Mechanical bacterial removal of Enterococcus faecalis in distovestibular roots of upper molars between two single-file mechanized preparation systems: an in vitro study

Abstract

Automated single-file systems create predictable preparations, reducing operator and patient workload and stress without neglecting the original anatomy of the canal. The objective of this study was to evaluate the mechanical bacterial removal between two preparation systems, WaveOne Gold and TruNatomy, when instrumenting disto-vestibular roots of upper molars contaminated with Enterococcus faecalis. An experimental in vitro, comparative, and descriptive study was conducted with 32 upper molars, distributed in 4 groups. The roots were sectioned, sterilized, permeabilized, and contaminated with Enterococcus faecalis, incubated at 37°C for 21 days. The samples were then placed in tubes with peptone water and in TSB culture medium at 37°C for 48 hours. The groups were: WaveOne Gold Primary (n=12), TruNatomy (n=12), Positive control (manual technique, n=5), and Negative control (non-contaminated specimens, n=3). The data were processed in Excel 2016 and SPSS 25, and bacterial reduction was evaluated using the Kruskal-Wallis test. The results showed that the survival rate of Enterococcus faecalis in the canals after instrumentation with WaveOne Gold was 5% (95% reduction), with TruNatomy it was 4% (96% reduction), and with manual instrumentation it was 6% (94% reduction). No significant differences were found between the systems (p>0.05), but there were differences in bacterial counts before and after instrumentation (p<0.05). In conclusion, WaveOne Gold and TruNatomy showed similar effectiveness in the removal of Enterococcus faecalis.