Background:
The importance of oral microbiota in the context of the patient’s general health is widely known. Over 700 bacterial strains that inhabit niches with different biodiversity have been identified.

Aim of the study:
To compare the composition of the oral and denture microbiota in patients using removable prosthetic restorations.

Material and methods:
The study group included 34 patients using dental prostheses. Each patient underwent an initial examination, including a detailed interview and intraoral examination. Then, a swab was taken from the floor of the mouth and the mucosal surface of the denture using a sterile swab with Amies transport medium with charcoal. The material was delivered to the Microbiology Laboratory of the Department and Institute of Microbiology and Immunology in Zabrze, where laboratory microbiological tests were performed to isolate and identify the bacterial strains present in the samples.

Results:
Of all the strains cultured from samples from each patient, the percentage of strains common to both sampling sites was recorded. Among all patients, the concordance ranged from 0 to 100%, but the average of isolated strains was 34.7%, with a greater diversity noted in samples from the floor of the mouth.

Conclusions:
The results suggest a significant role of saliva and environmental factors on the composition of the oral microbiota. Proper denture hygiene can affect not only the mucosa in direct contact with the denture plate, but also the well-being of the entire oral cavity and, consequently, the whole organism.