I haven't had any cavities in over 20 years and now I'm told I have 2. The one tooth isn't even dark, but has a rough edge and I'm told it is soft. I was told by the dentist I lost a filling in that tooth, but I absolutely never had one in that tooth. First, does this sound for sure like a cavity? Second, why would I now get cavities, when I still brush and floss the same?
Sometimes as we age we create less saliva. That can account for a cavity.
A tooth doesn't have to look dark to have a cavity underneath. If you don't trust your dentist it's wise to get a second opinion.
I went for a second opinion and was told I only had the one cavity and had it filled. I don't understand why one dentist insists there is a cavity in the other tooth and the other says there is nothing to fill. This one tooth does look black along the gum line. Is it better to fill the tooth or not fill the tooth? I really don't want to seek yet another opinion just for a filling.
Diagnosing cavities seems like an obvious task but it can be quite difficult since teeth do not suddenly go from being healthy one day to having a hole the next. Using a car analogy, a cavity in a tooth is NOT like a having a perfectly solid windshield vs. one with a small chip or crack. It's more like a tire with various degrees of wear between being new and flat.
Some teeth are obviously heathy, some are obviously decayed but many are in that middle ground. Its very common for people to be cavity free many years then get a problem or two. Not good news but sometimes its a good wake up call for people who assume they are immune from cavities. This may not help your situation but it may be interesting. Good luck.