Will a Retainer Fix a Mild Overbite Without Braces?

Although the word retainer, technically means to retain or hold previous treatment, some removable treatment appliances actually do correct overbites.  They are called Dentofacial Orthopedic Appliances and are inconspicous, removable and effective in correcting many jaw problems.  However, braces (or Invisalign) are usually needed to finish the result. 

If the teeth are protruded a little (2-3 mm),  there are some small spaces between them, and they don't have very much vertical overlap it may be possible.  If they protrude 4-5 mm, spaces need to be a little larger, and they must not have much vertical overlap.  With enough space the retainer could probably help this some.   Much more than these amounts of protrusion and it probably won't work.  If there is a lot of vertical overlap of the upper over the lower it probably won't work.  Best thing to do is go see an orthodontist and have him show you exactly what you have and what he thinks is the most practical way to treat it.  . You can ask why about anything he says  and he should be able to show you and explain it to you so that you really do understand exactly what the issues are.  If you don't feel that you really understand exactly what he is saying, go talk to another one until you do.  If you really understand what the retainer or whatever appliance that is recommended is supposed to do  your chance of getting a good result is a lot better.  Patient cooperation is essential and we really  need for you to be on the team to help get these things done. 

It all depends!...If your upper front teeth are flared out with spaces, it is certainly possible to retract the teeth until the spaces are closed....after this, any overjet would require much more extensive treatment. Without more information it's impossible to know what else you need.