Focal infection theory

Roots and dawn Germ theory Hippocrates, in ancient Greece, had reported cure of an arthritis case by tooth extraction.—whereby Koch announced discovery of the "tubercle bacillus" in 1882, fully premising the modern principle of focal infection. In 1884, William Henry Welch, tasked to design the medical department at the newly forming Johns Hopkins University, imported the German model, "scientific medince", to America. As progressively more diseases drew an infectious hypothesis that led to a pathogen discovery, conjectures grew that virtually all diseases are infectious. In 1890, German dentist Willoughby D Miller attributed a set of oral diseases to infections, and attributed a set of extraoral diseases—as of lung, stomach, brain abscesses, and other conditions—to the oral infections. In 1894, Miller became the first to identify bacteria in samples of tooth pulp. Miller advised root canal therapy. Around 1900, British surgeons, still knife-happy, were urging "surgical bacteriology". Its success funded Pasteur's formation of the globe's first biomedical research institute, the Pasteur Institute. Later the institute's director and a 1908 Nobelist, Metchnikoff believed, as did his German immunology rival Paul Ehrlich—theorist on antibody, mediating acquired immunity—and as did Pasteur, too, that nutrition influences immunity. Metchnikoff reasoned that the colon functions as a "vesitigal cesspool" that stores waste but is unneeded. Abdominal surgery's pioneer, Sir Arbuthnot Lane, based in London, drew from Metchnikoff and clinical observation to identify "chronic intestinal stasis"—in lay terms, intractable constipation—presumably, "flooding of the circulation with filthy material".—medical doctors who recognized "focal infection" were hinting a scientific basis versus the older, alleged "health faddists" like medical doctor Kellogg and like minister Sylvester Graham. In 1910, lecturing in Montreal at McGill University, Hunter declared, "The worst cases of anemia, gastritis, colitis, obscure fevers, nervous disturbances of all kinds from mental depression to actual lesions of the cord, chronic rheumatic infections, kidney diseases are those which owe their origin to or are gravely complicated by the oral sepsis produced by these gold traps of sepsis." Ten years later, he proudly accepted that credit. And yet, read carefully, his lecture asserts a sole cause of oral sepsis: dentists who instruct patients to never remove partial dentures. Billings & Rosenow Focal infection theory's modern era really began with physician Frank Billings, In 1916, Billings lectured in California at Stanford University Medical School, this time printed in book format. Billings thus popularized intervention by tonsillectomy and tooth extraction. Preeminent recognition Since 1889, in the American state Minnesota, brothers William Mayo and Charles Mayo had built an international reputation for surgical skill at their Mayo Clinic, by 1906 performing some 5,000 surgeries a year, over 50% intra-abdominal, a tremendous number at the time, with unusually low mortality and morbidity. Though originally distancing themselves from routine medicine and skeptical of laboratory data, they later recruited Edward Rosenow from Chicago to help improve Mayo Clinic's diagnosis and care and to enter basic research via experimental bacteriology. At Johns Hopkins University's medical school, launched in 1894 as America's first to teach "scientific medicine", the eminent Sir William Osler was succeeded as professor of medicine by Llewellys Barker, who became a prominent proponent of focal infection theory. cast support. famed author of ''Cecil's Essentials of Medicine, too, lent support. By 1930, excision of focal infections was considered a "rational form of therapy" undoubtedly resolving many cases of chronic diseases. then a related article in the Journal of the American Medical Association'' in 1925. Price concluded that after root canal therapy, teeth routinely host bacteria producing potent toxins. his 1925 debate with John P Buckley was decided in favor of Price's position: "practically all infected pulpless teeth should be extracted". As chairman of the American Dental Association's research division, Price was a leading influence on the dentistry profession's opinion. Into the late 1930s, textbook authors relied on Price's 1923 treatise. In 1911, the year that Frank Billings lectured on focal infection to the Chicago Medical Society, unsuspected periapical disease was first revealed by dental X-ray. dental radiography to feed the "mania of extracting devitalized teeth". Kells, too, advocated conservative dentistry. In 1907, psychiatrist Henry Andrews Cotton became director of the psychiatric asylum at Trenton State Hospital in the American state New Jersey. Influenced by focal infection theory's medical popularity, Despite skepticism in the profession, psychiatrists sustained pressure to match Cotton's treatments, as patients would ask why they were being denied curative treatment. Cotton had his two sons' teeth extracted as preventive healthcare—although each later committed suicide. In the 1930s, however, focal infection fell from psychiatry as an explanation, Cotton having died in 1933. ==Criticism and decline (1930s–1950s)==

