Innovative treatment against human periodontitis and periimplantitis - in vitro study

Periodontitis (PD) and peri-implantitis (PI) are inflammatory diseases caused mainly by dental plaque, in the structure of which we find numerous bacteria that can cause oral imbalances accompanied even by the loss of teeth or implants. In this study we described the materials and methods used to obtain bacterial lysates from strains of Aggregatibacter actinomycetemcomitans (A.a), Fusobacterium nucleatum (F.n) and Streptococcus oralis (S.o) that induced periodontal and peri-implant disease in the rat model. From 24-hour cultures we obtained the final product after inactivation and mechanical rupture of the bacterial wall. We tested the effect of the bacterial lysate by in vitro tests that involved contacting it with live bacteria in different dilutions. We mimicked the treatment by daily addition of a dose of lysate and monitored the inhibition of bacterial activity. At a second, at least double dose, the results showed that the lysate neutralised the microbial agent in the liquid medium. On solid culture media we could observe the inhibitory effect after the second seeding, i.e. when the inoculum to be cultured contained twice the dose of lysate compared to the live bacteria. We also performed the cytotoxicity test which showed 98% viability of A.a. lysate, 97% of F.n. lysate and 99% of S.o. lysate. The data obtained are valuable but further in vitro tests are needed to standardize the method but also in vivo tests to follow the triggering of the body's immune response and evaluate the immunostimulatory effect of bacterial lysates.