Dental plaque as an extra-gastric reservoir of Helicobacter pylori: A systematic review and meta-analysis

Objective: This systematic review and meta-analysis (SRMA) aimed to determine whether the presence of H. pylori in dental plaque is associated with gastric H. pylori infection.

Design: Search for the relevant literature was done in various databases: PubMed, Embase, Web of Science and Cochrane till September 21, 2023. The studies were screened for outcome of interest i.e. gastric H. pylori infection and exposure of interest i.e. H. pylori positivity in dental plaque. The pooled results of the study outcomes were evaluated using Odds Ratio (OR), accompanied by a 95 % confidence interval (CI). To evaluate the heterogeneity among studies, I² statistics were utilized, with an I² exceeding 50 % indicating a significant to high variation. In cases where I² was greater than 50 %, a random-effects model (specifically, the Der Simonian and Laird method) was employed.

Results: Data from 27 observational studies and 2408 participants were included. The pooled OR of the H. pylori positivity in dental plaque among the patients with H. pylori positivity in stomach was 3.80 (95 % CI 2.24; 6.43), with high heterogeneity (I²= 69 %, p<0.01). Sensitivity analysis after removing the outliers reduced the heterogeneity significantly (I²=22 %, p=0.16). Meta-regression revealed that the strength of association did not vary according to the year of study or the sample size included in the studies. Overall certainty of the evidence was low.

Conclusions: The present meta-analysis showed that the presence of gastric H. pylori infection was higher among patients with H. pylori in dental plaque compared to patients without H. pylori in dental plaque. Presence of H. pylori infection in dental plaque can have implications in the management of H. pylori infection as dental plaque can serve as a reservoir from which the microorganism can recolonize the gastric mucosa.