It may be wise to detox gently. Perhaps you should try taking Algin daily for a couple weeks and see if you notice a change. It does wonders for me and would help indicate a heavy metal -related issue.

Also, make sure there isn't any other dietary change that could be the cause. For example, do you have NutraSweet (aspartame)? Any other dietary changes? Flu shot (it contains mercury)?

It makes most sense that the visit to the dentist was the culprit but it's always good to explore all possibilities.