Here is the problem with mounting a new front with the old stuff. It will be trash soon too. You have a stretched chain. It is past working limits and is showing this by deforming your sprocket teeth. All three items need to be replaced. If all things are kosher, and you lubricate properly, you should be able to get at least as many hours as you have on that set-up. Problem is when one item is off a bit, it can cause problems with the whole thing.
If you did in fact have a rock bend one of the front teeth, then this bent tooth can transfer uneven wear around the chain. This is a vicious circle that has no good end. One bad tooth can cause several bad links, several bad links can cause several bad teeth, and on and on and on....
Changing just one item of the set-up is a waste of money and time. It is all trash now.