1) Taro and Sweet Potatoes were staples of orally healthy Hawaiian individuals and they had bone structures that could support frames we would call giant now days. The diet included 60-70% of calories from sweet potatoes and Taro with most of the rest being seafood/fruits/coconuts/shellfish/pork. When these Hawaiian children were given grains/rice instead they developed rampant decay, and when they reverted to the traditional whole foods it stopped according to this journal.
2) In the mid-late 1700's Hawaiians were rather tall (their king at the time was 7ft and his wife was 6'6"), the royal class was generally 6'+. http://pleasantfields.com/heritage/2011/04/23/race/ and https://www.google.com/search?q=how+tall+was+Kamehameha+I&rlz=1C1GGGE_enUS414US414&oq=how+tall+was+Kamehameha+I&aqs=chrome.0.57j60j0j60j5j0.2296&sourceid=chrome&ie=UTF-8 . Tooth Decay was rare or unknown and they had wide dental arches. Their rate of cavities was better than the Eskimos Weston Price examined.
3) looks at the phytic acid content of different tubers and finds that while taro is one of the highest they measured, sweet potatoes had no measurable phytate/phytic acid.
I'm not making the case for more carbs. Weston Price believed the mouth was a window to overall health and I've always thought that all starchy carbs (rice, potatoes, wheat) would be equally bad for the teeth. But apparently Sweet Potatoes have an either nil to positive effect on Dental health. Did you know about how Sweet Potatoes effect Dental Health? If you read the first source, what do you think about the conclusions they drew as to the alkalinity of rice vs Sweet Potatoes? I always thought it was total crock, but they make a case for alkaline/acid foods none the less and they tie it into climate which I think is cool.