According to a report in the Süddeutsche Zeitung, the robbers broke into the dentist's practice in the small town of Fichtenwalde and brutally attacked him, slamming his head against a door frame.
The two men, believed to be aged about 20, then trapped the dentist's left index finger in a pair of garden shears and demanded money. Even though the victim gave them some cash, they then cut off his finger and fled.
Police have so far been unable to track them down, despite a large-scale investigation. The robbers are described as having an unkempt appearance and wearing hooded tops.
There is also no trace of the finger. The dentist, who was about to lock up for the evening, reportedly gave himself first aid and then sought help in a neighbouring shopping centre. He was given an emergency operation in the nearby town of Potsdam.