(PR139) The Disinfection Efficacy of Hypochlorite vs. LEAP in a Complex Biofilm Model

Objective: This study aims to compare the efficacy of sodium hypochlorite (NaOCl) and LEAP (L) against a complex biofilm model of Enterococcus faecalis and Staphylococcus aureus on dentin disks and in a tooth model. Materials &

Methods: 30 coronal dentin slices and 24 mandibular premolars with a single canal were enlarged to the same size and autoclaved. Samples where then incubated with E. faecalis and S. aureus for 21 days. Teeth and disks were randomly divided into 3 groups each (8 teeth and 10 slices per group) and disinfected with Hypochlorite or LEAP (L). Bacterial culture sampling was done for all specimens before (S1) and after (S2) disinfection. 5 slices were selected randomly from each group stained using live/dead bacteria stain and analyzed using confocal laser scanning microscopy (CLSM).

Results: All S2 samples showed significant bacterial reduction compared to S1 (p < 0.05). In the dentin disk model, bacterial reduction in the NaOCl and the Leap group were 99.97% and 99.91%, respectively. In the tooth model, bacterial reduction in the NaOCl and the Leap groups were 99.93% and 99.94%, respectively. CLSM analysis demonstrated various degree of root canal disinfection at the different canal levels.

Conclusion: Both disinfection methods successfully allowed for reduced the number of viable bacteria in both the dentin slice model as well as the tooth model.