German law requiring dentists to retire at age 68 is justifiable as a proportionate means to achieve legitimate aims (ECJ Advocate General's opinion - a ruling by the Court is still awaited).
Under German law (Gesetz zur Sicherung und Strukturverbesserung der gesetzlichen Krankenversicherung of December 1992), there is a general rule, subject to certain specified exceptions, that the licences which enable doctors and dentists to practice must expire and not be renewed when, or shortly after, they attain age 68.