I have made some drastic lifestyles changes over the last year; I have been exercising very regularly, gone from being average to very fit, my skin has cleared up completely, my blood values have improved dramatically, et cetera.
About a month ago I realized there is one aspect of my health that has been going downhill, though, and that is my teeth. I never really payed attention to them when I was younger, so I really don't have anything to compare my current teeth status to, but I feel quite confident that they have become a lot more yellow.
I guess I can live with having a yellow tint to my teeth, but there is another thing that worries me far more: when I open my mouth in front of a mirror with strong lights I see subtle, vertical cracks on my front teeth, and small, black dots here and there. In addition to the small dots there is a larger, more noticeable dot on my upper left side, pretty far back. Also, the edges of the teeth look slightly transparent. My doctor suggested that this could be related to my low level of vitamin D intake, which led me to start taking a vitamin D supplement since about a month.
I know that bad dental hygiene can be a very bad thing for overall health, which is why I want to do something about this situation. I have a bunch of questions, primarily aimed at Oscar. Feedback would be GREATLY appreciated, as I am a bit worried about all of this.
1. Should I see a dentist as soon as possible, or would it be wise to wait and see what the vitamin D supplements will do for the transparent quality of my teeth?
2. Is it reasonable to assume that the black dots I see are cavities? If so, is it possible that these could heal themselves from increased vitamin D intake and extensive brushing/flossing twice a day?
3. Can cavities left untreated be bad for other - currently healthy - teeth, even if I take excellent care of my dental hygiene from this point forward?
4. In case I will need fillings, are there better materials than amalgam these days? I remember reading very scary stories about amalgam and how it is toxic to the body.
5. My current diet is largely juice based, primarily consisting of fruit juices and nut milks. I assume this is a good thing, considering that chewing solid foods obviously leads to food getting stuck in between teeth?
6. I have no pain anywhere in my mouth; is this a good sign? I like to think this means none of my hypothetical cavities can be THAT severe, but I really do not know much about these things (which should be clear from this post).

Sorry about a post on the rambly side, but all of this got me a bit worried. Any input would be greatly appreciated.
andyville.