[Helicobacter pylori and the mouth cavity--overview and perspectives].

In view of the possibility of reinfection after successful treatment and the pitfalls in eradicating Helicobacter pylori (H. pylori) from gastric mucosa, it is of great interest to identify natural reservoirs for this organism, other than the stomach. This review discusses the results of investigations as to whether H. pylori can be harboured in the microaerobic environment of dental plaques in saliva. Only few data are available on the prevalence of H. pylori in the mouth. Data from conventional microbiological technique studies are contradictory, with the prevalence varying from 3.4% to 100%. Different diagnostic procedures were used to identify H. pylori, but only a few seem to be reliable enough to detect H. pylori in clinical samples taken from the mouth. Moreover, insufficient information is provided on the role of hygienic conditions in the investigated oral cavity and the existence of gingival or periodontal disease. The mechanisms of oral colonisation with H. pylori are still unknown. Human periodontal disease is associated with a complex microflora in which more than 350 microbial species can be encountered. The periodontal pocket may be important as a natural reservoir for H. pylori, because it can provide microaerobic conditions. Recently reported molecular techniques such as the highly sensitive and specific polymerase chain reaction (PCR) may help to clarify the prevalence of oral carriage of H. pylori in future.