Inlays and onlays function just like fillings do – they fill in areas of tooth decay. In fact, in the dental world they are known as “indirect fillings.” Indirect, because the filling itself is made outside of the mouth and then bonded to the tooth that needs repair. Direct, traditional fillings are placed directly into a tooth once the decay is moved.

Keep reading to learn more about inlays and onlays, and how they differ from traditional fillings.

What Are Inlays and Onlays?

Inlays and onlays are the same type of filling – the only difference lies in where each one is placed in the tooth.

• An inlay fits completely inside a tooth, without affecting the surface or cusps.
• An onlay fits inside a tooth, but expands out to cover part of the surface or to replace a broken cusp.
• Inlays and onlays are made of gold, composite resin, or porcelain. Gold is the strongest material and best suited for the back molars, which bear the brunt of chewing force. Porcelain is recommended for the smile line, because it looks the most natural, color-wise. The durability of composite resin makes it a good choice for teeth grinders.

When Are Inlays and Onlays Used?

Inlays and onlays are used to repair mild to moderate decay, to fix cracks and fractures, and to replace old or broken fillings. When the affected tooth still has sufficient structure remaining, inlays and onlays can be used as conservative repairs in place of bigger and more extensive dental work. For example, if your tooth has damage that’s too deep for a filling, but not widespread enough for a crown, an inlay or onlay can be placed instead.

How Is An Inlay or Onlay Placed?

The process requires two dentist appointments. At the first appointment, your dentist will numb the affected area with anesthesia, drill out the tooth decay, and make an impression of the area that needs to be filled. The impression will be sent to a dental lab, where porcelain, resin, or gold will be molded into an inlay or onlay that fits the size of your tooth. In the meantime, your dentist will place a temporary filling to keep the affected area covered. You’ll return for a second appointment to have your inlay or onlay placed. The material will be sealed to your tooth by a process called bonding. Your dentist will perform final touch-ups and polishing to ensure the new inlay or onlay looks natural.

What Are the Benefits of Inlays and Onlays?

• The dentist will need to remove less natural tooth than it would take to place a crown. For a crown, the tooth is shaved down to fit under the crown structure. But for an inlay or onlay, the material is molded to fit inside the remaining tooth structure over the area of decay.
• Inlays and onlays strengthen teeth to bear more chewing and biting force. They also help preserve the surrounding tooth structure for a longer life. In contrast, metal fillings weaken teeth over time.
• Inlays and onlays are strong, durable, and long-lasting. They require no special care outside of your regular oral hygiene routine.
• The porcelain or resin matches the color of the surrounding teeth and looks natural.

If you are ready to discuss treatment options for a cracked, fractured, or decayed tooth, or a tooth that needs a replacement filling, contact Boyett Family Dentistry today.