To repair damage to the tooth’s biting surface, rather than using a simple filling, or a crown, a dentist will often use an inlay, or an onlay. Inlays and onlays can be made from porcelain, gold, or composite or ceramic resin, although porcelain is now becoming the material of choice because of its strength and potential to match the natural color of your tooth.
An inlay is similar to a filling and lies inside the cusp tips of the tooth. They are custom-made to fit the prepared cavity and are then cemented into place. An onlay is a more extensive reconstruction that covers one or more cusps of a tooth. Onlays are indicated in situations where a substantial reconstruction is required. However, more of the tooth structure can be conserved compared to the placement of a crown.
Inlays and onlays are applied in two dental visits. At the first visit, the old filling, or decay, is removed, and the tooth is prepared for the inlay / onlay. The dentist will then make an impression of the tooth, and send this impression to a dental laboratory. This impression will be used by the laboratory to construct a custom-made porcelain, or gold inlay / onlay. At this time the dentist will place a temporary sealant on your tooth and schedule a second appointment.
At the second visit, the temporary sealant is removed. Your dentist will then ensure that the inlay / onlay fits properly in the tooth and does not interfere with your bite. The inlay / onlay is then bonded into the tooth with a strong bonding resin, and polished smooth.
TYPES OF DENTAL INLAYS AND DENTAL ONLAYS
There are two types of dental inlays and onlays:
Tooth-Colored Inlays and Onlays
Several types of tooth-colored inlays and onlays have been developed primarily for use in larger defects in back teeth. These are used in place of a crown (cap) or filling (restoration). They are made of porcelain, other ceramics, or resin (plastic). These materials are made in a laboratory and are cemented into place using a liquid plastic form of cement. Two appointments are required for their completion. These are beautiful restorations, matching tooth structure nearly exactly, but they have not been used long enough for optimal research knowledge about their long-term characteristics.
Gold Inlays and Onlays
For nearly a century, cast gold inlays and onlays have been regarded by many dentists as the best, longest-lasting method to repair teeth. Inlays fit within the biting surface of the tooth, whereas onlays cover the top of the biting surface. Many of these restorations serve for most of a patient’s lifetime. However, they are difficult to accomplish, expensive, and highly demanding of the dentist’s skill.
THE PROCEDURE OF DENTAL INLAYS AND DENTAL ONLAYS
Two appointments of approximately one to two hours per tooth.
ADVANTAGES & DISADVANTAGE OF DENTAL INLAYS AND DENTAL ONLAYS
Avoid biting hard objects in order not to fracture the porcelain. Normal brushing and flossing. Use fluoride mouth rinse and toothpaste as prescribed by your dentist. Same dietary restriction (as above) for the longest restorative life.
Tooth sensitivity, short or long term, may be present in a few of these restorations. If tooth sensitivity persists, endodontics (root canal therapy) may be necessary, but this is infrequent. Some tooth-colored restorations break during service because they are not as strong as those made of metal. If breakage occurs, the restoration can be remade. Because these restorations have not been used as long as metallic restorations for back teeth, knowledge about long-term service is not complete.
For back teeth, metallic restorations are the major alternatives. Silver amalgam and cast gold restorations are strong, acceptable alternatives but are not as pleasing in appearance.
RESULT OF TREATMENT
Porcelain inlays/onlays can successfully achieve both esthetic and functional results in restoring discolored or metal posterior teeth. More conservative than full crown.