Even if that was possible, which I'm sceptical of (you can already get toothpaste with antibiotics, you still need to use it regularly), I doubt that companies

Even if that was possible, which I'm sceptical of (you can already get toothpaste with antibiotics, you still need to use it regularly), I doubt that companies making a comfortable profit margin from non-commoditised toothpaste would be interested in that kind of innovation. They would stand to lose a lot from it. A new company could emerge with it, but they could equally disrupt a commoditised market.