The types of these bridges tend to disappear mainly for aesthetic reasons, as today we have much more modern materials, biocompatible and, above all, with better aesthetic results. The only reasons why they can be used today are their lower cost and the lack of space that does not allow for the construction of aesthetic restorations requiring greater cuts in dental tissues.
In the case of purely metallic bridges, their use is limited only to mouths which due to limited space and short teeth the cutting of the dental tissues is required to be minimal. Their placement is therefore limited to posterior teeth. Metallocrylic bridges on the other hand have the disadvantage that the acrylic with time erodes, the color does not remain stable and gradually releases a particular taste in the mouth. The bond between the metal and the acrylic is not a chemical but purely mechanical, meaning there is no fixed bond between the metal and the acrylic, and it is sometimes worn out and leaves leaving the metal frame exposed. Because of its rapid abrasion the acrylic is placed only externally, covering the buccal surface of the metal skeleton.