There's a ton of misinformation out there regarding mercury toxicity and its relationship to yeast infections. While mercury is toxic and can impact your immune system (which in turn can contribute to the development of chronic Candida), there is no scientific proof or study that proves that mercury causes Candida. Many people recommend having your mercury fillings taken out and replaced with white composite fillings, there is nothing to prove your Candida problems will be cured (though getting rid of the toxins will still help your overall health). At the very least, don't let your doctor give you any more “silver” (aka mercury-laden) fillings.
There's an awful lot to be said about Candida. A Candida overgrowth can make your life miserable and needs to be taken seriously in order to be realistically treated. Do your best to find a resource you can trust and don't fall for the myriad of scams and misinformed individuals claiming to have the magic cure. Overcoming Candida takes time and work, but it can be done.