Most dentists don't have any dental implants in their mouths either. But they have made a lot of legitimate income on marketing oral implants and providing implant services...much to the betterment of the public, and much to the betterment of the the incomes of their employees. Investors in companies that produce dental implants have prospered also.
I even knew an owner of a small town Chevrolet dealership who sold a ton of pickups, but never bought one himself.