The goal of this comprehensive review was to verify if the prevalence of Helicobacter pylori (Hp) bacteria in patients with dyspepsia is higher in the oral cavity of periodontal or non-periodontal patients. The bibliographic search was conducted on scientific studies published in PubMed, Cochrane Library, SciELO, and BVS. The focus question was: "In patients with dyspepsia and periodontitis, is the prevalence of Hp bacteria in the oral cavity higher than in patients with only dyspepsia or without any disease?" The inclusion criteria were human studies in English, Portuguese, or Spanish languages, published between 2000 and 2022, that included patients over the age of 18 and aimed to evaluate the presence of Hp bacteria in the oral cavity and in the protective mucosal layer of the gastric lining of patients with the diseases (periodontitis and dyspepsia) or without disease; clinical trials, randomized controlled clinical trials, comparative studies, case-control studies, cross-sectional studies, and cohort studies. The methodological quality evaluation of the included articles was performed using the Joanna Briggs Institute tools. The final scores could be of "Low" quality (at least two "no" [red] or ≥ five "unclear" found), "Moderate" quality (one "no" [red] was found or up to four "unclear" criteria were met), or "High" quality (all green [yes] or at maximum two "unclear"). Of 155 potentially eligible articles, 10 were included in this comprehensive review after the application of the eligibility criteria. The selected studies were scrutinized regarding the relationship between Hp colonization in the oral cavity and stomach, its impact on severity and complications of gastric infection, as well as the effect of the presence of oral and gastric Hp on dental and systemic parameters. Hp can colonize periodontal pockets regardless of its presence in the stomach. There was a higher prevalence of oral biofilm in dyspeptic patients with periodontal disease, and worse control of bleeding and low oral hygiene was observed in periodontal compared to non-periodontal patients. For que quality assessment, the scientific studies included presented low to moderate methodological quality. Conclusions: It is possible to conclude that Hp is a bacterium that can colonize dental plaque independently of the stomach and vice versa; however, when both diseases are found, its presence may be more significant. Supra and subgingival dental plaque may be a reservoir of Hp, suggesting that patients with gastric infections are more likely to have Hp in the oral cavity. The results must be carefully analyzed due to the limitations present in this review.
Keywords: Helicobacter pylori; bacteria; dental plaque; dyspepsia; periodontal disease; periodontitis.