You can find a dentist via the internet, for example in Hamburg: https://www.aerztekammer-hamburg.org/arztsuche.html
In case of a dental emergency You can call 04018030561. There is a local dentist ambulance in Hamburg from 7 p.m. till 1.a.m. at the Stresemannstraße 52, 22769 Hamburg (Altona). For further information, please visit https://www.zahnarzt-notdienst.de/notdienst/0/hamburg-040.php