This article states that Activator X was shown to dramatically reduce or eliminate L. Acidophilus in saliva but it doesn't mention it's effect on Streptococcus mutans, the primary cause of dental caries.
Studies have shown that L. acidophilus can inhibit the growth of candida albicans in the mouth so if it was to be eliminated, wouldn't the pH of the mouth become too alkaline and promote the growth of candida?
Also, if Activator X can eliminate L. acidophilus and other "friendly" bacteria in the mouth, what about the "friendly" bacteria living in the rest of our body? Does it kill that too? Sounds like an antibiotic effect to me. Am I missing something here?
Here is study stating that "probiotic ice-cream containing Bifidobacterium lactis Bb-12 ATCC27536 and Lactobacillus acidophilus La-5 can reduce the levels of certain caries-associated micro-organisms in saliva." - http://www.ncbi.nlm.nih.gov/pubmed/21466258