Inlay vs Onlay

Inlay vs Onlay: Understanding the Differences and Making the Right Choice

When it comes to dental restorations, have a number of options. Two popular choices for restoring a damaged or decayed tooth are inlays and onlays. These might sound similar, but they offer distinct advantages and disadvantages. Making the right choice between them is crucial for your dental health, and we’re here to break it all down for you.

What are Inlays?

A dental inlay is a type of dental filling that snugly fits into a decayed or damaged area within the chewing surface of your tooth. If the dental issue you’re facing is confined to that area, inlays are a viable option.


  • Less Invasive: Regular fillings require drilling away a good amount of tooth structure, even some parts that are healthy, to create space for the filling. Inlays, however, are less invasive and designed to fit precisely, which means you get to keep more of your natural tooth. Less tooth removal also translates to a quicker recovery time post-procedure.
  • Aesthetic Appeal: They are usually made from porcelain or composite materials that closely match the color of your teeth. Unlike metal fillings that are easy to spot, the composite resin of inlays blend in, making it almost impossible to tell you’ve had dental work done.


  • Limited Coverage: Inlays are perfect for small-to-medium-sized cavities or minor fractures but anything more extensive may need a different type of dental procedure. For larger decays that cross multiple cusps or involve the sides of your teeth, you might have to look into other options like onlays or dental crowns.
  • Cost: High quality often comes with a price, and inlays are no exception. Porcelain inlays tend to be pricier than standard amalgam or composite fillings. That said, the durability and aesthetic benefits they offer often justify the higher cost for many people.

What are Onlays?

While inlays are confined to the cusps of the tooth, onlays have a broader range, covering one or more cusps and even extending down the sides. They are a good compromise between inlays and a full-on dental crown; they offer a greater degree of coverage than inlays for those larger, trickier issues, without needing a full crown.


  • Extensive Coverage: Onlays are the go-to choice for larger areas of decay or fractures that are too extensive for inlays but maybe not dire enough to require a full dental crown.
  • Durability: Onlays are built to last. Made from materials like porcelain, resin, or even gold, they’re robust and long-lasting. Many people find that their onlays outlive traditional fillings, which means fewer visits to the dentist for replacements. Over time, this could actually be a cost-saving feature.


  • More Expensive: Quality and coverage often come with a bigger price tag, and onlays are no exception. However, keep in mind that their durability and extensive coverage might make them more cost-effective in the long run.
  • Longer Procedure Time: Preparing a tooth for an onlay is a bit more complex and, as a result, takes more time. It usually requires two appointments. In the first visit, your dentist prepares the tooth and takes impressions. Then, the onlay is custom-made in a lab. In the second visit, the onlay is fitted and bonded to your tooth.

When are Inlays or Onlays Needed?

If you have damaged teeth due to poor oral health or an accident, you likely need some sort of dental restoration. Generally, inlays and onlays come into play when you’ve moved past the need for a basic filling but don’t quite need a full dental crown. Here are some specific scenarios where these dental treatments could be beneficial.


  • Moderate Tooth Decay: If the cavity on your tooth isn’t too large and doesn’t affect the biting surface, dental inlays could be a great fix.
  • Small Fractures: For minor fractures that haven’t damaged the overall structure of the tooth, an inlay can be a solid choice.
  • Worn Down Teeth: If you have teeth that are worn down due to issues like teeth grinding but the natural tooth structure isn’t severely damaged, you may benefit from an inlay.


  • Large Cavities: When decay has spread to multiple cusps but hasn’t compromised the entire tooth, a dental onlay can be a good restorative option.
  • Major Fractures: If a tooth is fractured in such a way that an inlay won’t provide enough support, an onlay can cover the entire surface of the tooth and offer better structural integrity.
  • Replacing Old Fillings: In some cases, old or damaged fillings can be replaced with onlays. This is especially true for larger fillings that have failed or are beginning to fail.
  • Protect Weak Areas: If parts of your tooth are particularly weak and prone to fracture, an onlay procedure can provide additional support without requiring a full crown.

 What is the main difference between inlays and onlays?

The main difference between inlays and onlays lies in the area of the tooth they cover and the extent of damage they’re designed to repair. Simply put, inlays are used for more localized issues—think small to moderate-sized cavities or minor fractures that are contained within the cusps (the biting surface) of your tooth. Onlays, however, are the heavy lifters of dental restorations. They’re used when the damage is more extensive, covering one or more cusps and even extending down the sides of the tooth.

How Do I Know If I Need an Inlay or Onlay?

If you’ve experienced dental decay, inlays and onlays could be excellent dental restoration options for you. The best way to determine if you need an inlay or an onlay is to contact our dental professionals for a consultation. They’ll assess the extent of the dental damage, the structural integrity of the tooth, and your overall oral health to help you decide which type of restoration is best for you.

We can also help you navigate the process of using your dental insurance to pay for your procedure and give you oral hygiene tips for preserving your restored teeth in the future.

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