Dr. E. Milburn Colvin Jr., 80, a Washington dentist for more than 50 years who was active in professional organizations, died Saturday in Fauquier Hospital in Warrenton, Va. He had cancer.

Dr. Colvin was president of the D.C. Dental Society from 1957 to 1958 and president of the D.C. Board of Dental Examiners from 1944 to 1945. He was a member of American Dental Association and a fellow of the American College of Dentists. From 1950 to 1972, he chaired a local Selective Service committee on the selection of dentists for military service.

Dr. Colvin was born in Washington and was a 1921 graduate of the University of Maryland's dental school in Baltimore. He practiced dentistry in Washington until retiring in 1974.

Since the 1940s, he had maintained homes in Washington and in Fauquier County, Va. He was a resident of Catlett, Va., at the time of his death. Dr. Colvin was chairman of the Fauquier County Planning Commission in the late 1960s and was the 1969 recipient of The Fauquier Democrat's "Freedom of Information" award for his civic contributions.

Survivors include his wife, the former Mildred Creel, and a brother, Dr. M. Hazen Colvin, both of Catlett.