Dentistry
Cosmetic
Product Reviews
Updated on February 2, 2023
7 min read

Dental Inlays and Onlays

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Inlays and onlays are indirect dental restorations, which means they are made outside your mouth in a laboratory. These restorations are typically used when a cavity is too large for a simple filling.

Here are some benefits of inlays and onlays:

  • More resistant to fractures and damage than traditional cavity fillings
  • Stain-resistant
  • Improve the natural aesthetic and appearance of teeth
  • Custom-made to fit a patient’s tooth structure, color, and shape
  • Depending on the patient’s cavity and fracture risk, they can last many years 
image 12

What are Inlays?

A dental inlay is made of a solid material that is custom-fit to your tooth. It's usually used to fill the space in the center of your tooth that has been damaged by decay or injury. 

Depending on the cavity size and depth, inlays are either cast into shape with gold or milled into shape with porcelain. They can be shaped and colored to match your natural teeth.

An inlay is molded to fit into the grooves of your tooth. It does not extend over the cusps of the tooth. Inlays provide an almost invisible yet durable restoration for tooth damage.

What are Onlays?

Similar to inlays, dental onlays are made of a solid material that is custom-fit to your tooth. They can also be shaped and colored to match your natural teeth.

An onlay is larger than an inlay but smaller than a dental crown. It is used to fill a larger cavity that extends over the cusps of a tooth.

Dental onlays are generally used to repair more extensive damage. They are often recommended if you have a large cavity extending beyond the tooth's center.

Inlays vs. Fillings and Onlays vs. Crowns

Inlays, onlays, fillings, and crowns all have similar benefits. They're used to restore damaged teeth, protect them from further decay, and improve their appearance.

However, there are some key differences between the four:

Inlays vs. Fillings

Fillings are the most basic type of restoration. This treatment is used to fill small cavities and stop further decay. Fillings are quick and easy to place and can usually be finished in one visit.

On the other hand, inlays are similar to fillings, but they're used for slightly larger cavities. They are more durable than fillings because they are made of stronger materials like gold or porcelain. However, this means it takes longer to make them. Inlays can take around two visits to complete. 

Onlays vs. Crowns

If an inlay isn’t suitable because of the missing tooth structure, you may need an onlay instead. An onlay will cover the cusps of the tooth.

Crowns are the most complex out of the four treatments. This restoration covers the entire surface area of a tooth and is often recommended when you need extensive repairs.

What are Inlays and Onlays Made of?

Inlays and onlays can be made of gold, composite, or ceramic materials:

image 44

Gold

In the past, gold was the material of choice for inlays and onlays because of its strength. Since gold is extremely durable and has similar properties to teeth, it protects weakened teeth cusps caused by cavities and trauma.

Today, with the introduction of tooth-colored restorations, gold dental restorations are less desired.

Gold inlays are typically used if a filling repeatedly fractures. For esthetic reasons, you may choose composite or ceramic (porcelain) inlays over those made of gold. However, they are more prone to damage since they are more brittle than gold.

Some dentists recommend opting for gold inlays or onlays in areas of the mouth where appearance is not important, such as the back molars.

Advantages

  • Very strong and malleable
  • Extremely low chance of fracture
  • Stain-resistant

Disadvantages

  • Does not blend in with your natural tooth color
  • More expensive than other restorations
image 45

Ceramic (Porcelain)

Ceramic inlays and onlays can be made of porcelain. Dentists use porcelain to create tooth-colored restorations that mimic the color, shape, and function of natural teeth. 

Advantages

  • Strong and durable material
  • Less prone to fracture than traditional fillings
  • Blends in with the color of your natural teeth
  • Stain-resistant

Disadvantages

  • More fragile than gold restorations
  • Despite its strength, ceramic is a rigid material with an increased risk of fracture
image 46

Composite Resin

Composite inlays and onlays fill cavities too large for traditional fillings. They are an alternative to gold or ceramic restorations and perform the same functions.

Advantages

  • Stronger and less prone to fracture than traditional dental fillings
  • Tooth-colored (blends in with your natural teeth)

Disadvantages

  • Weaker than gold or porcelain restorations
  • Less malleable than gold restorations
  • Not stain-resistant

What to Expect During the Procedure

Here are the steps you can expect during an inlay or onlay procedure:

1. Cavity or filling removal (if necessary)

Often, inlays and onlays replace fractured or damaged fillings or decay. 

