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Part 2 - The Inlay/Onlay Dilemma - How to Get Insurance Coverage

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The initial segment (Part 1) of this series explores the complexities surrounding inlays and onlays when seeking reimbursement through dental insurance. To summarize, both procedures often get "downgraded" by insurance providers to the level of fillings, leading to increased costs for your patients. The subsequent sections of this article are dedicated to exploring potential remedies for this issue.

The Inlay 

How to handle this challenge requires knowing how the different procedures relate to each other. An inlay is simple, as it does not cover any cusps. As a result, Inlays are almost always downgraded, therefore it is rare to ever receive reimbursement for anything more than a filling. The best solution in this scenario is to acknowledge the inevitable occurrence and either inform the patient about the anticipated costs in advance or explore alternative treatment possibilities.

The Onlay

Onlays have a wider range of coding possibilities. An onlay can cover anything from one to all cusps of a tooth. As a result, it has the potential of being considered under the definition of a “crown.” A crown has the more distinctive definition of covering all cusps of a tooth, or a ¾ crown of covering around 75% of the occlusal surface of the tooth. There is no coding distinction between where the margin exists for the restoration.

Let’s think back to high school geometry: A rectangle is a 4-sided shape with both parallel sides being equal length. A square is a 4-sided shape with all sides being equal length. Therefore, all squares are rectangles, but not all rectangles are squares.

Onlays and crowns share similar relationships to rectangles and squares. The crown would be the square with a more rigid definition, and the onlay would be the rectangle with a broader definition. So, all crowns (from a coding view) can be seen as onlays as well, but not all onlays can be seen as a crown.

Venn Diagrams can help visualize this as well:

As the diagram above shows, many onlays can be considered crowns or ¾ crowns by coding definitions. If you have an onlay that covers all the cusps of a tooth, that can also legitimately, by definition, be coded as a crown. If you have an onlay that covers most of the occlusal surface of a tooth, but not all, that could be coded as a ¾ crown. In both cases, the crowns would become covered services and therefore reimbursable by insurance both in and out of network resulting in less out of pocket costs for the patient.

If an onlay would fit the crown description (full occlusal coverage) it could then be reimbursed as a crown instead of a downgraded filling. As a filling, the patient might get $120 (80% of $150) reimbursement, but as a crown they would receive $400 (50% of $800) reimbursement, cutting their “out of pocket” cost tremendously.

Out of network, the patient might get $240 (80% of $300) reimbursement for an onlay, but as a crown they might receive upwards of $700 (50% of $1,400) reimbursement, cutting their “out of pocket” cost even more than in-network.

While there is no changing how insurance companies treat individual codes, there are occasionally ways to restructure how we are coding services to be able to provide better service to our patients. This must always be done within the context of the code description itself.

If you would like a detailed case breakdown on how to get crowns and other restorations covered, please check out this on-demand course: Understanding Insurance: Crowns, Bus, and Other Restorative Services

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by Dr. Travis Campbell

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