In most cases, no. A bent antenna is never going to be as good as a brand new one, but there are a few exceptions. If the antenna is really, really old, it may have just been hinges that wore out, not the antenna elements themselves. In that case you may be able to shim or repair the hinges to restore an older antenna to good-as-new status. Antennas made 50 years ago tend to be more durable because people paid a lot more money for them than they would now.
For the most part you are much better off getting a new antenna. There’s no point to repairing an old antenna when today’s antennas are designed for today’s needs. If you’ve got an old yagi-style antenna then at least a quarter of its elements aren’t used anymore. Newer antennas are better engineered for today’s TV broadcasting.
If you are thinking of getting a new antenna, I hope you’ll consider shopping at Solid Signal, as they do keep the lights on here.