Dear Andrey,
Unfortunately, Universität Hamburg does not offer any short-term MD study program for dentists. But maybe other German universities do offer such programs. You can do research on study programs offered throughout Germany via the database Higher Education Compass:
https://www.hochschulkompass.de/en/stud ... rmany.html
But note that, since medicine is a study program regulated by the state in Germany, it is very unlikely that you will find a short-term study program which will qualify you to practice as a doctor in a field different from dentistry in Germany.
Best regards,
Birte Schelling