This has to be weighed against anecdotal evidence ( good anecdotal evidence is IMO better than your average study/research) from vegans. Vegans tend to have very high occurrence of cavities despite the best of oral hygiene. ( source ex-vegans on their blogs etc.) Eskimos when first discovered by western explorers had a complete absence of cavities despite bad oral hygiene and a diet of almost no plants (Source: A book written by an explorer, whose name I cannot remember)

Greger's site. About what I was expecting...