Can you insert probiotic supplements into the vagina to cure/prevent chronic yeast infections and if so is there a certain brand or type to use?

Not yet: Note yet, at least not with any degree of certainty. However, research is ongoing, looking at which species and strains of microorganisms might someday be able to re-colonize the vagina and prevent overgrowth by fungi (ie, Candida) or other microbes ("BV"). Hopefully someday soon we will be able to apply "normal microbial flora" instead of antibiotics.