Is the presence of Helicobacter pylori in the dental plaque of patients with chronic periodontitis a risk factor for gastric infection ?

1College of Dentistry; 2Department of Gastroenterology, College of Medicine, King Saud University, Riyadh, Saudi Arabia Correspondence: Dr Waleed Khalid Al-hamoudi, College of Medicine, King Saud University, University Road, Riyadh, Central province 10774, Saudi Arabia. Telephone 966-505-240588, fax 966-146-71217, e-mail walhamoudi@gmail.com Received for publication September 4, 2008. Accepted October 30, 2008 H pylori is a microaerophilic, Gram-negative, spiral and mobile bacterium that is believed to be one of the major factors responsible for gastritis, gastroduodenal ulcers and gastric cancer (1,2). Studies have identified the microorganism in dental plaque and saliva, implicating the oral cavity as a potential reservoir for H pylori or as a possible route of transmission to other sites. The oral cavity can act as an extragastric reservoir for H pylori, which may lead to recurrent gastric infection (3). Avcu et al (4) observed that patients with poor oral hygiene were most likely to have H pylori in the oral cavity. They also suggested that H pylori could recur in the stomach of these patients after triple therapy more frequently than in patients with good oral hygiene. The findings of Andersen et al (5) justify the suggestion that dental plaque serves as a reservoir for this pathogen. They demonstrated the ability of H pylori to coaggregate with Fusobacterium nucleatum and Fusobacterium periodonticum, which are early and late colonizers, repectively, of the mouth. Dye et al (6) found a positive association between H pylori seropositivity and periodontitis in an epidemiological study. They suggested that periodontitis can be a risk factor for H pylori infection. Umeda et al (7) compared the prevalence of H pylori in patients with and without periodontal pockets and showed a higher prevalence of the bacteria in patients with deep periodontal pockets. In contrast, other studies (8-10) failed orIgInal artIcle


Is the presence of Helicobacter pylori in the dental plaque of patients with chronic periodontitis a risk factor for gastric infection?
M Al Asqah, N Al Hamoudi, S Anil, A Al jebreen, WK Al-hamoudi.Is the presence of Helicobacter pylori in the dental plaque of patients with chronic periodontitis a risk factor for gastric infection?Can J Gastroenterol 2009;23(3):177-179.
BACKGROUND: Helicobacter pylori is considered to be a pathogen responsible for gastritis and peptic ulcers, and a risk factor for gastric cancer.A periodontal pocket in the teeth of individuals with chronic periodontitis may function as a reservoir for H pylori. OBJECTIVE: The present study was undertaken to evaluate whether the presence of H pylori in the dental plaque of patients with and without periodontitis correlates with gastric involvement.METHODS: A total of 101 patients with dyspepsia were included in the present study.Subjects were divided into periodontitis and nonperiodontitis groups.For the detection of H pylori in dental plaque, samples were collected from two teeth using a periodontal curette.Subgingival plaque was obtained by inserting two sterile paper points into periodontal pockets for 20 s.This was followed by an upper gastrointestinal endoscopy and antral biopsies.RESULTS: Sixty-five per cent of patients had dental plaque positive for H pylori and more than 50% harboured the bacteria in their stomach.Periodontitis patients had a significantly higher percentage of H pylori in their dental plaque (79% versus 43%; P<0.05) and the stomach (60% versus 33%; P<0.05) than patients with no periodontitis.Additionally, 78% of patients from the periodontitis group versus only 30% from the nonperiodontitis group had a positive test result for the coexistence of H pylori in both dental plaque and the stomach.CONCLUSION: Patients with poor oral hygiene have a higher prevalence of H pylori in dental plaque and in the stomach.This finding suggests that the oral cavity may be a reservoir for H pylori, and potentially a source of transmission or reinfection.to detect H pylori in the subgingival plaque of patients with a gastric infection.
Studies regarding the prevalence of H pylori in dental plaque, and its correlation with systemic conditions are inconclusive.The present study is one of the very few conducted to evaluate the prevalence of H pylori in both dental plaque and the gastric mucosa of symptomatic patients admitted to a gastroenterology department.

METHODS
One hundred one patients attending the gastroenterology unit of the King Saud University Hospital, Riyadh, Saudi Arabia, were asked to participate in the study.The purpose of the study was explained to the patients and consents were obtained.The study was approved by the hospital's ethics committee.All patients had a complaint of dyspepsia and underwent gastroscopy and antral biopsies.Biopsy samples were analyzed immediately using a rapid urease test kit.
All selected patients were nonsmokers, and the following exclusion criteria were used to achieve a more homogenous study population: diabetes, pregnancy, HIV-positive, previous treatment of a peptic ulcer, cancer, antibiotic therapy during the previous two months, periodontal therapy within the past year, signs of severe periodontal infection, severe dental caries and the recent use of nonsteroidal anti-inflammatory drugs.
Based on periodontal status, subjects were divided into two groups (with and without chronic periodontitis).Only patients exhibiting bleeding on probing and at least four teeth with a probing depth of 3 mm or more were assigned to the chronic periodontitis group (n=62).The remainder of the individuals were considered healthy oral cavity subjects (n=39).The probing depth, plaque index, bleeding on probing and clinical attachment level were recorded by the same investigator.
For the detection of H pylori in dental plaque, samples were collected from the oral cavity after the clinical periodontal examination.A sterile universal curette was used to collect plaque samples from two teeth with deep periodontal pockets.
The rapid urease test H pylori was detected by a commercially available rapid gastric urease test kit (Lencomm Trade International, Poland).The samples were immediately inoculated into the rapid urease test gel.If the test gel colour changed from yellow to red within 20 min, up to a maximum of 60 min (as recommended by the manufacturer), the sample was considered positive for H pylori.

