Focal Infection Theory - Evolution and Revival of FIT

Evolution and Revival of FIT

However, the fall of focal infection theory as primary cause of systemic disease did not mean the theory itself did not continue to find enough supporters to appear in textbooks such as Dougherty's 1954 Textbook of bacteriology regarding teeth and peer reviewed papers such as Galloway's 1957 JAMA article on tonsillectomies and as late as 1986 it was stated "(t)oday, in spite of a decline in the recognition of the focal infeciton theory the association of decayed teeth with systemic disease is taken very seriously."

Furthermore the mechanism of focal infection theory survived in general medicine with regards to specific diseases such as tuberculosis, gonorrhea, syphilis, pneumonia, typhoid fever, and mumps as well as conditions such as idiopathic scrotal gangrene and angioneurotic edema.

Finally a continual influx of new cases demonstrating its possible validity (as well as the fact that the behavior of untreated tooth abscess fitted the classic definition) kept the concept alive in the dental community

All these factors have resulted in a disagreement not only about when focal infection theory fell out of favor but also the degree to which it did. For example in 2002 Ingle's Endodontics 5th edition stated "(i)n the 1930s, editorials and research refuted the theory of focal infection". while 2006 Carranza's clinical periodontology stated "(t)he focal infection theory fell into disrepute in the 1940s and 1950s", and the 2009 Textbook of Endodontology stated that while it had lost its influence "dental focal infection theory never died"

In 1989 a respected study showed a significant correlation between poor dental health and myocardial infarction, which was followed by other studies showing similar results, prompting the dental community to do a cautious reevaluation of focal infection theory. By 2006 the idea that some aspects of focal infection might be valid was finding greater validity especially in immunocompromised people.

In 1994 George E. Meinig published Root Canal Cover-up Exposed which resurrected the old studies by Rosenow and Price, raising the concern among dentists that patients hearing about these studies might view them as new and reliable. Hasselgren stated in New York Academy of Dentistry's Annals of dentistry that Meinig's book was in major need of professional editing, used Price's 1923 Dental Infections, Oral and Systemic (but not his other works), made unsubstantiated claims, confused the meaning of terms (such as infection and inflammation), and expanded into areas unrelated to the main topic to the point Hasselgren ends the review with the comment "I wonder how the serious researcher Weston Price would have reacted to the way his work has been presented." Hasselgren observed, "he focal infection theory, supported by many including Dr. Price, has been attacked, debated, accepted, criticized, agreed upon, etc. but it has not been covered up." Of modern dentistry he noted, "many clinicians appear today to have lost sight of the fact that endodontical treatment shall be based on biology and not on the use of various gadgets to sweep canals. Also, one-visit treatment of necrotic, infected teeth is being advocated and practiced even if no long-term study has been performed to investigate this kind of treatment. The work of Dr. Weston Price is therefore still to a great extent valid and important and the role of infection can not be underestimated."

In a 2000 issue of the Journal of the California Dental Association Pallasch stated "The focal infection theory was (is) elegant in its simplicity and offered quick and easy (as well as lucrative) solutions to a myriad of problems for which medicine had no answers. It also afforded medicine the chance to deflect the blame from its ignorance to relative defenseless and unwitting victims: dentists and patients. All of its proponents were infected with the concept that "after it, because of it" for which even today there is no vaccine. Bearing the above in mind, it is useful to now examine the resurgence of the focal infection theory of disease in its newer guises." In a 2003 issue of Endodontic Topic Pallasch expressed concern that these studies would be greeted with the same over enthusiasm that Weston Price's and Edward C Rosenow's rabbit experiments had been back in the 1920s and that said dentists advising dental treatment to reduce patient's risk for myocardial infarction or stroke were giving advice no more scientific then the ‘100 percenters’, ‘therapeutic edentulism’ and ‘clean sweep’ advice given in the heyday of focal infection theory.

In the introduction to a supplement of the Journal of the American Dental Association dedicated to this renewed interest, Micheal L. Barnett states that "he investigation into oral-systemic disease connections is a rapidly advancing area of research." Barnett cautions his readers that it is important to distinguish between data that merely suggest correlations between oral infection and systemic disease and data that show a causal relationship. With that in mind, the articles in the supplement investigate "the connection between dental plaque and periodontal disease and adverse pregnancy outcomes, cardiovascular disease, bacterial pneumonia and diabetes."