title: [Helicobacter pylori in dental plaque of periodontitis and gastric disease patients].
abstract: OBJECTIVE
  To investigate whether Helicobacter pylori(Hp) is a habitant in the oral cavity.
  
  
  METHODS
  A polymerase chain reaction (PCR) assay with oligonucleotide primers homologous to a portion of the urease C and cytotoxin-associated gene A (cag A) of Hp was used to test for the presence of Hp in dental plaque. This assay was able to detect the expected 294 bp and 400 bp DNA fragments from as few as 100 Hp cells per reaction. Thirteen gastric disease patients (Group G) and 10 periodontitis patients (Group P) were recruited. A total of 276 supra- and subgingival plaque samples were collected, from 6 teeth in each subject for PCR assay. Clinical periodontal parameters including probing depth (PD), bleeding index (BI) and plaque index (PLI) of the sampled sites were recorded.
  
  
  RESULTS
  In Group G, 11 of 13 patients had at least one Hp-positive plaque sample. 28.8% of the tested samples were urease C gene positive and 3.2% were positive for both urease C and cag A genes. All the 10 patients in Group P had at least one Hp-positive plaque sample. 49.2% of the tested samples were urease C gene positive and 3.3% were positive for both of the Hp genes. The prevalence of Hp was positively correlated with probing depth and bleeding index at the sampled sites.
  
  
  CONCLUSIONS
  These results suggest that oral cavity is an ecological niche of Hp.
authors.affiliation: School of Stomatology, Beijing Medical University, Beijing 100081.
authors.forename: W
authors.initials: W
authors.lastname: Hu
authors.forename: C
authors.initials: C
authors.lastname: Cao
authors.forename: H
authors.initials: H
authors.lastname: Meng
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D003773:Dental Plaque / Q000150:complications / Q000382:microbiology*; D005260:Female; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000150:complications*; D016133:Polymerase Chain Reaction; D013272:Stomach Diseases / Q000150:complications*; D014510:Urease / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C080866:cagA protein, Helicobacter pylori; D014510:Urease