Effects of denture adhesives on the pathogenicity of Porphyromonas gingivalis

Abstract

Denture adhesives improve denture retention, stability and masticatory function. However, the effects of denture adhesives on oral microorganisms have not been elucidated. This study aimed to investigate the effects of three different forms of denture adhesives （cream, powder and cushion forms） on the pathogenicity of Porphyromonas gingivalis. To this end, the number of adherent P. gingivalis, scanning electron microscope （SEM） images of biofilm formation on the surface of specimens, and gingipain activity were examined. In this in vitro study, P. gingivalis strain ATCC33277 suspension was seeded on acrylic resin and each type of denture adhesive, and incubated for 2 hours at 4 ℃. The number of P. gingivalis adherent to the resin/ denture adhesives was quantified using a quantitative real-time PCR assay. Then, to simulate conditions of use for denture adhesives, the specimens of adherent P. gingivalis were incubated for 1，2，3，6，12 and 24 hours at 37 ℃ in ABCM medium. The number of adherent P. gingivalis at the end of each incubation period was quantified, and the surfaces of the specimens were examined under a SEM. Gingipain activity was examined using a fluorescence assay. The degree of initial adhesion was significantly higher with cream and powder adhesives. The number of adhered P. gingivalis increased with time, however, the slower growth rate was shown after an incubation period of 12 hours. In cream and powder adhesives, biofilm formation was observed by SEM. For all the denture adhesives, high Arg-gingipain activities were observed after 6 hours. Our results indicate that denture adhesives likely enhance the pathogenicity of P. gingivalis.