The Inlay is a type of restoration is performed inside the mouth in the posterior or anterior sector. It consists of a coating whose function is to preserve the healthy structure that remains of a tooth. The tooth is cemented to replace the structure lost by decay, fracture or wear. They are performed in a laboratory using working models from the patient’s mouth.
How to prepare a dental inlay
Preparation for a dental inlay follows a pattern common to any type of encrustation. They are designed with divergent walls towards the outer walls of the cavity. The floors are left flat to make the restoration support stable. Finally, the angles are rounded to increase the resistance of the tooth to repair. The practice of grooves or bevels is completely omitted and a termination with amplitude and chamfer is sought (according to the desired dental aesthetic). Retentive spaces remaining in the cavity walls are filled with the glass ionomer.
Glass ionomer in dental encrustation
The glass ionomer modified with nano-charged resin (on the right side, rated as 2 occlusally and 1 gingival) and the high viscosity glass ionomer cement (on the left side; rated as 0 for occlusal and gingival) Class V cavities are applied to the same tooth. Next, an impression of the cavity is made by addition silicones or poly-ethers. For cases of dental inlays that are performed by dental CADCAM procedure, an optical/digital impression is made. This is carried out by means of a device designed to obtain an image of the cavity in the monitor. Using that image, you start designing the restoration. As a next step, a robotic process carves the embedding on a block of prepared material in a few minutes. The cavity is protected by a temporary seal while preparing and cementing the inlay. This type of temporary restoration is made with the same criteria as composite inlays. Once the laboratory preparation of the restoration is finished, it is tested in the mouth after removing the provisional seal. The cemented porcelain inlay is practically the same as that of composite. The difference lies in the conditioning of the surface of the dental porcelain. The porcelain inlay is treated with hydrofluoric acid or fluorinated ammonium before cementation. Next, the surface is silanized. After adding the embedding on the cavity, the excess cement is removed. Then, it is polymerized with halogen light according to conventional guidelines. Once the inlay is cemented, all occlusal contact is verified. It is retouched with fine-grained diamond strawberries. Then, it is polished with abrasive rubber suitable for the case and with polishing paste. In cast glass and apatite ceramics, color and characterization can be eliminated. This is done in cases where the restoration is “high” and it is necessary to remove material.
Dental inlays, on-lay and overlay
There are three types of dental inlays: inlays, on-lays and overlays. These aesthetic restorations are intended to repair endodontic posterior teeth or of great destruction by caries. Its use extends to the restoration of cracked or fractured posterior teeth. This, in cases where the destruction of the dental structure is not serious enough to need a dental crown. Inlay type inlay consists of one that does not cover any dental cusp. The onlay comes to cover at least one cusp, but without covering them all. Overlay is an inlay of full cusp covering. The techniques for its preparation are called direct, semi-direct and indirect. Direct technique is an intraoral process of a single appointment. It is indicated in restorations of preventive type and small and medium sizes. The semi-direct technique is a procedure that can be carried out intra or extra orally. Cemented restorations are made in the clinic. These can be applied in a long or two short appointments. It is suitable for medium or large size restorations. In the indirect technique the laboratory intervenes in the manufacturing process. It requires more than one appointment for its correct elaboration. It applies to large restorations.