Abstract
This systematic review aimed to evaluate the association between Helicobacter pylori in the oral cavity as an extragastric reservoir and oral diseases in patients with or without gastritis. Following the PRISMA guidelines, a comprehensive search was conducted on the PubMed, Scopus, Cochrane Central, and Embase databases (2010-2025) using MeSH terms and keywords related to H. pylori, the oral cavity, and oral diseases. Inclusion criteria included observational studies, clinical trials, and case-control studies. Data extraction and quality assessment were performed using the Newcastle-Ottawa Scale (NOS). Of the 298 records initially identified, 22 studies met the inclusion criteria. The presence of H. pylori in the oral cavity (plaque, saliva) was variably associated with gastritis, periodontitis, dental caries, and halitosis. Detection rates varied widely (0-100%), influenced by methodological differences (PCR, culture, antigen tests). Some studies reported an improvement in oral health after eradication therapy, while others found no significant association. The oral cavity may serve as a reservoir for H. pylori, with implications for oral and systemic health. Standardized diagnostic methods and integrated treatment approaches (combining gastric eradication and oral hygiene) are needed to clarify their role and optimize clinical outcomes. Further research is warranted to establish causal relationships and therapeutic strategies.