays are prepared?
Unlike regular fillings, which are already prepared and applied at same appointment, Dental inlay and onlay require more additional laboratory work and steps to be fitted into the grooves and cavities of your tooth. For inlay and onlay, a mold of the area of restoration is necessary and it is done by first taking an impression.
An important tip:Today, computer-aided design (CAD) and computer-assisted manufacturing (CAM) have decreased both time and difficulty of dental work. Dentists who use new CAD and CAM systems can deliver your Inlay and onlay fillings in a matter of hours.
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The steps for inlay and onlay preparation are:
- Dentist drills away the damaged part of your tooth
- Impression is taken from the carved location
- The impression is sent to the lab for casting the metal, ceramic or composite materials to get the mold of the restoration
- The materials is exposed to extreme heats or lights and other lab work to fabricate a much durable and strong inlay and onlay
- You are called for a try-in appointment and the inlay or onlays are cemented or bonded into the place.
- More finishing and polishing work is done. Your dentist ensures that there are not any rough edges and the surface of your filling is as smooth in its place and aligns with the other natural tooth structure.

Difference between dental inlay/onlay, dental fillings and crown
Dental caries, cavities and trauma can all cause irreversible damages to your teeth. When it comes to a treatment, your dentist will opt for the most suitable restoration that can be both pleasing and affordable.
- Dental filling
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Treatment with dental filling is the fastest and least expensive of other restorations. Your dentist drills the decayed portion of your tooth and fills the cavities with tooth-colored materials like composite resin or silver-color material known as amalgam filling.
Dental filling is indicated in case of smaller or medium sized cavities or when decay is not large enough to drill much of tooth structures. The process takes one dental visit.
- Inlay and onlay
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Repairing a tooth with inlay or onlay requires more tooth removal. It is best suited when some part of your tooth is still healthy and not decayed. Dental inlay and onlay are called indirect restoration since the procedure needs additional work to prepare the material in the lab. It is a much durable restoration because of these material preparation methods. Treatment with inlay or onlay needs at least two appointments. The first visit is drilling the decayed or damaged parts of your tooth and taking the impression. You wait for the preparation of custom-sized filling to be made. The second or the following visits goes around the application, try-in and finishing processes.
Dental inlay-onlay can have additional lab costs, so you will need to pay more than a regular dental filling. The most common dental inlay and onlay material is porcelain/ceramic, composite and metal alloys like gold. - Dental crown
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Having a crown is like putting a cap all over your tooth. Dental crown is the most extensive restoration of all, meaning your dentist removes all the outer layer of your tooth.
Crown restoration is indicated when your tooth is severely worn down due to cavities or dental caries, trauma and other risk factors.
Your dentist drills as much outer structure layer of your tooth until the inner healthy part of your tooth remains. Impressions is taken to get a custom fit cap that later will be fitted over your tooth.
Just like repairing tooth with inlay or onlay, dental crown is made in dental laboratory using highly professional methods for preparation. While you are waiting for your permanent crown to be made, you will be given temporary crown to prevent sensitivity or damages to the carved tooth.
Dental crown is made from all-ceramic, porcelain fused to metal or all-metal materials. Finally, the crown is fitted over your tooth. You can expect more costs but will enjoy a completely new tooth.
The benefits of inlays and onlays
Durable. Inlays and onlays are much durable and stronger against pressures and occlusal forces. They offer an excellent choice which preserve the other remaining part of your tooth.
Great fit and tight seal. Inlays and onlays provide a tight fill and seal the cavities in teeth from moderate to extensive. You will not have bacteria leakage and plaque accumulation because of ease of cleaning and sealing the surface of your teeth. Inlays and onlays go under high-tech and more workmanship before application. This way, you get a tough filling which your dentist has spent more time and skill to make a restoration in its perfect margin and occlusion proportions.
Color stability. Inlay-onlay fillings are stain-resistant and do not discolor easily. As long as you keep up with regular brushing and be careful about your eating and drinking, the color will keep its original shade for many years.
Beautiful and high esthetics. Inlay and onlay are available in tooth color forms that mimic your original natural tooth color. Porcelain is the most beautiful of ceramic choices that come in new glassy material ingredients. One the other hand, metal alloys like gold have long been used for its strength and esthetics features.
Preserve your tooth. Getting inlays or onlays not only repairs your teeth but also protects the other remaining weak parts of the damaged teeth. Your dentist gets rid of the caries by cleaning away the affected areas. They make space for white or metallic replacement depending on your needs. An inlay preserves the central areas, while an onlay provides strong cusps with great natural chewing surface for your teeth.
Better oral hygiene. You might know what happens when you don’t brush your teeth, yet the situation can become worse if you have cavities and decayed teeth. Inlays and onlays fill these decayed areas whether in top (cusps) or central grooves of your teeth. There are no more rough surfaces and uneven edges. Therefore, plaque buildups and food particles will not have chance to penetrate the restoration because of ease of cleaning and a much comfortable brushing on the smooth surface of your teeth.
Who can get inlay and onlay?
Getting inlay and onlay are the best alternative to fillings when you meet the right standards. Not everyone can receive inlay/onlay procedures. For example, children are not a good candidate because their upper part of teeth (the crown) are not fully grown and have low proportional dimensions.
If you have clenching habits and bruxism, you may end up with fractured inlays and onlays. Thus, using a mouthguard or maybe getting a crown is a better option.
Inlays and onlays will be the most suitable dental restoration if you:
- Have broken, fractured and chipped teeth due to cavities and tooth decay or injuries
- are looking for a long-lasting restorative procedure
- want to improve your smile with whiter, more beautiful and at the same time stronger filling
- have damaged fillings and if you are tired of recurrent repairs
- when the damage to the tooth is larger and extensive and fillings may put the other remaining tooth on danger, which requires a stable restorative procedure
- don’t want to remove too much of your tooth for a crown restoration
How much does an inlay and onlay cost?
On average, Dental inlays without considering insurance can cost you from $600 to $1,200 per tooth and onlays can cost around $600 to $1,500. The prices of inlays and onlays depend on some factors like:
- The materials used. Gold or some porcelain types can increase your restoration costs.
- The lab bills. Depending on the amount of work and techniques required, laboratory bills may add more to your costs
- The location and experienced dentists. Some dentists may have higher price range due to their experience, the quality of procedure they offer and their location and equipment.
- The type of tooth and inlay/onlay size. You will have higher fees when your inlay or onlay have larger sizes, which means larger cavities and more material. Teeth in far back like molar are more difficult to restore, so you can expect higher prices. In addition, whether you want an inlay or onlay will impact the prices, too.
Does insurance cover inlay and onlay?
You will have part of the costs reimbursed depending on the rate of reimbursement, your insurance company and the area you live.
Dental inlays and onlays can be categorized in teeth health issues similar to ordinary dental fillings and other regular dental services. This means more reimbursement rate and lower costs. The percentages for the regular dental services can reduce your cost by 50 or even 80 percent of the total expenses.
However, some insurance providers may also consider inlays and onlays in other categories like cosmetic dental services. In that case, you have to pay all the costs out of the pocket.
Ask your dentist for methods of payment in any case. Your dentist may offer more manageable and flexible payment options which will not be a financial burden. While you will have the benefit of a healthy tooth and more attractive look for your smile, the dentists can arrange costs that can keep you within your budget.