This is going back a bit, but my school was full of them; mostly Army, but I remember a few Navy too. One always had to refer to them as Major xxx, Commander yyy, Capt zzz etc. Even at the time it seemed a bit weird; one teacher I never got on with insisted on being called Lieutenant xxxx, which said a lot in hindsight.
I have a number of good friends with PhDs, never once heard any of them referred to as Dr xxxx, even in a professional capacity.