Early skepticism Addressing the Eastern Medical Society in December 1918, New York City physician Robert Morris had explained that focal infection theory had drawn much interest but that understanding was incomplete, while the theory was earning disrepute through overzealousness of some advocates. Morris called for facts and explanation from scientists before physicians continued investing so steeply in it, already triggering vigorous disputes and embittering divisions among clinicians as well as uncertainty among patients. largely discussing focal infection theory, which Kells condemned as a "crime". Kells urged dentists to reject physicians' prescriptions of tooth extractions. Focal infection theory's elegance suggested simple application, but the surgical removals brought meager "cure" rate, occasional disease worsening, and inconsistent experimental results. As colleagues of Kirby, two researchers—bacteriologist Nicolas Kopeloff and psychiatrist Clarence Cheney—ventured from Ward's Island to Trenton, New Jersey, to investigate Cotton's practice. Publishing two papers, the team presented the findings at the American Psychiatric Association's 1922 and 1923 annual meetings. At Johns Hopkins University, Phyllis Greenacre questioned most of Cotton's data, and later helped steer American psychiatry into psychoanalysis. In the 1930s and 1940s, researchers and editors dismissed the studies of Price and of Edward Rosenow as flawed by insufficient controls, by massive doses of bacteria, and by contamination of endontically treated teeth during extraction. They commented, "Focal infection is a splendid example of a plausible medical theory which is in danger of being converted by its enthusiastic supporters into the status of an accepted fact." Fish reported that the first zone was the zone of infection, whereas the other three zones—surrounding the zone of infection—revealed immune cells or other host cells but no bacteria. Amid improvements in endodontics and medicine, including release of sulfa drugs and antibiotics, a backlash to the "orgy" of tooth extractions and tonsillectomies ensued. A 1952 editorial in Journal of the American Medical Association tolled the era's end by stating that "many patients with diseases presumably caused by foci of infection have not been relieved of their symptoms by removal of the foci", that "many patients with these same systemic diseases have no evident focus of infection", and that "foci of infection are as common in apparently healthy persons as in those with disease". Although some support extended into the late 1950s, focal infection vanished as the primary explanation of chronic, systemic diseases, and the theory was generally abandoned in the 1950s. ==Revival and evolution (1990s–2010s)==

Despite the general theory's demise, focal infection remained a formal, if rare, diagnosis, as in idiopathic scrotal gangrene and angioneurotic edema. Meanwhile, by way of continuing case reports claiming cures of chronic diseases like arthritis after extraction of infected or root-filled teeth, and despite lack of scientific evidence, "dental focal infection theory never died". Conversely, attribution of endocarditis to dentistry has entered doubt via case-control study, as the species usually involved is present throughout the human body. Stealth pathogens With the 1950s introduction of antibiotics, attempts to explain unexplained diseases via bacterial etiology seemed all the more unlikely. By the 1970s, however, it was established that antibiotics could trigger bacteria switch to their L phase. Eluding detection by traditional methods of medical microbiology, bacterial L forms and the similar mycoplasma—and, later, viruses—became the entities expected in the theory of focal infection. or from oral tissues and the intestines, especially during dysbiosis. Apparently, dental infections, including by uncultured or cryptic microorganisms, contribute to systemic diseases. Periodontal medicine At the 1990s' emergence of epidemiological associations between dental infections and systemic diseases, American dentistry scholars have been cautious, Some American sources emphasized epidemiology's inability to determine causality, categorized the phenomena as progressive invasion of local tissues, and distinguished that from focal infection theory—which they assert was evaluated and disproved by the 1940s. European sources find it more certain that dental infections drive systemic diseases, at least by driving systemic inflammation, and probably, among other immunologic mechanisms, by molecular mimicry resulting in antigenic crossreaction with host biomolecules, while some seemingly find progressive invasion of local tissues compatible with focal infection theory. a stance matched in Indian literature. Thus, there has emerged the concept periodontal medicine. jawbone cavitations are recognized as foci also in osteopathy but conventional dentists generally conclude them nonexistent. and allegations of quackery persist. Huggins and many biological dentists also espouse Weston Price's findings on endodontically treated teeth routinely being foci of infection, Conventional belief is that microorganisms within inaccessible regions of a tooth's roots are rendered harmless once entrapped by the filling material, although little evidence supports this. and E H Ehrmann in 1977 had dismissed any relation between endodontics and focal infection. The traditional root-filling material is gutta-percha, whereas a new material, Biocalex, drew initial optimism even in alternative dentistry, but Biocalex-filled teeth were later reported by Boyd Haley to likewise seep toxic byproducts of anaerobic bacterial metabolism. Seeking to sterilize the tooth interior, some dentists, both alternative and conventional, have applied laser technology. Although endodontic therapy can fail and eventually often does, dentistry scholars maintain that it can be performed without creating focal infections. ==Footnotes==