Commander Dalen Quaice was a Starfleet physician who served on various planets and starbases during his long career. He was native to planet Kenda II, and was married to his wife, Patricia, for many years. Quaice was Beverly Crusher's mentor during her internship on planet Delos IV in 2352. They became good friends during that time. He was assigned to Starbase 133 in 2361.
Patricia died in 2367, and Quaice decided to retire and return to Kenda II. He was still in good spirits, but was somewhat depressed with the prospect of living the rest of his life and having to say goodbye to lifelong friends. He was picked up by the USS Enterprise-D during a crew rotation and ferried home soon afterward. While Quaice was on board, a warp bubble experiment run by Wesley Crusher trapped Dr. Crusher in an alternate reality where everything and everyone began disappearing, with only Crusher noticing the changes. Quaice was the first to vanish in this reality. (TNG: "Remember Me")