Dr. Clarence O. Lewis 67, a Washington dentist for 35 years and a former president of the D.C. Board of Dental Examiners, died Monday at his home in Silver Spring after a hear attack.

He served on the board before being elected president in 1958. He also was a member of the Northeast Regional Board of Dental Examiners from 1956 to 1979, and was a consultant to that group until his death.

Dr. Lewis was a native of Washington and a 1929 graduate of Dunbar High School. He graduated from Howard University in 1935 and from its dental school four years later.

He served as a dentist with the Army in Italy and North Africa and retired from the Army reserves in 1972 with the rank of major.

Dr. Lewis resumed his private dental practice in Washington, which had been interrupted by the war, in 1947.

He was a member of the Robert T. Freeman Dental Society of the National Dental Association and the D.C. Dental Society of the America Dental Association. He also was a member of the American College of Dentists.

Dr. Lewis had served as a consultant to the State Department for the past several years.

Survivors include his wife of 38 years, the former Hilda Evans, of Silver Spring; a son, Clarence III, of Marlow Heights; a daughter, Hilda E. Lewis of Nevada, and a sister, Ruth Dixon of Washington.