(PR21) Bacterial Reduction After the Use of Ultrasonics and GentleWave: an In-vitro Study

Numerous studies have shown that E. faecalis is the most commonly found species in endodontically treated teeth exhibiting persistent disease. The aim of this study is to compare the efficacy in bacterial reduction of passive ultrasonic irrigation (PAU) and the Gentlewave multisonic system (GW). In this pilot study, five freshly extracted molars were accessed and the mesial canals instrumented to a size 25/.04 (Vortex Blue). Teeth were autoclaved and subsequently infected with E. faecalis for four weeks. Following the incubation period, sample 1 (S1) was obtained using a #30 Hedstrom file to create dentin debris and collected with sterile paper points. The sample was serially diluted, plated, incubated for 24 hours, and the number of colony forming units counted. Three teeth served as positive controls, one of them was analyzed under scanning electron microscope. Remaining infected molars (n=2) were randomly separated into two treatment groups: Ultrasonic or GentleWave. Samples were irrigated using the designated protocols and sample 2 (S2) was immediately collected and processed as previously described. Lastly, a diamond disk was used to section the mesial roots into three segments. Coronal, middle, and apical segments were processed to obtain pulverized dentin and cultured for comparison. There was no bacterial growth within the root canal and dentinal tubules following the irrigation protocols in either treatment group while the positive controls behaved as expected. Within the limitations of this study, it can be concluded bacterial reduction in mesial roots of mandibular molars is similar with ultrasonics and GentleWave irrigation systems.