I do a lot of long distance walking (10 to 20 miles a day with a 15 to 20 kg pack) and I find that to maintain a good bs level I can eat a Mars bar an hour :). If I do what my diabetes clinic recommend and eat slow release carbs I find d that I either have a lot of hypos or have to eat so many...
I work to the rule that if I feel a bit strange, do a test. It is the only way that you will start to relate the way that you feel to your blood sugar level.
I've got a small filling at the bottom of one of my front teeth, which I have had for several years. The difference in colour is so small that it doesn't show at all. Go for it!