The importance of the specific bacteria to the prognosis of an individual’s case of gum disease was known over 20 years ago. In a 1996 article in the Journal of Periodontology (Renvert et al. J Periodontol. 1996 Jun; 67(6): 562-71.) the authors concluded that the presences of Aa, Pg, and Pi alone or in combination correlated with attachment level changes. The authors further concluded that pathogenic bacteria are better predictors of disease progression than observed clinical signs. In a 200...