Background: The microorganism Helicobacter pylori has been closely linked to chronic gastritis, peptic ulcer, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Despite the current treatment regimens that lead to successful management of H. pylori-positive chronic gastritis, the reinfection rate is high. It has been suggested that one of the possible mechanisms of reinfection is the recolonization from dental plaque. The purpose of this study was to determine whether dental plaque, poor oral hygiene, and periodontal disease were risk factors for H. pylori infection.

Methods: Among the 134 patients, 65 patients who had a positive H. pylori serology or positive rapid urease test or histologic evidence for the presence of H. pylori in antral biopsy specimens were categorized as cases. The remaining 69 patients who were negative for H. pylori serology, the rapid urease test, and histology were controls.

Results: It was found that the association of periodontal disease and poor oral hygiene with H. pylori infection was not significant. There was a higher prevalence of H. pylori in the dental plaque of patients with gastric H. pylori infection than in controls, but both groups had a surprisingly high positive urease test for H. pylori in plaque (89% and 71%, respectively).

Conclusions: H. pylori in dental plaque is seldom eliminated by H. pylori-eradication therapy, and this may act as a source for future reinfection. Hence, eradication of H. pylori from the dental plaque should be made an important part of comprehensive management of H. pylori-associated gastric diseases.