Funny thing: none of the other primates brush their teeth or suffer gray matter shrinkage, or neuro-degenerative diseases, or Alzheimer’s. I smell a simple commordity.
The human fossil record is pretty short on cavities, as are the rare hunter-gatherer societies still remaining. All these problems arose with the adaptation of agriculture and a processed, grain-based diet.
Are you sure of that. . . or have they just not lived long enough with a large enough population to experience it? The disease progression has a minimum 30-40 year progression before even the most minimal symptoms appear in humans? How many chimps, great apes, etc, live that long? Has anyone done a study of dementia in aging ape populations? How about diabetic apes? Chronic heart and artery disease in great apes in a large population as they age? Not an easy thing to do.
We are even having trouble getting a large data base of the flora and fauna in the mouths of older people. We've enlisted a lot of dentists to do it and what we are finding is consistent but it needs to be studied more than the population of people who go to the dentist! For the most part, that's a self-selected population of people who care for their oral hygiene. We should be checking all ages in all types of people over a long period. That takes funding and many people participating. . . plus we need to look at other factors.
I would agree that there may be some other factors at work as well. . . we just don't know at this point. However, all of these diseases rose during he 20th Century to epidemic proportions in the populations and also spread with the use of toothpaste over the use of alternative means of teeth cleaning and oral hygiene. The correlation is striking as those American practices spread throughout the world, followed consistently 20-50 years later by an extraordinary rise in these diseases associated with oral spirochetes.
Hell, the level of research on spirochetes is so low we do not even know how they reproduce or where! Their life cycle is unknown. There is a theory they can only reproduce in the mouth. . . which would be a blessing. But how do you remove them once they've entered the blood stream? They don't seem to respond well to antibiotic therapies. Some have been affected by raising the blood levels of chlorine. . . but that's not a good treatment modality, but it does seem to kill blood borne spirochetes. Another means is ozone therapy.