Basic theory is that the bacteria of periodontal infections or infected teeth continuously infuse bacterial toxins and foreign bacterial antigens into the bloodstream, causing low-level inflammation throughout the body in various sites where these bacterial chemicals may concentrate.  Removing active oral infections can at least stop this one cause of chronic inflammation throughout the body.  Some body diseases have nothing to do with periodontal disease status and obviously will not be cured by curing periodontal disease or performing scaling/root planing to remove periodontal disease as a factor of chronic body inflammation at various body sites.  But in general, it is best to immediately remove any infection found anywhere in the body, to prevent a cascade of pathological events that can theoretically result from any chronic infection. 

A few times I have met patients who had a mouth full of infected broken teeth, and who were acting psychologically abnormally and irrationally.  They may have been resistant to removing the infected teeth due to their psychological state.  However, once convinced to remove the teeth, and the infections removed, their personalities changed almost overnight, making them calmer, more relaxed and more rational in their thought processes.  It is as if the bacterial toxins from the infections and the resultant body inflammation were causing them to think irrationally (which would be adaptive for the bacteria causing the infections, if this irrational thinking made the patients resistant to treating the infections), and once the bacterial infections and their related toxins were removed, the brain and body was under less inflammation, and the brain could think and emote more rationally.  Not an evidence based idea, but seems to have occurred this way clinically a few times.

John, thank you for your post.  As I was reading your thoughts and observations, I was thinking about the role pain may have played in irrational behaviors.  Once the pain was gone, the body relaxed and behaviors subsided.  That's just my thought on the behavior issues.  When I was Director of the dental program in rural Maine, I saw that behavior also, and depending on the 'stage' of the decay and abscessed of the teeth, behavior was different.  If the decay was advanced, there seemed to be an absence of pain, even though the infection was greater. If the infection was in the early stage there seemed to be more pain and the behavior was more intense.  

Your thoughts have given me an opportunity to research further, and a different angle or view point.  As a researcher who is trying to collect data, and get to the truth in the research, looking at every angle is vital.  Thank you again!

Sandy

Dear all, I think that this interesting article efeciently answers the current question. 

Good luck

Article Are periodontal diseases really silent? A systematic review ...

I concur with the response of John S Mamoun in relation to the basics but related to social change, poverty, literacy level and national policy are factors to reckon with in addressing chronic diseases.