That cast can be welded. Take it to a shop where they have Stainless Steel rod. A good welder will be able to rebuild those teeth. They have to be carefull to not get the cast too hot, but it can be done. I have added metal to worn teeth and then ground them down to the right shape. The trick here is finding a Welder' s welder. (In other words, a master welder.)

Russ