Abstract
Introduction: Different irrigation protocols have been developed to improve the efficacy of root canal irrigants. The goal of this investigation was to compare several irrigation protocols for helping irrigation penetration into the dentinal tubule. Materials and methods: Fifty-five extracted single-rooted human lower premolar roots were instrumented to reach size 30 taper .04, sterilized, then inoculated with Enterococcus faecalis for 3 weeks. Teeth were then grouped according to the disinfection protocol into: group A (n=15): canals were disinfected with Diode Laser; group B (n= 15): XP Endo Finisher was used for final irrigation; group C ( n=15): needle irrigation, in addition to two control groups; D (n= 5): canals were irrigated with Saline and E (n=5), no bacteria being inoculated in the canals. The teeth were split into halves and stained with bacterial viability stain, then scanned by confocal laser scanning microscopy to measure the ratio of live vs dead bacteria in the dentinal tubules of the canals, Results and disscusion: A significant difference between the amount of live vs dead bacteria was found among all groups (p<0.05). The XP Endo finisher and Diode laser showed more dead bacteria at all levels. Conclusions: Sodium hypochlorite activation by Diode laser and XP Endo finisher improves disinfection of the root canal at all levels, especially at the apical part. Canals irrigated with the Diode Laser and XP Endo Finisher showed higher bacterial reduction of E. faecalis in dentinal tubules, compared with standard needle irrigation.