Inlays and onlays are forms of indirect dental restorations used to repair damaged or decayed teeth. Unlike traditional fillings, which are placed directly into a cavity, inlays and onlays are custom-made in a dental laboratory and then bonded to the affected tooth. These restorations are more durable and aesthetic than regular fillings and help preserve more of the tooth's natural structure.

Difference Between Inlays and Onlays

Inlays: These are used to repair damage confined to the inner surface (the grooves) of the tooth. Inlays fit within the cusps of the tooth and are ideal for moderate decay or damage that doesn't affect the outer edges of the tooth.

Onlays: Larger restorations that extend over the cusps (the points on the top) of the tooth. Onlays are used when the damage is more extensive and involves part of the top surface and sides of the tooth.

When Are Inlays and Onlays Needed?

• Moderate to severe tooth decay: When a tooth has substantial decay but not enough to require a full crown.

• Broken or chipped teeth: If a tooth is damaged but still has healthy structure, an inlay or onlay can restore its function and shape.

• Cosmetic concerns: If a tooth is discolored or unsightly, an inlay or onlay made of porcelain or composite materials can restore its appearance.

• Tooth structure preservation: Inlays and onlays are ideal when restoring function without compromising the tooth’s integrity.

Inlay Procedure

Diagnosis and Preparation:

The dentist will examine the tooth, often using X-rays to assess the extent of the damage or decay. Local anesthesia is applied to numb the area.

Tooth Shaping:

The decayed or damaged part of the tooth is removed, and the remaining structure is shaped to accommodate the inlay.

Impression:

An impression of the prepared tooth is taken and sent to a dental lab to create a custom inlay that will fit precisely into the cavity.

Temporary Restoration:

While the inlay is being made (typically taking 1–2 weeks), a temporary filling is placed to protect the tooth.

Placement of the Permanent Inlay:

Once the inlay is ready, the dentist removes the temporary filling and checks the fit. If the inlay fits properly, it is bonded to the tooth using dental cement.

Onlay Procedure

The procedure for onlays is similar to inlays, but the preparation involves more shaping of the tooth surface since onlays cover a larger portion of the tooth.

Diagnosis and Preparation:

Like inlays, the dentist assesses the extent of damage and uses X-rays for a comprehensive diagnosis. Local anesthesia is used for numbing.

Tooth Shaping:

The damaged or decayed portion of the tooth is removed and shaped to accommodate the onlay. Since onlays cover more surface area than inlays, the preparation is slightly more involved.

Impression:

After the tooth is prepared, an impression is taken and sent to a dental lab to create the onlay.

Temporary Restoration:

A temporary restoration is placed on the tooth while the permanent onlay is being crafted.

Placement of the Permanent Onlay:

Once the onlay is ready, the dentist checks the fit and bonds it to the tooth using dental cement.

Materials Used for Inlays and Onlays

• Porcelain: The most commonly used material, porcelain inlays and onlays are highly aesthetic, durable, and stain-resistant. These are ideal for visible teeth, as they blend seamlessly with natural tooth color.

• Composite Resin: Tooth-colored and more affordable than porcelain, composite resin is a great option for those seeking a budget-friendly restoration. However, it may not be as long-lasting or durable as porcelain.

• Gold: Gold inlays and onlays are incredibly durable and offer excellent protection. They are typically used for back teeth, where aesthetics are less of a concern.

• Ceramic: Ceramic is similar to porcelain but may be slightly more wear-resistant, offering a good combination of aesthetics and durability.

Advantages of Inlays and Onlays

• Durability: Inlays and onlays are strong and can withstand the forces of chewing and biting. They are often more durable than traditional fillings.

• Aesthetic Appeal: Porcelain and composite inlays and onlays can be color-matched to blend with your natural teeth, making them an excellent choice for visible areas.

• Conservative Treatment: Inlays and onlays require less tooth reduction than crowns, preserving more of the natural tooth structure.

• Stain Resistance: Porcelain inlays and onlays are highly resistant to staining, maintaining their appearance over time.

Disadvantages of Inlays and Onlays

• Cost: Inlays and onlays tend to be more expensive than traditional fillings, especially if porcelain or ceramic is used.

• Time: The process typically requires two dental visits: one to prepare the tooth and take impressions, and a second to place the permanent restoration.

• Tooth Preparation: While less invasive than crowns, some tooth structure must be removed to accommodate inlays and onlays, which may not be ideal for every patient.

• Risk of Damage: Although durable, porcelain or ceramic inlays and onlays can chip or crack under heavy pressure, such as from teeth grinding (bruxism).

Inlays vs. Onlays: Which One Is Right for You?

Inlays are ideal for smaller areas of damage or decay, particularly within the grooves of the tooth. They work best when the tooth's outer edges are intact.

Onlays are better suited for larger restorations when a significant portion of the tooth’s surface, including the cusps, has been compromised. Your dentist will assess the size of the cavity, the tooth’s location, and your cosmetic preferences to recommend the best option.

Conclusion

Inlays and onlays are fantastic restorative options for patients who need more durable and aesthetic solutions than traditional fillings. They can restore the function, strength, and appearance of damaged teeth while preserving more of the natural tooth structure. While they require more preparation than a regular filling, inlays and onlays provide long-lasting, natural-looking results.

If you’re concerned about damaged or decayed teeth, talk to our dentists about whether inlays or onlays could be the right treatment for you.

Please, call for the consultation: (425) 430-2029