After World War II, di Maria Petris got divorced and moved to Finland, where she made a career as a voice teacher; among her many students is Jaakko Ryhänen, who credits her as his most influential tutor.[3] She was appointed as a singing instructor at the Sibelius Academy in 1960.[1] She also judged several international singing competitions from the late 1950s until the mid-1970s.[1]