What is the Difference Between a Filling and Inlays and Onlays?

You are probably familiar with dental filling since many people have at least one, but you might not be aware of the different types and how they’re used. Besides ordinary fillings, you can also restore your smile with an inlay or onlay. Read on to learn more about these types of restorations, and when your dentist may recommend them.

Types of Restorations

Thanks to advancements in technology, the dental restoration process has significantly improved both in materials and techniques. The type of restoration you choose will depend on several factors, such as the location and the severity of damage or decay. Generally, there are two types of dental restorations:

• Direct Restorations: These are restorations that dentists can entirely fabricate and complete within your mouth without requiring the use of a dental lab. In most cases, your dentist will complete this treatment within a single dental appointment, and you won’t need a temporary restoration. The most common direct restorations are dental fillings, typically made from composite resin or silver amalgam.
• Indirect Restorations: These are restorations manufactured in a lab or office milling machine before placing them on the affected tooth. Common examples include crowns, bridges, veneers, dentures, inlays, and onlays. When a dental lab is required, there are usually two dental appointments involved to complete your restoration.

What is a Dental Filling?

Dental fillings are designed to repair damaged or decayed teeth and eliminate any discomfort. Dental cavities result from harmful bacteria that accumulate due to the food particles that remain after every meal. These bacteria produce acids that combine with food particles and saliva to create a sticky film called plaque. Over time, plaque can gradually erode the protective enamel on your tooth and allow cavities to form.

Dental fillings are typically made of tooth-colored resin, porcelain, or silver combined with other materials. Sometimes, dentists combine two or more materials to strengthen the filling. Before placing a filling, your dentist will remove the decayed portions of the tooth using special instruments. The area is thoroughly cleaned before placing the filling material into the space left by the cavity.

Fillings effectively repair damage caused by decay, and composite (“white”) fillings can also restore the esthetic appearance of your teeth and give you a more confident smile.

What are Onlays & Inlays?

An inlay is a pre-made restoration designed to fit precisely within the chewing surface of a damaged or decayed tooth, almost like a puzzle piece. Inlays can repair the chewing surface of a back tooth and larger cavities in situations where a conventional filling wouldn’t be sturdy enough. These chewing surfaces can develop cavities quickly since they contain deep fissures that can trap plaque and bacteria.

With an inlay, your dentist will carefully prepare the tooth before taking a precise impression to be sent to a dental laboratory. Your custom inlay is then handcrafted from either porcelain or gold.

In some cases, your dentist may be able to make a porcelain inlay using advanced CAD/CAM technology while you wait. The final restoration can look amazing and eliminate the need to have a temporary filling while a specialist fabricates your inlay.

An onlay is very similar to an inlay but is a little larger. Dentists often use onlays to repair a cavity right at the center of your tooth’s chewing surface and on one or more of your tooth cusps (the raised areas on your tooth). Like inlays, onlays can be made either in a dental laboratory or on-site with a CAD/CAM-based milling machine.

Here are some key benefits of inlays and onlays over traditional fillings:

• Both protect your teeth and rejuvenate your smile
• Provide a natural white that blends seamlessly with the surrounding enamel
• Creates a highly durable covering of composite or porcelain that is resistant to staining
• Restores severely damaged teeth and prevents further damage, inflammation, or infection
• Strengthens a tooth by up to 75%
• Advanced materials won’t expand while in place

Choosing the Right Restoration

Whichever dental restoration you choose, it is always important to seek the guidance of a professional. Your insurance coverage can also affect your decision since some plans do not cover cosmetic restorations. Your dentist will advise you on the right restoration to choose based on expert diagnosis, risk assessment, and a physical exam to evaluate your remaining tooth structure. He or she will also consider other related issues such as finances, insurance, and time.

Have you ever needed to decide between a filling, inlay, or onlay? Share your thoughts and experience in the comments below!