Dental Inlays vs Fillings: Key Differences

Two women are smiling confidently after receiving dental inlays treatments instead of fillings

Tooth decay can strike anyone, turning what was once a radiant smile into a source of discomfort and self-consciousness. For many, the immediate solution that comes to mind is the traditional filling. However, advances in dental technology have provided alternatives that offer superior teeth restoration. Dental inlays present a modern, custom-tailored solution, offering precision, durability, and a natural appearance. Learn about the subtle and significant differences between these two dental solutions, helping you make an informed decision for your oral health.

What Is the Difference Between Dental Inlays, Onlays and Fillings?

Understanding the differences between dental inlays, onlays, and fillings is essential for anyone exploring restorative dental options. Dental inlays and onlays are custom-made solutions designed to address tooth decay or damage that is too extensive for a traditional filling but not severe enough to necessitate a crown.

Dentlay Inlays & Onlays

An inlay fits within the contours of a tooth’s biting surface, specifically within the cusps, providing a strong, precise, and aesthetically pleasing repair. An onlay, also a tailored restoration, extends over one or more of the tooth’s cusps, offering extended coverage and reinforcement for larger areas of damage.

Dental Fillings

In contrast, fillings were the standard treatment for smaller cavities and tooth decay. The material is applied directly and shaped in the mouth during the dental visit, making it a quick and efficient process.


While both inlays/onlays and fillings aim to restore a tooth’s structure and integrity, they vary in application, materials used, and how they are crafted. Inlays and onlays are made in a dental lab, or on the same day with CEREC (a method for creating dental restorations at our office) and then bonded to the tooth, providing a durable and precise fit that can enhance the tooth’s strength. Custom-fitted dental restorations generally offer a higher level of durability and aesthetic finish compared to fillings.


Read more: What You Need To Know About Dental Bonding

The Advantages of Dental Inlays & Overlays vs. Traditional Fillings

Dental inlays and onlays made from high-quality lithium disilicate materials are superior to standard fillings in several ways. They offer superior aesthetics and enhanced durability, lasting longer due to their resilient composition.


Inlays and onlays are conservative in tooth restoration; they require the removal of less healthy tooth structure than traditional crowns or fillings (required for larger cavities), thereby preserving more of the natural tooth. This aspect is crucial for maintaining the integrity of the tooth over time.


The precise craftsmanship of inlays and onlays allows for a perfect fit tailored to the unique contours of each tooth. This custom fitting not only ensures optimal comfort and stability but also provides a tight seal against the ingress of bacteria, significantly reducing the risk of future decay.


Lastly, inlays and onlays facilitate easy maintenance, integrating seamlessly with regular oral hygiene practices. Their design and materials make them simpler to clean than traditional fillings, which can sometimes have crevices that accumulate plaque and tartar. 

Inlays and onlays are custom dental restorations for moderate tooth decay, offering a more robust, aesthetic solution than traditional fillings. Inlays fit within the tooth’s cusps, while onlays cover more extensive tooth decay. They last longer, require less removal of the tooth structure than crowns, and are made from durable materials like e.max, enhancing tooth strength and reducing decay risk compared to standard fillings

Dental Inlay Procedure

  1. Conduct a thorough examination of the affected tooth.
  2. Utilise an iTero scanner to produce a precise digital impression, foregoing traditional impression techniques.
  3. Fabricate the inlay or onlay in-house using a CEREC CAD-CAM milling unit, usually completed within 15 minutes or less.
  4. Accurately position the inlay within the tooth cavity.
  5. Or carefully fit the onlay onto the tooth’s surface, bolstering and reinstating the tooth’s original form.
  6. Bond the inlay or onlay to the tooth to ensure a lasting and comfortable fit.

Traditional Filling Procedure

  1. Conduct an initial consultation to inspect the teeth and determine the suitability of a dental filling for minor fractures and decay.
  2. Use a dental probe, along with an X-ray, to locate and assess the extent of tooth decay.
  3. Choose the appropriate filling material, with porcelain as an option for its durability and aesthetic compatibility.
  4. Administer a local anaesthetic to numb the area around the affected tooth for patient comfort.
  5. Prepare the decayed or damaged tooth and surrounding area using a dental handpiece or laser to remove damaged parts. Cleanse the prepared area to eliminate any bacteria or debris.
  6. Apply composite filling material to fill the cavity, ensuring it conforms to the tooth’s natural shape.
  7. Place adhesives followed by the compositefilling material, then harden it using a special bonding light.
  8. Polish the filled tooth to achieve a smooth, finished surface that matches the rest of the teeth.

Inlay procedures use digital impressions and in-house milling to fit with durable materials like E-max precisely, strengthening teeth with minimal structure removal. Traditional fillings are directly shaped and hardened in the mouth, offering less reinforcement.

Why We Use The E-max and LiSi Material For Dental Inlays & Overlays

The Emax and Lisis substance, a lithium disilicate ceramic variant, boasts resistance to stains, chips, and fractures. Contrary to conventional fillings, which can diminish the natural tooth’s strength by as much as 50%, porcelain inlays and onlays utilise a high-strength material that adheres directly to the tooth, reinforcing it by as much as 75%.

Do Inlays Last Longer Than Fillings?

Inlays are renowned for their durability, typically outlasting traditional fillings with a lifespan ranging from 10 to 12 years and potentially beyond, with meticulous care. The longevity of inlays and overlays hinges on factors such as the material choice, their placement in the mouth, and the patient’s commitment to oral hygiene.

Final Thoughts On Dental Inlays vs. Fillings

Dental inlays and onlays stand out as modern, custom-crafted alternatives to traditional fillings, providing not only a precision fit but also enhanced aesthetic and structural benefits. Made from resilient E-max and LiSi material, these restorations reinforce the tooth significantly more than standard fillings and promise an extended lifespan of up to 12 years or more with proper care. They preserve the tooth’s natural structure and are particularly suited for cases where decay or damage is too advanced for a filling yet not severe enough to require a crown. In the spectrum of dental restorative options, inlays and onlays represent a superior blend of technology, durability, and design, making them a wise choice for long-term oral health and functionality.


Ready to embark on a path to a healthier smile? Let the dedicated team at OptiSmile assist. Book your appointment with us today and embrace a brighter, stronger smile.

Disclaimer: The information and advice in this blog post are intended for general informational purposes only and should not be considered a substitute for professional dental advice, diagnosis, or treatment. We are not responsible for any outcomes or decisions based on the information provided here.

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Dr. Clifford Yudelman

Founder & Principal Dentist

As a globally recognised restorative and cosmetic dentistry expert, Clifford brings over 40 years of experience across four continents. A 1983 Bachelor of Dental Science graduate from the University of Witwatersrand, his career has spanned private practices in London, San Diego, Perth, and Cape Town. Currently the founder and principal dentist at OptiSmile, he is celebrated for transforming dental visits into positive experiences and fostering patient confidence through superior dental health, with a commitment to the latest dental technology for improved patient outcomes.

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