When it comes to treating cavities, most people immediately think of a dental filling. However, there are some situations that need more than a traditional filling. Depending upon the extent of decay in a tooth, your dentist may recommend a dental inlay or onlay as the optimum restoration. Understanding the differences between the two — and why either may be a more appropriate restoration than a filling or a crown — can help you have a better informed conversation with your dentist when discussing your options.
What is a Dental Inlay?
Also known as an indirect filling, a dental inlay is a filling that fits into the pits and fissures (grooves) of a tooth’s chewing surface. An inlay is fabricated in a dental lab as a single, solid piece of ceramic porcelain that fits the exact size and shape of the cavity, and matched to the shade of the tooth. It is secured in place with dental cement. It’s most often used as restoration for cavities that are centered in the tooth instead of along the outer edges (cusps), and have not progressed into more extensive decay.
Your dentist may recommend an inlay if the tooth’s biting surface meets the following criteria:
- Broken, fractured, or decayed teeth that do not affect the cusps of the tooth.
- The damage is extensive enough to need a large dental filling that could weaken the remaining structure.
- The injury level does not allow for the removal of enough tooth material to support mounting a crown.
Dental inlays are known for being more durable than traditional fillings — lasting as long as 30 years, as compared to five to 15 years for a filling.
Unlike a traditional filling, an inlay typically requires two visits to the dentist. During the first visit, your dentist will numb the treatment area with a local anesthetic and then drill into the affected tooth to clean out the decay. Once this is done, your dentist will take an impression of your tooth’s top crevice area and send it to a dental lab. A temporary filling will be placed, to be removed during the second appointment, when the inlay will be placed and cemented. Before it’s cemented, your dentist will make sure the fit is correct.
Your dentist may have specific post-procedure care instructions, but in general, the first 48 hours are key. Avoid foods and drinks of extreme temperatures, as well as sticky or hard foods. Stay with soft, simple nourishment for a few days to give your mouth a rest. You may feel numb or sore for a day or two after your procedure. This is normal, but if you have any concerns, contact your dentist.
What is a Dental Onlay?
An onlay fits over the tooth’s biting surface and is fabricated in a dental lab of a solid piece of porcelain, composite, resin, or gold. This type of restoration is used to repair a tooth that has been damaged by decay or injury. Onlays are similar to inlays but differ in the amount of tooth they cover. Onlays go over the cusp (or cusps) of the tooth, whereas inlays fill the space between cusps.
Dental onlays can be thought of as a middle ground between filling a cavity and removing part of your tooth to cap it with a crown. Onlays are similar to crowns but replace less of the healthy tooth, making them a less extreme option. They only cover the tooth’s chewing surface, which is why they’re sometimes known as partial crowns.
As Smile Generation explains, “Your dentist may recommend a crown if your tooth is broken, very worn down, or severely weakened from decay. However, an onlay is a more conservative treatment option and good for a tooth with more remaining structure.”
A dental crown is a tooth-colored prosthetic that fits over the entire tooth, down to the gumline. Once inserted, a crown can strengthen the tooth, improving its overall appearance and alignment in the mouth. One drawback is that because so much of the tooth structure needs to be ground down, the tooth can never again be without a crown. Our blog post — “What You Need to Know About Crowns” — covers this topic in detail.
Your dentist may recommend an onlay in the following situations:
- When a cusp of the tooth is damaged so an inlay or filling can’t be used.
- If you have a cavity on a tooth with a weak structure that may crack if restored with a regular filling.
- To avoid the removal of the amount of natural tooth structure usually required to place a crown.
The procedure for an onlay is similar to that of an inlay, requiring two visits to the dentist. Although there may be slight variations depending upon the dentist and the patient’s individual situation, the following procedure is typical.
During the first visit, the dentist will numb the treatment area with a local anesthetic and then drill into the affected tooth to clean out the decay, then prepare it for the onlay. At this time, an impression of the tooth will be made and sent to a laboratory to create the permanent restoration. Next, a temporary onlay will be placed to protect your tooth until your next appointment. The second will be scheduled after the onlay is fabricated. Your dentist will remove the temporary onlay, clean the tooth, place the restoration and ensure a good fit. After checking your bite, your dentist will permanently bond the onlay to your tooth and polish it to match your natural teeth.
Because an onlay covers the top surface of the tooth, taking care to protect the temporary onlay is important. Colgate recommends the following, although your dentist may have addition instructions:
- Avoid using flossing devices around the onlay so it’s not accidentally damaged or removed.
- Skip chewing sticky or hard items like gum, candy, nuts, or ice. [Our note: never bite down on hard candy or ice!]
- Avoid overly hot or cold food and beverages that could aggravate sensitive areas.
- Brush your teeth gently twice daily for two minutes.
- Use antiseptic mouthrinse to help avoid problems with your gums.
- Contact your dentist if the temporary onlay becomes dislodged or damaged.
Who is a Good Candidate for These Treatments?
As mentioned earlier, an appropriate candidate for a dental inlay would be someone who has a greater degree of tooth decay than a traditional filling can support. To be eligible for an inlay or onlay, there should be enough of your remaining tooth structure present to adequately support the restoration. Those with weakened teeth due to bruxism (teeth grinding) or a history of multiple dental procedures may also benefit from dental inlays or onlays.
However, the ultimate success of any type of dental restoration depends upon your commitment to maintaining a consistent oral hygiene program, and scheduling an appointment with your dentist twice yearly for an examination and cleaning.
At NK Family Dental, it is our mission to provide the highest quality and most compassionate oral care to our Chicago patients, including both dental and periodontal services. Our practice is trusted for advanced oral surgery procedures and comfortable root canal treatment.
Our team of experienced, dedicated dental professionals will help address your oral health concerns, and determine the best solution for you based on your individual situation. We strive to identify treatment options that fit your needs.
Our dental specialists include our general dentist, Dr. Nilofer Khan, our endodontist, Dr. Sabek, and our periodontist, Dr. Amir Danesh. Dr. Danesh is a board-certified periodontist and Diplomat of the American Board of Periodontology. He has contributed to the publication of two books, as well as published over 20 papers in prestigious dental research journals.
We understand that the main concern you may have is cost, which is why we accept all major PPO plans for dental insurance and also offer our in-house dental plan. Please see our financing page for more information.