Dear lybrate user!
It is must to wear retainer after dental brace removal for adequate time. The main purpose of using orthodontic retainer is to stable the teeth moved in new place with the help of orthodontic braces. So don't use a repaired retainer due to loss of it's ability to perfectly retain your orthodonticaly moved teeth. Ask your orthodontist
for new retainer. You can also ask your orthodontist for wire free retainer with teeth slot in it. It is more comfortable than wired retainer.