Periodontitis is a chronic degenerative disease which is inflammatory and whose bacteriological aetiology interests the hard and soft tissues supporting the dental elements. A typical characteristic of periodontitis is its correlation with other branches of medicine since periodontal disease is often associated with several other illnesses or systemic conditions which exacerbate or predispose the course of the disease. Amongst the most frequent gastroduodenal diseases are those associated with <i><span>Helicobacter pylori</span></i><span> (Hp) infections such as acute gastritis, chronic atrophic gastritis, gastric atrophy, gastritis ulcers, dysplasia, duodenal ulcer, gastric cancer, gastric MALT-lymphoma. Transmission of the microorganism occurs through iatrogenic pathways (faecal-oral, oral-oral) and through food and water ingestion. From this the possible role of the oral cavity becomes evident as a means of transmitting the microorganism and as an extra-gastric reservoir of Hp which develops inside the oral plaque, the main aetiological agent of periodontal disease. Considering that in a patient affected with periodontal disease the oral cavity presents elevated i</span><span>ndices of bacterial plaque in association with infrabony pockets one is</span><span> brought to ask if it might represent a favourable habitat for Hp colonisation. Furthermore, another query that one might pose is whether the presence of Hp in the oral cavity might be the cause of relapse in gastric infections caused by Hp. Consequently, might non-surgical periodontal treatment, in association with an eradicating gastric therapy, foster decontamination of the microor</span><span>ganism in the oral cavity leading to a better prevention of relapse and</span><span> re-infec</span><span>tion of the gastric cavity? Could non-surgical periodontal treatment thus</span><span> mean prevention of gastric diseases brought on by </span><i><span>Helicobacter pylori</span></i><span>? The objective of this study is therefore to evaluate the incidence of