If there is an existing filling in your tooth, your dentist will remove it before placement. Cavitated tooth tissue is also removed, leaving a hole behind. 

Then, your dentist shapes this hole using specific parameters as a guide, allowing for easier placement of the inlay or onlay.

2. Impression of the tooth (inlay/onlay mold)

During the first visit, a mold is taken of the prepared tooth. You will also pick the restoration shade if ceramic is chosen during this visit.

3. Temporary filling placement

While the inlay or onlay is being prepared, a temporary filling is placed to seal the cavity. This helps prevent further decay and protects your tooth from thermal stimulation (sensitivity caused by cold or hot liquids).

4. Inlay/onlay placement

After the restoration is made, you will set up one more appointment with your dentist to have the inlay or onlay placed.

During this appointment, your dentist may or may not administer a local anesthetic to reduce pain and increase comfort. Then, the temporary filling material is pulled off the cavity, and the inlay or onlay is cemented into your tooth.

Dentists can usually remove the temporary filling and place the inlay or onlay without causing significant discomfort.

Porcelain and composite inlays and onlays can now be made in-office with CAD/CAM technology and milling machines like CEREC. Dentists use the same technology to make “same-day” dental crowns. In these cases, you would undergo steps one and two, skip step three, and go straight to step four, all within the same visit.

How Long Do Inlays and Onlays Last?

Dental inlays and onlays usually last many years with proper care. Inlays and onlays may not last as long in people who grind their teeth, develop cavities easily, and/or have certain medical conditions.  

What are Some Aftercare Tips for Inlays and Onlays?

The recovery time for inlays and onlays only takes a few days.

However, your teeth are still susceptible to plaque and oral bacteria build up over time. It is essential to practice good oral hygiene to keep the restorations clean and strong.

To reduce the chance of oral disease, dentists recommend the following tips:

Oral Hygiene

Inlays may extend into the interdental areas of your mouth (between your teeth). These are difficult areas to clean and require regular interdental cleanings.

Basic oral care practices are also necessary, such as:

  • Brushing twice a day
  • Flossing regularly
  • Rinsing with mouthwash to kill bacteria

Diet

Reduce sugar intake after inlay or onlay placement. In addition, dentists recommend avoiding highly acidic foods. This includes candy, coffee, dairy, dark fruits, and processed food. Sticky food that can dislodge or pull out your restoration should also be avoided.

Break Bad Habits

You should quit habits that can cause your restoration to crack or break. These usually include habits that involve chewing or biting down on hard objects.

Smoking is another habit that can damage your gums, especially around your new inlay or onlay, over time. 

Check-Ups

Inlays and onlays should be routinely checked by your dentist. During these appointments, your dentist will examine the restored tooth for signs of leakage, damage, and disease.

If your dentist finds any problems, they can offer preventative care to prolong the life of your inlay or onlay.

How Much Does an Inlay or Onlay Cost?

The cost of an inlay or onlay depends on the type of material used and where you live. Since inlays and onlays treat cavities and trauma-related dental conditions, insurance will cover part of the procedure.

Inlays and onlays are considered "major" dental procedures, meaning insurance can cover up to 50 percent of the cost. In this case, you will only pay a couple hundred dollars out-of-pocket.

The prices below reflect the cost of an inlay/onlay without insurance:

  • Inlay — $650-$1,200 (per tooth)
  • Onlay — $650-$1,200 (per tooth)

Summary

An inlay or onlay can help restore damaged teeth and prevent future problems. They're not permanent, but they can last several years, depending on how well you care for them. Remember to visit your dentist regularly to ensure their longevity.

Last updated on February 2, 2023
6 Sources Cited
Last updated on February 2, 2023
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
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  2. Blue Ocean Publishing Group.The Million Dollar Smile, Changing Lives with Cosmetic Dentistry.” 2018.
  3. Hollins, C.Basic Guide to Dental Procedures.” John Wiley & Sons, Inc., 2015.
  4. Fron Chabouis H, Prot C, Fonteneau C, et al. "Efficacy of composite versus ceramic inlays and onlays: study protocol for the CECOIA randomized controlled trial." Trials, 2013.
  5. Aspros A. "Inlays & onlays clinical experiences and literature review." J Dent Health Oral Disord Ther, 2015.
  6. Bustamante-Hernández N, Montiel-Company JM, Bellot-Arcís C, et al. "Clinical Behavior of Ceramic, Hybrid and Composite Onlays. A Systematic Review and Meta-Analysis." Int J Environ Res Public Health, 2020.
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