When a tooth is damaged by decay or wear, the right restoration depends on how much healthy tooth structure remains. A small area may be repaired with a filling, while a significantly weakened tooth may need a crown. But there are situations that fall somewhere in between.
Dental inlays and onlays are restorative options designed to repair certain damaged teeth while preserving as much healthy tooth structure as possible. They can be useful when a standard filling may not provide enough support but the tooth does not necessarily require the more extensive coverage of a full dental crown.
For patients throughout the Greater Phoenix area, understanding how inlays and onlays work can make restorative treatment recommendations easier to follow. The best option depends on the location and extent of the damage, the strength of the remaining tooth, your bite, and your overall oral health.
What Are Dental Inlays and Onlays?
Dental inlays and onlays are custom restorations used to repair portions of a damaged tooth. They are generally created to fit precisely into or over the affected area rather than filling the space directly during the initial preparation of the tooth.
An inlay typically fits within the grooves of the chewing surface of a back tooth. An onlay covers a larger area and may extend over one or more of the raised portions of the tooth, known as cusps.
Both are designed to restore damaged tooth structure and help the tooth function properly. Which one is appropriate depends on how much of the tooth needs to be repaired.
Because they can restore a specific portion of a tooth rather than covering the entire visible surface, inlays and onlays may allow healthy tooth structure to remain intact when clinically appropriate.
What Is the Difference Between an Inlay and an Onlay?
The primary difference between an inlay and an onlay is the amount of the tooth that the restoration covers.
An inlay is generally contained within the chewing surface of the tooth. Imagine the valleys or grooves located between the raised cusps of a molar. When damage is limited primarily to this central area, an inlay may be considered.
An onlay extends farther. It can cover the central portion of the tooth along with one or more cusps that have been weakened or damaged.
Because an onlay covers more structure, it can provide additional support when the damage extends beyond the area that would normally be restored with an inlay.
Your dentist determines which option is appropriate after examining the tooth and evaluating the extent of decay, cracking, wear, or previous dental work.
Why Would a Dentist Recommend an Inlay or Onlay?
Inlays and onlays can be useful when a tooth needs more restoration than a traditional filling may comfortably provide, but enough healthy structure remains that complete crown coverage may not be necessary.
For example, a back tooth may have a larger area of decay while still having strong surrounding walls. A dentist may determine that a custom inlay or onlay can restore the damaged section while preserving those healthy portions.
Previous dental work can also influence the recommendation. If an older filling breaks down or decay develops around it, the dentist must evaluate how much healthy tooth structure remains after the old material and decay are removed.
The goal is to choose a restoration that provides the support the tooth needs without unnecessarily removing healthy structure.
How Are Inlays and Onlays Different From Fillings?
A dental filling is typically placed directly into a prepared cavity and shaped within the tooth. Fillings are especially useful for smaller areas of decay or damage where plenty of healthy tooth structure remains.
Inlays and onlays are custom restorations designed to fit the specific shape of the prepared tooth. They may be considered when the damaged area is larger or when the chewing surface requires more support than a standard filling is expected to provide.
This does not mean an inlay or onlay is automatically better than a filling. A smaller cavity may be most appropriately treated with a conservative filling.
The decision depends on the individual tooth. Dentists look at the size and location of the damage, remaining enamel, chewing forces, existing dental work, and the likelihood that the restoration can provide appropriate long-term support.
How Are Inlays and Onlays Different From Dental Crowns?
A dental crown covers most or all of the visible portion of a prepared tooth. Crowns are often recommended when a tooth is extensively weakened, fractured, heavily restored, or requires significant structural reinforcement.
An inlay or onlay covers less of the tooth.
This distinction can be valuable when damage is significant enough to need a custom restoration but does not extend throughout the entire tooth. Preserving healthy enamel and tooth structure whenever practical is an important consideration in restorative treatment planning.
However, there are situations where a dental crown provides more appropriate protection. A tooth with extensive fractures, very large previous restorations, or significant structural loss may need broader coverage.
Your dentist can show you where the damage is located and explain why one type of restoration is being recommended over another.
What Types of Tooth Damage May Be Treated With an Inlay or Onlay?
Inlays and onlays may be considered for several types of damage involving back teeth.
One common reason is moderate tooth decay. If a cavity has grown beyond what the dentist considers ideal for a basic filling but has not damaged enough of the tooth to require a crown, an inlay or onlay may be an option.
They can also be considered when an older filling fails. Fillings can wear, crack, loosen, or develop decay around their edges over time. After removing the old restoration, the dentist evaluates the remaining tooth to determine what type of repair will provide appropriate support.
Certain cracks, chips, or worn areas may also be treated with an onlay if the damage affects part of the chewing surface or one of the tooth’s cusps.
Not every damaged tooth can be treated this way. Deeper fractures, infection, extensive decay, or problems involving the tooth pulp may require a different treatment.
What Happens During the Evaluation?
Before recommending an inlay or onlay, your dentist needs to understand what is happening inside and around the tooth.
The evaluation typically includes a visual dental examination. Your dentist may check the tooth for visible decay, fractures, worn areas, damaged fillings, sensitivity, or changes in the way your teeth come together.
Dental X-rays may also be recommended. X-rays can reveal decay between teeth or underneath existing restorations and help your dentist evaluate areas that cannot be seen during a routine visual examination.
Your symptoms matter too. Tell your dentist if you experience pain when chewing, sensitivity to temperature, discomfort with sweets, or a feeling that something has changed when you bite.
Combining these findings helps the dentist determine how much healthy tooth structure remains and which restorative approach makes sense.
What Is the Treatment Process Like?
The exact process depends on the tooth, the restoration being used, and the treatment plan.
