Can i use my 5 year old retainers to push back my teeth a little like they were 5 yrs ago?

See orthodontist: It may or may not work, but it's generally not a good idea. It also depends on how your teeth have changed in the last 5 years. You should visit an orthodontist to be properly evaluated to see whether you need retainers. Maybe he/she can tell you if it is ok to reuse that old one. Invisalign is also an option for more minor corrections.

Yes: It can be done, but may be painful during the initial re-wearing. The pain is from putting strain on the wayward teeth in directions that they have not experienced for some time. If you feel comfortable, you could try putting the retainer in warm (not hot) water to reshape it. Of course this will lose the previous fit and may be best performed by a trained orthodontist.

Maybe: After a few years of not wearing retainers (made after getting teeth out of braces), one may or may not be able to still wear them. If the retainers can be put on, then the teeth probably only shifted slightly. The retainers might successfully move the teeth into the desired position. If the retainers are a tight fit, or don't fit at all, one can visit the orthodontist again for an evaluation.

Probably not: Before you attempt this, make an appointment with your orthodontist to verify that wearing the retainer will not, in fact, make things worse.

Oops: May be too late. This is why retainers must be worn exactly as prescribed. Take the retainers back to your orthodontist and let him check fit and efficiency. Ill fitting retainers can do all sorts of harm.