I've had these spots on my teeth near my gumline for about 1.5 years now, and they've slowly been getting worse. I saw my dentist about 6 months ago, when I inquired, he said "they look like they may be the start of cavities", and offered no further insight or solution. I smoke cigarettes & drink coffee, I don't regularly take any medications, aside from a z-pack 2-3 times a year (I get chronic sinus infections/bronchitis). I brush thoroughly twice a day, and floss every evening before bed.