What Are Inlays and Onlays? A Complete Guide to These Tooth-Saving Restorations

When a tooth is damaged by decay or minor fractures, dentists no longer rely only on traditional fillings or crowns. Modern dentistry offers inlays and onlays, conservative and long-lasting restorations that repair teeth while preserving their natural structure.

In this blog, we’ll explain what inlays and onlays are, how they work, their benefits, differences, procedure, cost, and who needs them—everything you need to know before choosing the right dental treatment.

What Are Inlays and Onlays?

Inlays and onlays are custom-made dental restorations used to repair teeth with mild to moderate damage. They are often referred to as partial crowns because they cover more area than fillings but less than full crowns.

These restorations are crafted outside the mouth (in a dental lab or using digital CAD/CAM technology) and then bonded securely to the tooth.

What Is a Dental Inlay?

A dental inlay fits inside the grooves (cusps) of the tooth, without covering the chewing surface.

Inlays are used when:

• Tooth decay or damage is limited
• The tooth structure is still strong
• A filling would be too weak, but a crown isn’t necessary

Inlays provide a precise fit and restore the tooth’s strength and shape naturally.

What Is a Dental Onlay?

A dental onlay extends further than an inlay and covers one or more cusps of the tooth.

Onlays are ideal when:

• The chewing surface is damaged
• A tooth has cracks or large cavities
• You want to avoid a full dental crown

Onlays are often called “partial crowns” because they offer broader coverage while preserving healthy tooth enamel.

Difference Between Inlays and Onlays

Feature	Inlays	Onlays
Coverage	Inside tooth grooves	Covers one or more cusps
Tooth Structure	More preserved	Slightly more coverage
Strength	Stronger than fillings	Nearly as strong as crowns
Best for	Small to medium cavities	Larger damage without full crown

Materials Used for Inlays and Onlays

Dentists customize inlays and onlays using durable and aesthetic materials such as:

• Porcelain or Ceramic – Natural-looking and stain-resistant
• Composite Resin – Cost-effective and tooth-colored
• Gold Alloy – Extremely durable (less common today)

Porcelain inlays and onlays are the most popular choice due to their strength, aesthetics, and longevity.

Inlay and Onlay Procedure: Step-by-Step

1. Tooth Preparation

The dentist removes decay or damaged portions of the tooth.

2. Impression or Digital Scan

An impression or 3D scan is taken to create a custom-fit restoration.

3. Temporary Restoration

A temporary filling may be placed until the final restoration is ready.

4. Placement & Bonding

The inlay or onlay is permanently bonded to the tooth and polished for a natural finish.

With same-day CAD/CAM dentistry, some clinics can complete the procedure in a single visit.

Benefits of Inlays and Onlays

• ✔ Preserve natural tooth structure
• ✔ Stronger and longer-lasting than fillings
• ✔ Excellent fit and comfort
• ✔ Natural tooth appearance
• ✔ Resistant to staining and wear
• ✔ Reduce risk of future decay

With proper care, inlays and onlays can last 10–30 years.

Inlays and Onlays vs Fillings and Crowns

Inlays & Onlays vs Fillings

• Stronger and more durable
• Less likely to crack or shrink
• Better fit for moderate damage

Inlays & Onlays vs Crowns

• Preserve more natural enamel
• Less invasive
• Ideal when full coverage isn’t required

Who Is a Good Candidate for Inlays and Onlays?

You may be a good candidate if you:

• Have moderate tooth decay or cracks
• Want a conservative alternative to crowns
• Need a long-lasting restoration
• Prefer natural-looking dental solutions

Your dentist will assess your tooth condition to determine the best option.

Cost of Inlays and Onlays

The cost varies based on:

• Material used
• Tooth location
• Clinic technology
• Dentist’s expertise

On average, inlays and onlays cost more than fillings but less than crowns, making them a cost-effective long-term solution.

How to Care for Inlays and Onlays

• Brush twice daily with fluoride toothpaste
• Floss regularly
• Avoid chewing hard objects
• Visit your dentist every 6 months

Proper oral hygiene helps extend their lifespan significantly.

Are Inlays and Onlays Worth It?

Yes. Inlays and onlays offer the perfect balance between durability, aesthetics, and tooth preservation. They are an excellent option for patients who want a strong, natural-looking restoration without removing too much healthy tooth structure.

Final Thoughts

Inlays and onlays are advanced dental restorations that provide strength, beauty, and longevity while protecting your natural teeth. If you’re dealing with tooth decay or damage and want a conservative solution, talk to your dentist about whether inlays or onlays are right for you.