First, the damaged or decayed portion of the tooth is removed. If an older restoration is present, it may also need to be removed so the dentist can see the condition of the tooth underneath.
The tooth is then shaped to receive the inlay or onlay. An impression or digital scan may be used to capture the shape of the prepared tooth and surrounding bite.
The restoration is created to fit that specific area. Once ready, it is positioned on the tooth, checked for proper fit and bite, and securely bonded into place.
Your dentist will also make sure the restored tooth works comfortably with the opposing teeth when you bite and chew.
What Do Dental Inlays and Onlays Look Like?
Modern restorative dentistry places considerable emphasis on both function and appearance. Depending on the material selected and where the tooth is located, an inlay or onlay can often be designed to blend naturally with the surrounding tooth.
This can make them particularly appealing when a patient wants to restore a damaged tooth without having an obvious restoration visible when speaking or smiling.
Appearance is not the only consideration, however. The material and design also need to withstand the forces generated during chewing.
Back teeth perform a significant amount of work, particularly the molars. Your dentist will consider the tooth’s location, your bite, the size of the restoration, and other factors when determining the appropriate restorative material and design.
Can an Inlay or Onlay Help a Cracked Tooth?
Possibly, depending on the location and extent of the crack.
Small cracks or weakened cusps may sometimes be reinforced with an onlay that covers the affected portion of the tooth. By restoring and protecting the weakened area, the dentist may be able to reduce stress on that portion during chewing.
However, cracks can vary significantly. Some affect only part of the outer tooth, while others extend deeper toward the pulp or root.
A deeper crack may require a crown, root canal therapy, extraction, or another form of treatment depending on the severity.
This is why a cracked tooth should be professionally evaluated rather than assuming that one particular restoration will solve the problem.
What Symptoms Could Mean a Tooth Needs Restorative Care?
Teeth that need restoration do not always produce obvious symptoms. Cavities and cracks can sometimes progress for a period of time before they become painful.
Symptoms worth discussing with your dentist include:
- Sensitivity to hot, cold, or sweets
- Pain when biting or chewing
- A visible crack or chip
- A rough or sharp tooth surface
- Food repeatedly becoming trapped in one area
- A loose or damaged filling
- Discomfort around an older restoration
- A visible dark area or hole in the tooth
These symptoms do not necessarily mean you need an inlay or onlay. They simply indicate that the tooth should be examined.
The earlier a problem is evaluated, the better your dentist can determine what treatment options remain available.
How Do You Care for an Inlay or Onlay?
Caring for an inlay or onlay is similar to caring for your natural teeth.
Brush thoroughly twice each day and clean between your teeth consistently. The edges where the restoration meets the natural tooth need to remain clean because the surrounding tooth structure can still develop decay.
Regular dental cleanings and exams are also important. Your dentist can check the restoration for signs of wear, changes in the bite, or problems developing around its margins.
Avoid using your teeth to open packages or chew objects such as ice and pens. These habits can place unnecessary force on natural teeth and dental restorations.
Patients who grind or clench may also want to discuss whether additional protection is appropriate, particularly if they have multiple restorations.
How Long Do Dental Inlays and Onlays Last?
There is no guaranteed lifespan for any dental restoration.
How long an inlay or onlay remains functional can depend on the material, the condition of the original tooth, oral hygiene, chewing habits, bite forces, diet, and whether the patient grinds or clenches.
The location of the restoration matters as well. Back teeth experience substantial pressure during normal chewing.
Routine dental appointments allow your dentist to monitor the restoration over time. If an edge becomes damaged, the bite changes, or decay develops nearby, addressing the concern earlier may help prevent more extensive damage to the tooth.
Patients should contact their dentist if an existing restoration begins feeling loose, painful, unusually sensitive, or different when biting.
Can a Tooth Need a Crown Later?
Yes. Dental needs can change over time.
A tooth restored with an inlay or onlay may eventually experience additional decay, wear, cracking, or damage. If enough tooth structure is lost later, a crown may become the more appropriate restoration.
That does not necessarily mean the original inlay or onlay was the wrong treatment. Restorative dentistry is based on the condition of the tooth at the time treatment is performed.
Whenever possible, dentists generally want to preserve healthy natural tooth structure while providing enough support for the tooth to function.
Regular preventive care can help identify changes around restorations before they become more extensive.
Restoring Damaged Teeth in the Greater Phoenix Area
Dental inlays and onlays provide another option between a traditional filling and a full dental crown. They may be useful when a tooth has moderate damage but still has enough healthy structure that complete crown coverage is not necessary.
Determining the appropriate restoration requires an examination. The amount of decay or damage, condition of existing dental work, strength of the remaining tooth, bite, and symptoms all influence the recommendation.
Dental Design Studios provides restorative dental care for patients throughout the Greater Phoenix area. If you have a damaged tooth, an older filling that is causing problems, or sensitivity when chewing, contact your local Dental Design Studios office to schedule an evaluation and learn about your treatment options.
Dental Care Across the Greater Phoenix Area
Dental Design Studios has nine convenient dental office locations throughout the Greater Phoenix area, making it easier for patients to access quality dental care close to home. Our offices serve patients in Avondale, Chandler, Glendale, Phoenix, Peoria, Gilbert, Scottsdale, and nearby communities.
Find a Dental Design Studios location near you:
- Apple Tree Dental Studio in Avondale
- Arizona Family Dental in Chandler
- 75th Ave Dental Studio in Glendale
- Happy Valley Dental Studio in Phoenix
- Hatcher Dental Studio in Phoenix
- Smile Dental Studio in Phoenix
- Thunderbird Dental Studio in Peoria
- Dental Design Studio in Gilbert
- Scottsdale Dental Studio in Scottsdale