Composite Inlays and Onlays: A Durable and Affordable Option

Last updated on November 6th, 2024

Composite Inlays and onlays, also known as partial crowns, are effective alternatives to traditional fillings and full crowns. If the cusps of a tooth are severely decayed, fillings may fail to cover the area, and crowns can be too invasive and costly. Made from different materials than crowns or fillings, inlays and onlays are practical, inexpensive, and durable solutions.

Inlays and onlays are usually made from gold, porcelain, or composite materials. In this article, we will be focusing on the composite inlays and onlays, only. Here, you will find the key points about composite inlays and onlays such as the indications, procedural steps, and aftercare routine. There is also a FAQ section at the end of the post where you can find answers to a few further questions regarding this dental treatment.

What are Composite Inlays and Onlays?

Composite inlays and onlays are dental bonding materials made from zirconia/silica and plastic materials. Similar to other dental restorations, the purpose of composite inlays and onlays is to restore the natural tooth affected by the cavity. 

This image provides a visual comparison of inlays and onlays. As you see in the image, Inlays fit within the cusps of the tooth, filling a smaller area, while onlays cover one or more cusps, offering more extensive coverage for larger cavities. Both options are designed to restore function and aesthetics, providing durable and natural-looking solutions for patients.

Patients are usually painfully aware of their dental problems and thus consider getting this treatment when they feel a toothache or tooth sensitivity or when they see visible damage to their teeth. Recently, more and more people are opting for composite inlays or onlays as a part of cosmetic dentistry to restore their beautiful smile, while at the same time getting rid of pain and sensitivity.

What Are the Benefits of Composite Inlays and Onlays?

Composite inlays come with the added benefit of, according to a review study published in The Journal of Conservational Dentistry in 2018:

• Reduced polymerization shrinkage
• Improved fracture resistance
• Improved wear resistance
• Better contouring of proximal surfaces
• Occlusal contacts
• Teeth Strength increase
• The teeth look fit, smooth, and natural
• Ease of cleaning teeth
• Teeth stability increase
• Prevents decay of the tooth for a long time
• Teeth lifespan increase

What is the Difference Between Composite Filling and Composite Inlay and Onlay?

Compared to dental fillings, composite inlays and onlays cover a larger area of the tooth, which conserves more of the existing natural tooth structure. Also, the color of composite inlays and onlays blends more naturally with the tooth as compared with dental fillings. However, the cost of this treatment tends to be higher than fillings. Additionally, the time required might be longer since dentists usually complete the inlay/onlay treatment in two separate appointments.

Composite inlays and onlays are also often compared to dental crowns. As you might already know, crowns cover the whole tooth, as this is a better option for those having no natural cusp on the tooth that can be filled. However, inlays/onlays are applied on the cusps of the tooth in varying shapes and quantities, which are measured by the impression taken from the patient’s tooth. As for price, crowns are usually a bit more expensive than composite inlays and onlays.

What Is the Procedure for Getting Composite Inlays and Onlays?

The procedural steps of composite inlays and onlays are similar to other inlay/onlay treatments where different materials are used. Here’s a breakdown of the most common steps dental professionals follow:

• During the first appointment, the dentist administers local anesthesia to numb the tooth.
• The dentist removes any caries and decayed portions of the tooth.
• Once the area is clear of decay, the dentist takes an impression of the tooth.
• A temporary inlay or onlay is placed, and a second appointment is scheduled.
• The composite inlay or onlay is custom-made in a laboratory. Some dental clinics have an in-house lab, enhancing the quality and efficiency of the work.
• At the second appointment, the temporary restoration is removed, and the permanent inlay/onlay is adhered to using strong adhesives.
• Finally, the dentist checks the alignment of the teeth to ensure a proper and comfortable bite.

The video provides an informative step-by-step guide on the procedure for getting composite inlays and onlays.

What Are the Advantages of Composite Inlays and Onlays Over Porcelain Inlays and Onlays?

• Conservative preparation: Composite inlays/onlays require less tooth structure to be removed than porcelain inlays/onlays, resulting in a more conservative tooth preparation.
• Ease of repair: In the event of damage, composite inlays/onlays can be easily repaired, whereas porcelain inlays/onlays may need to be completely replaced.
• Aesthetics: Composite inlays/onlays can be color-matched to natural teeth, resulting in a more aesthetic restoration compared to porcelain inlays/onlays.
• Lower cost: Composite inlays/onlays are generally less expensive than porcelain inlays/onlays.
• Bonding: Composite inlays/onlays can be bonded to the tooth structure, creating a strong and durable bond that can improve the overall strength of the tooth, while porcelain inlays/onlays require cementation. 
• According to a study published in the Journal of Conservative Dentistry in 2010, composites have a greater capacity to absorb compressive loading forces and reduce impact forces by 57% more than porcelain.
• Composite materials transfer masticatory forces considerably less than porcelain and porcelain-fused-to-metal restorations.
• Due to the similar composition of the luting cement and composites, the marginal adaptation of composites is better than that of ceramics.

What Are The Indications For Composite Inlays And Onlays?

The indications for having an inlay or an onlay are as follows according to a review study published in The Journal of Dental Health Oral Disorders & Therapy in 2015,

• The patient is seeking an excellent aesthetic result.
• The patient is practicing proper dental hygiene.
• The patient will not have any allergic reactions to the filling (amalgam)
• The patient is suffering from loss of hard tissue in their mouth.

How to Care For Your Composite Inlays And Onlays?

To prolong the lifespan of your composite restorations and maintain oral health, dentists strongly recommend the following care practices:

1. Regular Brushing: Brush your teeth twice a day with fluoride toothpaste to reduce plaque buildup and prevent decay around the inlay/onlay.
2. Daily Flossing: Flossing once a day is crucial to remove food particles and bacteria between teeth, which can lead to decay near the edges of the inlay or onlay.
3. Limit Staining Foods and Drinks: Be cautious with coffee, tea, red wine, and other staining substances, as they can discolor the exposed natural tooth structure around the composite material.
4. Routine Dental Check-ups: Schedule regular dental visits for professional cleanings and assessments to monitor the condition of the inlay/onlay and surrounding teeth.
5. Avoid Hard Foods: Avoid chewing on hard objects like ice or pens, as this can damage the composite material or place stress on the tooth structure.

By following these guidelines, patients can help ensure their composite inlays and onlays remain in good condition, contributing to a healthy, lasting smile.

What Is The Expected Longevity Of Composite Inlays And Onlays?

The long-term clinical results of composite inlays and onlays was a respectable 85% success rate (with only a 15% failure rate) at the end of a 9-year follow-up, according to a study published in The European Journal of Dentistry 2022. 

FAQs 

Here are the most common questions that people ask about composite inlays and onlays. 

Can I Convert My Amalgam Fillings To Composite Fillings?

Yes, dentists can remove your old amalgam fillings and replace it with inlays or onlays.

Can I Get An Onlay Instead Of A Crown? 

If a minor restoration is needed to fix the decayed cusps of a tooth, then a crown might be too excessive. Therefore, your dentist might advise you to get inlays or onlays.

Is It A Good Idea To Replace Amalgam Fillings With Inlays/Onlays?

Yes, it is. Amalgam fillings can expand and contract due to hot and cold drinks, which can lead to various problems.