It is difficult to eradicate Helicobacter pylori from dental plaque by triple therapy.

Background: Dental plaque has been suggested as a permanent reservoir of Helicobacter pylori (H. pylori) and a potential source of reinfection. The aims of this study were to investigate the presence of H. pylori in both dental plaque and the stomach and to evaluate the therapeutic effect of triple therapy on H. pylori in dental plaque.

Methods: Dental plaque and gastric biopsy samples were obtained from 65 patients with dyspeptic symptoms for endoscopic examination. The prevalence of H. pylori in dental plaque and stomach was determined with rapid urease test, histologic examinations and polymerase chain reaction assay based on the primer pair derived from the cagA gene of H. pylori. Triple therapy was administered to patients infected with H. pylori. H. pylori status was re-evaluated after eradication therapy.

Results: Prior to treatment, H. pylori was found in the stomach in 38 of 65 (58%) patients and in dental plaque in 28 of 65 (43%) patients. The coexisting infection rate of H. pylori in both stomach and dental plaque was 74%. After triple therapy, H. pylori was eradicated from the stomach in 32 of 38 (84%) patients, but only 2 of 28 (7%) patients with coexisting H. pylori infections of stomach and dental plaque showed the elimination of H. pylori from dental plaque.

Conclusions: The high coexisting infection rate of H. pylori in both stomach and dental plaque implies that dental plaque can serve as another reservoir of H. pylori. H. pylori in dental plaque was hardly eradicated by triple therapy. Dental plaque may be a potential source for recrudescence of gastric infection after successful systemic therapy.