title: The frequency of Helicobacter pylori in dental plaque is possibly underestimated.
abstract: OBJECTIVE
  The commonest bacteria, causing infection across the world is Helicobacter pylori, which colonizes the human stomach. This bacteria has also been detected in some extra-gastric ecological niches such as the oral cavity and water. However, the results of H. pylori detection in extra-gastric ecological niche are controversial. The improvement of the sensitivity and the specificity of the detection methods appear to be some of the main bottleneck issues in providing compelling evidence. The aim of this study was to detect the presence of this organism in dental plaque samples using an analytically sensitive and specific Polymerase Chain Reaction (PCR) as well as a new nucleic acid detection method termed the Loop-mediated Isothermal Amplification (LAMP).
  
  
  METHODS
  In a descriptive cross-sectional study 45 participants enrolled and dental plaque samples were collected from at least two teeth surfaces (one anterior and one posterior tooth) using a sterile periodontal curette. The DNA content was extracted from the samples and the presence of H. pylori was determined by PCR and LAMP reactions.
  
  
  RESULTS
  The frequency of detection of H. pylori in the dental plaque samples were 44% (20/45), 66.67% (30/45) and 77.78% (35/45) using PCR, LAMP and positivity for both tests, respectively.
  
  
  CONCLUSIONS
  The high frequency of H. pylori was detected in the dental plaque samples of the participants, which concurs with the high prevalence of this bacteria in the population. This is one of the highest reported rates around the world. The results reveal that dental plaque can be one of the main causes of re-infection and also be the cause of oral-oral transmission.
authors.affiliation: Department of Microbiology, Qom Branch, Islamic Azad University, Qom, Iran. Electronic address: negin.amiri21@gmail.com.
authors.forename: Negin
authors.initials: N
authors.lastname: Amiri
authors.affiliation: Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran. Electronic address: ramin_abiri@yahoo.com.
authors.forename: Ramin
authors.initials: R
authors.lastname: Abiri
authors.affiliation: Department of Periodontics, Faculty of Dentistry, Kermanshah University of Medical Sciences, Kermanshah, Iran. Electronic address: masoomeeivazi@yahoo.com.
authors.forename: Masoumeh
authors.initials: M
authors.lastname: Eyvazi
authors.affiliation: Department of Microbiology, Qom Branch, Islamic Azad University, Qom, Iran. Electronic address: mreza.zolfaghary@gmail.com.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zolfaghari
authors.affiliation: Department of Microbiology, Faculty of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran. Electronic address: ah_alvandi@yahoo.com.
authors.forename: Amirhooshang
authors.initials: A
authors.lastname: Alvandi
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D003773:Dental Plaque / Q000382:microbiology*; D005260:Female; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D016133:Polymerase Chain Reaction
keywords: Dental plaque; Helicobacter pylori; LAMP; PCR