He had dentures made of human teeth, human teeth dentures were almost always made from slave teeth during this time.

Put it this way. No one in their right mind would have their healthy teeth pulled out without anaesthetic and sell them, if they had any real choice.

We know that he "bought" teeth from slaves, and that he was a slave owner, we also know that he had dentures made of other people's teeth. No one knows for sure that the teeth he took were for his own use or from the people he enslaved himself, but it seems probable. More info here.