Comparison of disinfection effectiveness through manual instrumentation, rotary system and photodynamic therapy in primary molars: An in vitro study

Abstract

Aim: Due to the particular anatomy of primary teeth, improvements in the materials and protocols used for disinfecting and modelling the root canal system are needed to develop a more objective and efficient approach. The aim of this in vitro experimental study was to compare the disinfection of the root canal system of primary teeth with manual, rotary and photodynamic therapy systems. Methods: Forty-eight canals of primary molar teeth were infected with a suspension of Enterococcus faecalis and divided into four groups (n = 12): group G1, composed of canals prepared with manual H-type files from the Angelus® system via the crown-down technique; group G2, treated with the Sequence of Baby Files™ rotary system by the pecking motion technique; group G3, using the G2 treatment + photodynamic therapy, with methylene blue as photosensitizer at a concentration of 0.005%, irradiated with a 660 nm diode laser for 100 seconds, 100 mW power, 10 J energy and 357 J/cm² fluence; and group G4 (negative control), which received no treatment. Samples of the canal contents were collected with sterile paper cones before and after instrumentation, diluted and seeded on BHI agar plates. The bacterial colonies formed were counted, and the results were log transformed and subjected to analysis of variance (ANOVA) and Dunnett’s test. Results: Showed a bacterial reduction in all studied groups compared to the control group. Conclusions: We concluded that the manual, rotary and photodynamic therapy systems all significantly reduced the E. faecalis count. Keywords: Deciduous Teeth; Enterococcus faecalis; Root Canal Therapy