Fixed retainers are a group of retainers that have one thing in common: they are bonded to the teeth. Most patients have heard of or seen the metal kind, which looks like a thin wire. A fixed retainer can also be made using a cast-metal technique, in the form of a metal strip 2–3 mm wide. Alternatively, a fibre splinting strip can be used, which is tooth-coloured and blends in with the teeth. Its main advantage is its appearance, but its drawback is that it ages in the mouth and becomes discoloured by bacteria, so it may need to be replaced.
This answer is for general information. Your own case needs an examination by an orthodontist.