In my second-last molar teeth cavity started forming few months back. I didn't cared much as it used to happen before and go away on its own. However, yesterday I noticed a tiny black hole in the middle of the teeth, which got me worried. So I was wondering if some flouride treatment and staying away from sugar could get rid of the cavity, or the matter are worse now and I must see a dentist? And if I do have to see a dentist, will he provide some passive solutions or directly use treatments like filling or crown, etc.?