Bentoiu studied harmony, counterpoint and composition with Mihail Jora and piano with Teophil Demetriescu. He spent three years researching the rhythm and harmony of Romanian folk music at the Bucharest Folklore Institute and then began composing for the stage. His operas are written with dramatic flair and make use of a variety of elements, including folksong, tape, serialism and diatonic qualities. His instrumental and orchestral works also contain a variety of contemporary techniques, and Bentoiu’s work is characterized by its color and lyricism.
He has edited the sketches of the fourth and fifth (1941) symphonies of Georges Enescu into shape for performance. (There is a recording of both realizations from a 1998 festival.)