This happened to me a few years ago when I had numerous cavities and other dental problems after my dental check up. Contemplating a lot of painful procedures and thousands of dollars in Dental bills I became almost compulsive about brushing my teeth. Every time I eat anything I have to brush! Not only do I like the way it feels, I can't stand the thought of all that bad bacteria having its way with my teeth & gums :)
So, the happy ending is that since this time I have not had any cavities, my gums, which were bleeding and starting to receed have become much more healthy - my Dentist is amazed!
I guess this is a good thing. Some even say I am obssessed but that is fine, as long as it makes my mouth healthier then I guess I will have OCD any time.