Dental inlays and onlays present a superior alternative to “direct” amalgam or composite fillings for restoring teeth that have suffered some damage, but not enough to necessitate a full crown. Unlike direct fillings, such as dental amalgam and composite fillings, which are applied immediately after the removal of decay or damage and tooth preparation, inlays and onlays are considered “indirect” fillings. This implies that they are manufactured outside of the mouth before final bonding or cementation.
Traditionally, many inlays and onlays were crafted from gold, but modern dental inlays and onlays are typically custom-made from the finest dental porcelain or composite resins. These materials not only offer a precise color match to the natural tooth, resulting in an aesthetically pleasing outcome, but they also possess several distinct advantages. Compared to other types of fillings, inlays and onlays exhibit greater durability, preserve more underlying tooth structure, and even reinforce the tooth, enabling it to withstand 50 to 75 percent more chewing forces.
The main difference between inlays and onlays lies in the extent of tooth structure coverage. An inlay is created when the replacement of tooth structure does not require covering any cusp tips. Conversely, if the damage from decay or injury is more extensive and involves the chewing surface of the tooth, including one or more cusp tips, an onlay is necessary. Both inlays and onlays are fabricated based on detailed specifications derived from an impression of the prepared tooth. The final inlay or onlay is then custom-made either by a dental laboratory or through an in-office same day system.