Objectives: This in vitro study aimed to evaluate and compare the antibacterial efficacy of intracanal heated sodium hypochlorite, cryo-treated sodium hypochlorite and sodium hypochlorite at room temperature with and without passive ultrasonic activation against E. faecalis in single rooted teeth.
Materials and methods: forty-two extracted human single-rooted teeth were prepared by Protaper next rotary system. The teeth were sterilized and inoculated with E. faecalis bacteria for 2 weeks and divided randomly into six groups according to the final irrigation protocol. Group I1, cryotreated NaOCl at 2°C - 4°C, group I2, cryotreated NaOCl with ultrasonic activation, group I3, intracanal heated NaOCl at 180°C by fast pack, group I4, intracanal heated NaOCl with ultrasonic activation, group I5, NaOCl at room temperature with ultrasonic activation, and a control group, NaOCl at room temperature. First sample was taken from each canal before the tested protocols. Second sample was taken after implementing the irrigation protocol using paper points. The number of colonies forming units per milliliter was calculated on the agar medium using unaided eye. Significance level was set at P ≤ 0.05.
Results: Intracanal heated NaOCl with ultrasonic activation showed the highest bacterial reduction, followed by cryotreated NaOCl with ultrasonic activation, intracanal heated NaOCl, cryotreated NaOCl, and NaOCl at room temperature with ultrasonic activation with no significant difference between them ((p > 0.05). NaOCl at room temperature showed significantly the least bacterial reduction than all other groups.
Conclusion: Intracanal heated NaOCl at 180°C with passive ultrasonic activation showed the highest post-irrigation bacterial reduction.