Onlays vs Crowns: Which Is Right for Your Tooth?

When your tooth is damaged, you want to fix it quickly. But should you get a crown or an onlay? Many Nashville patients ask this question.

Both options restore damaged teeth. But they work in different ways. One covers your whole tooth. The other covers only part of it.

At Dental Faith, we help patients choose the right treatment. This guide explains both options in simple terms. You’ll learn when each one works best and how dentists make the choice.

What Is a Dental Onlay? (Conservative Restoration)

An onlay is sometimes called a “partial crown.” It covers the damaged part of your tooth while leaving healthy tooth structure alone.

When Dentists Use Onlays

Onlays work well for moderate damage. Your tooth has some decay or a crack, but most of it is still healthy. Removing the entire top of your tooth would waste good tooth structure.

Think of it this way: if a dental filling is too small but a dental crown is too much, an onlay is just right.

What Onlays Are Made From

Most onlays use porcelain, ceramic, or composite resin. These materials match your tooth color. No one will notice you had work done.

Some dentists use gold for back teeth. Gold lasts longer but looks metallic.

What Makes Onlays Different

Onlays cover the cusps of your tooth. Cusps are the raised bumps on your chewing surface. The onlay fits over these bumps and bonds to your tooth.

This approach saves more of your natural tooth than a crown does.

Best For

• Moderate decay that’s too big for a filling
• Cracked cusps that need support
• Large old fillings that are breaking down
• Patients who want to keep as much natural tooth as possible

Pros

• Keeps more of your natural tooth
• Strong and durable
• Looks natural
• Costs less than a crown
• Less tooth removal needed

Cons

• Won’t work for severe damage
• Takes two visits to complete
• Can still crack if you grind your teeth
• Not strong enough for teeth with root canals

What Is a Dental Crown? (Full Tooth Coverage)

A crown covers your entire tooth above the gum line. People often call them “caps.”

Crowns wrap around your tooth like a helmet. They protect weak or broken tooth from further damage.

When Dentists Use Crowns

Your dentist will recommend a crown when your tooth is badly damaged. Maybe you have a large cavity. Or your tooth cracked in half. Perhaps you just had a root canal.

In these cases, your tooth doesn’t have enough structure left to support an onlay. It needs full coverage to survive.

What Crowns Are Made From

Crowns come in several materials:

• Porcelain: Looks most natural, great for front teeth
• Ceramic: Strong and tooth-colored
• Zirconia: Very strong, works well for back teeth
• Porcelain-fused-to-metal: Strong with a natural look

Your dentist will suggest the best material for your tooth location and bite strength.

How Crowns Protect Teeth

Crowns hold weak teeth together. After a root canal, your tooth becomes brittle. A crown prevents it from breaking.

For large cavities, a crown stops the tooth from splitting apart when you chew.

Best For

• Severe decay or large cavities
• Cracked or broken teeth
• Teeth after root canal treatment
• Very worn teeth from grinding
• Teeth that are too weak for onlays

Pros

• Strongest protection available
• Prevents further damage
• Restores full chewing ability
• Lasts many years with care
• Can save badly damaged teeth

Cons

• Costs more than onlays
• Requires removing more tooth structure
• Takes two visits (usually)
• May cause temporary sensitivity
• Needs replacement eventually

Learn more about our restorative dentistry services.

Onlay vs Crown: Key Differences

Here’s how these two treatments compare:

Amount of Tooth Removed

Onlays need less tooth removal. Your dentist removes only the damaged part. Healthy tooth structure stays in place.

Crowns require more removal. Your dentist must shape the entire tooth so the crown fits over it.

Strength and Protection

Crowns provide more protection. They cover and support your whole tooth. This makes them better for severe damage.

Onlays are strong but offer less coverage. They work well for moderate damage but can’t handle as much force as crowns.

Durability

Both last a long time with good care. Crowns typically last 10 to 15 years. Onlays last about the same, sometimes longer because they preserve more tooth.

Cost

Onlays cost less than crowns. You’re paying for less material and less tooth preparation.

Crowns cost more but provide more protection. For badly damaged teeth, the extra cost is worth it.

When Each Is Recommended

Your dentist chooses based on how much tooth structure remains. More healthy tooth? An onlay might work. Little tooth left? You need a crown.

When Dentists Recommend an Onlay

Your dentist will suggest an onlay in these situations:

Moderate Decay

You have a cavity that’s too large for a filling. But the tooth still has plenty of healthy structure around it.

An onlay removes the decay and covers the damaged area. The rest of your tooth stays natural.

Cracked Cusps

The pointy parts of your tooth (cusps) can crack from biting hard foods. Or from grinding your teeth at night.

An onlay covers these cusps and prevents the cracks from spreading.

Large Fillings Breaking Down

Old metal fillings can weaken your tooth. As they age, they may crack or leak.

Your dentist can replace them with onlays. This strengthens your tooth and looks better too.

Aesthetic Improvements

Some patients want to improve their smile without full crowns. Onlays can reshape and brighten teeth with less tooth removal.

Preserving Tooth Structure

If you’re young or want to keep your natural teeth as long as possible, onlays are ideal. They’re the most conservative option that still provides strength.

When Dentists Recommend a Crown

Your dentist will recommend a crown in these cases:

Extensive Decay

When a cavity affects most of your tooth, a crown is necessary. There’s not enough healthy tooth left to support an onlay.

The crown holds everything together and stops further decay.

Large Fractures

A crack that goes deep into your tooth needs a crown. The crown wraps around the tooth and keeps it from splitting apart.

Without a crown, the tooth will likely break and need removal.

After Root Canal Treatment

Root canals remove the nerve and blood supply from your tooth. This makes it brittle and dry.