Statistical analysis
Statistical analysis of data was performed with GraphPad software (InStat, USA).The c 2 test was used to analyze the association between the detection frequencies of H pylori in the dental plaque of patients with and without periodontitis, and the presence or absence of H pylori in the stomach.P<0.05 was considered statistically significant.

RESULTS
A total of 101 subjects with a mean (± SD) age of 40.77±14.15years consented and were selected for the study.Of these patients, 56 were men and 45 were women.All patients were subjected to periodontal examination.Sixtytwo participants (61%) were diagnosed with periodontitis and 39 (39%) had healthy oral cavities (Table 1).
The prevalence of H pylori in the dental plaque of the study cohort was 65% (Table 2).Patients with periodontitis had a significantly higher rate of H pylori-positive test results (79%), compared with only 43% of patients without periodontitis (P<0.05).
Among all study participants, 50 (50%) harboured H pylori in the stomach (Table 3).The periodontitis subjects had a statistically higher prevalence (60%) of H pylori in the stomach than the nonperiodontitis group (33%).Table 4 shows the prevalence of H pylori in the dental plaque of patients with and without periodontitis who harboured H pylori in the stomach.Twenty-nine (78%) of 37 patients with periodontitis harboured H pylori in their plaque samples.However, only four (30%) of 13 subjects without periodontitis harboured H pylori in their dental plaque, a difference that was statistically significant (P<0.05).

DISCUSSION
The oral cavity provides a gateway between the external environment and the gastrointestinal tract, and it facilitates both food ingestion and digestion.Poor oral hygiene and tooth loss can potentially affect gastrointestinal flora and nutritional status, and consequently be implicated in the development of chronic gastrointestinal diseases (11).Poor dental health, tooth loss or both, have been associated with an increased risk for gastrointestinal malignancies including oral, esophageal and gastric cancers (12)(13)(14)(15)(16). Several studies (4,(17)(18)(19) have suggested that dental plaque is a reservoir for H pylori.The presence of H pylori has been universally associated with chronic gastritis and strongly associated with duodenal ulcers.Studies have also identified the microorganism in dental plaque and saliva, implicating the oral cavity as a potential reservoir for H pylori, or as a possible route of transmission to other sites.Riggio and Lennon (20) studied the presence of H pylori in the subgingival plaque of adult periodontitis patients.They found that 38% of the subjects with deep periodontal pockets were positive for H pylori.In a national survey of 4504 subjects, Dye et al (6) observed that nearly 41% of individuals with periodontitis were H pylori seropositive.Moreover, H pylori was detected in more than 50% of patients with periodontitis who harboured H pylori in their stomach (7).The results of the present study are in agreement with previous studies.Fifty per cent of the study subjects with periodontitis were positive for H pylori in dental plaque.Also, among the subjects who were positive for H pylori in the stomach, 74% had chronic periodontitis.
Conflicting reports exist in the literature regarding the presence of H pylori in the oral cavity and its relation to its presence in the stomach (6,8,9).Asikainen et al (8) were not able to detect H pylori in the subgingival plaque of 336 patients with periodontitis, although no analysis for the presence of this bacteria in the stomach of those patients was performed.In another study, Oshowo et al (9) failed to demonstrate any correlation between the presence of H pylori in the stomach and dental plaque, and suggested that the oral cavity may not be a reservoir for reinfection.These conflicting observations could be attributed to the diversity of the populations studied, sample collection methods or the specificity of the methods used for the detection of H pylori.
Although several studies investigated the prevalence of H pylori in the dental plaque of patients with and without periodontitis, most did not investigate the simultaneous existence of the bacterium in the stomach (6).In the present study, the presence of H pylori was examined in both dental plaque and the gastric mucosa of symptomatic patients presenting to a gastroenterology clinic.A higher number of subjects with periodontitis had a coexistent presence of the bacterium in the stomach and in dental plaque compared with nonperiodontitis patients.The significantly higher prevalence of H pylori in the periodontitis group may be related to poor oral hygiene and the presence of periodontal pockets.Miyabayashi et al (3) suggested that H pylori in dental plaque may be a risk factor for recurrent gastric infection.The results of the current study support this suggestion and highlight the importance of the oral cavity and dental plaque as reservoirs for H pylori as a potential source for reinfection after eradication treatment.A combination of professional medical and dental treatment modalities may be required for individuals with H pylori infection.