My backhoe with 4 in 1 bucket does have replaceable teeth on its cutting edge but I noticed most backhoes do not. Why? It seems having teeth would usually be an advantage trying to load from a compacted or rocky pile or dig from loader bucket.
Most operators use the front bucket to load loose material and do fine grading. The tooth marks are not so good when putting down cold mix on a job, for example. If the digging is hard enough to warrant it, I flip around and tear out a bunch with the backhoe bucket. That is always a good option, and easier on tires etc rather than trying to power it out of the bank.
What he said. Loader/backhoe isn't really designed to "dig" with the front bucket, that bucket is more for moving material, digging is done by the hoe.
I put bolt on teeth on my general purpose bucket and ended up doing way more damage to the bucket than it was worth. I took them off and put the straight cutting edge back on.