A crown protects the tooth from breaking when you chew. Most teeth need crowns after root canals.

Severely Worn Teeth

Grinding your teeth wears them down over time. When they get too short or thin, crowns restore their height and strength.

This also helps your bite work correctly again.

Teeth With Weak Structure

Some teeth have large old fillings that take up most of the tooth. Others have thin walls that might break.

These teeth need the full protection of a crown.

Procedure Comparison (Step-by-Step)

Both treatments follow similar steps. Here’s what to expect:

First Visit

Your dentist numbs your tooth so you feel no pain. Then they remove decay and damaged tooth structure.

For an onlay, they shape only the damaged area. For a crown, they shape the entire tooth.

Next, they take an impression or digital scan of your tooth. This goes to a lab that makes your custom restoration.

Finally, they place a temporary onlay or crown. This protects your tooth while you wait.

Between Visits

The lab creates your permanent restoration. This takes one to two weeks. Some offices have labs on-site and can make it the same day.

Be gentle with your temporary restoration. Don’t chew hard foods on that side.

Second Visit

Your dentist removes the temporary restoration. They check the fit of your permanent one.

If it fits well, they cement it in place. You might feel slight pressure but no pain.

After it’s bonded, your dentist checks your bite. They make small adjustments so everything feels comfortable.

Same-Day Options

Some dental offices use CAD/CAM technology. This means they can design and make your restoration in one visit.

You skip the temporary and leave with your permanent restoration the same day.

How Much Do Onlays & Crowns Cost in Nashville?

Costs vary based on several factors. Here’s what affects the price:

Material Choice

Porcelain and ceramic cost more than metal. Gold costs the most. These materials look better and last longer.

Tooth Location

Front teeth need better aesthetics. This can increase cost. Back teeth need stronger materials for chewing.

Damage Level

More damage means more time in the dental chair. This affects the final cost.

Insurance Coverage

Most dental plans cover part of the cost. Many pay 50% for crowns and onlays. Check your benefits before treatment.

Typical Ranges

Onlays generally cost less than crowns. The difference can be a few hundred dollars.

Crowns provide more coverage and protection, which explains the higher cost.

Long-Term Value

Both treatments prevent bigger problems. A crown or onlay can save you from needing:

• Root canals
• Dental extractions
• Dental implants
• Dental Bridges

Fixing your tooth now costs less than replacing it later.

Which Option Lasts Longer? Durability Comparison

Both onlays and crowns are built to last. But several factors affect how long they hold up.

Typical Lifespan

Onlays last 10 to 15 years on average. Some last even longer with excellent care.

Crowns also last 10 to 15 years. Many patients get 20 years or more from their crowns.

Material Strength

Zirconia is the strongest option for both crowns and onlays. It rarely chips or breaks.

Porcelain looks great but can chip if you bite something very hard.

Gold is extremely durable. It wears down slowly and fits well over time.

Your Oral Hygiene

Good brushing and flossing make your restoration last longer. Plaque and bacteria can cause decay around the edges.

Regular dental cleanings catch problems early.

Bite Pressure

If you grind or clench your teeth, wear a night guard. Grinding puts extreme pressure on restorations and can crack them.

Back teeth handle more chewing force. This means they may need replacement sooner than front teeth.

What Shortens Lifespan

• Biting hard objects like ice or pens
• Nail biting
• Not wearing a night guard if you grind
• Skipping dental checkups
• Poor oral hygiene

Take care of your restoration and it will take care of you.

Onlays vs Crowns Comparison Table

Feature	Onlay	Crown
Coverage	Covers damaged part only	Covers entire tooth
Tooth Preservation	Saves more natural tooth	Requires more removal
Strength	Strong for moderate damage	Strongest protection
Best For	Medium cavities, cracked cusps	Severe damage, root canals
Durability	10-15+ years	10-15+ years
Aesthetics	Natural-looking	Natural-looking
Cost	Lower	Higher
Procedure Time	2 visits (or same-day)	2 visits (or same-day)

How to Know Whether You Need an Onlay or Crown

You can’t decide this on your own. Your dentist needs to examine your tooth.

Dental Examination

Your dentist checks how much healthy tooth remains. They look for cracks, decay, and weak spots.

They also test if your tooth hurts when you bite down.

X-rays and Imaging

X-rays show decay between teeth and under old fillings. They reveal cracks that aren’t visible on the surface.

Sometimes your dentist needs a 3D scan to see the full extent of damage.

Tooth Condition

Several factors help your dentist decide:

• How much tooth structure is left
• Where the damage is located
• Whether you’ve had a root canal
• How much force that tooth handles when chewing
• Your overall oral health

Bite and Sensitivity Issues

If your tooth hurts when you chew, it needs protection. Your dentist figures out if an onlay provides enough support or if you need a full crown.

Sensitivity to hot and cold might mean the nerve is affected. This could change the treatment plan.

Why You Can’t Self-Diagnose

What looks like a small cavity on the surface might be huge underneath. A tiny crack could go deep into your tooth root.

Only your dentist can see the full picture with exams and X-rays.

Check out our cosmetic dentistry options or book an appointment for an evaluation.

Frequently Asked Questions

Get the Right Treatment for Your Tooth

Unsure whether you need a crown or an onlay? Our Nashville dentists at Dental Faith will examine your tooth and recommend the safest, most conservative treatment.

We take the time to explain your options. You’ll understand why we suggest a specific treatment. We never push unnecessary procedures.

Our goal is to save your natural tooth structure whenever possible. But we also make sure your restoration lasts as long as possible.

Book an appointment today or contact Dental Faith to learn more about our restorative and cosmetic dentistry services.

Let’s protect your smile and keep your teeth healthy for years to come.