Onlay vs Crown

12 June 2026

Onlay vs Crown: Which One Is Right for You?

If your dentist has told you that you need a tooth onlay or a crown, you may be confused as to the differences between these two dental restorations, and why your dentist prefers one over another.

At Pearl Dental Clinic, we provide both onlays and crowns, including same day onlays & crowns using CEREC technology. Below are some of the things that you need to know to make informed decisions regarding your treatment options.

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What Is a Dental Onlay?

An onlay is a kind of restoration that covers the occlusal surface of one or more cusps (the raised points on the biting surface) of the tooth. Onlays are considered restorations that lie somewhere in between fillings and crowns. They are recommended when the extent of the damage does not allow the placement of a normal filling because of the tooth being too weak to support it but still in a healthy condition and thus does not require full coverage crown.

They can be constructed from ceramics, zirconia, or composite and made individually to ensure that they are tailored to the tooth. Since they only cover the damaged part of the tooth, they retain more of the original tooth structure.

What Is a Dental Crown?

A crown will fit around all of your natural tooth surface, covering the entire tooth. It will mostly be prescribed in case there is excessive damage to the natural tooth, it had a root canal treatment, or there is almost no sound natural tooth substance.

There are many crown materials available for dentists to choose from, such as ceramic, zirconia, porcelain-fused-to-metal, and gold. Our dentists will recommend which type would suit you best based on the tooth location and requirements for durability.

So What’s the Main Difference?

It really comes down to how much of the tooth needs to be covered.

An onlay is the more conservative option. It only covers the area that’s damaged, so less of the tooth needs to be shaved down during preparation. That means more of your natural tooth is preserved, which is a good thing.

A crown is the better choice when the damage is more extensive. If a large portion of the tooth is cracked, decayed, or weakened, a crown wraps around the whole thing and gives it full protection.

Here’s a quick comparison:

	Onlay	Crown
Coverage	Partial (one or more cusps)	Full (entire tooth)
Tooth preparation	Less shaving needed	More shaving needed
Best for	Moderate damage, large cavities	Heavy damage, root treated teeth
Preserves tooth structure	More	Less
Strength	Strong	Very strong
Materials	Ceramic, zirconia, composite	Ceramic, zirconia, gold, porcelain bonded to metal

When Would You Need an Onlay?

Our dentists may recommend getting an onlay for:

A large cavity that exceeds the dimensions suitable for a regular filling
When part of your tooth is broken, yet the tooth itself is intact
For a more durable alternative to a composite filling as onlays have a lot more strength than fillings
As a procedure that requires fewer changes to the natural tooth structure

An onlay provides extra strength to weak tooth cusp areas through covering. It can be very helpful in situations when your teeth have already had large fillings before and are at risk of fracturing.

When Would You Need a Crown?

A crown is usually the right call when:

Your tooth has a large fracture or has broken significantly
You’ve had root canal treatment and the tooth needs full protection
The tooth has been heavily filled before and there isn’t enough healthy structure left for an onlay
You grind your teeth and need something that can handle the extra pressure

In general, but especially after a root canal treatment, it is very crucial that you place a crown or an onlay with cuspal protection. The reason for this is that back teeth which have undergone root canal therapy are six times more likely to fracture if they are not covered with a crown.

Same Day Onlays and Crowns with CEREC

One of the advantages patients value the most about undergoing treatment in our clinic through the placement of an onlay or crown is the ability to complete this procedure in one visit.

The process of planning, designing, and fabricating your restoration is conducted using state-of-the-art technology known as CEREC restorations. We take a digital scan of your tooth and create the restoration virtually. Then we simply mill your restoration directly out of high quality composite or ceramic during your visit, which usually takes about two hours.

This way there’s no need to worry about having to wear a temporary crown for two weeks and return to the clinic for another appointment.

How Do You Look After an Onlay or Crown?

Caring for either is actually quite simple:

Brush two times daily using a fluoride toothpaste
Interdental brushing or flossing daily, especially at the borders of the restoration
Avoid eating or biting down on any hard objects such as pens or ice
Maintain excellent dental hygiene at home
Check-ups and periodic visits to our dental hygienist

Crowns are expected to last for ten to fifteen years under good maintenance, and onlays could potentially last similar length of time.

Book Your Consultation at Pearl Dental Clinic

Not sure if your tooth needs a veneer or crown? Don’t worry; it is common, and this is precisely what our dentists are here to sort out for you. Each and every tooth is unique, and depending on its condition, we will be able to determine which solution suits you best.

At Pearl Dental Clinic, we offer both treatments with same day CEREC options available, so you could have your tooth restored in just one visit. You can get to know our dental team and explore our patient reviews to see why patients have trusted us with their smiles since 2007.

To get started, call us on 0208 059 4085, send us a WhatsApp message, or book your consultation online at a time that suits you. Whether it’s an onlay or a crown, we’ll make sure you get the right treatment for your tooth.

Call us today on 020 8547 9997

Whatever you need, our friendly team is looking forward to hearing from you.

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