Comparative evaluation of cleaning efficacy and microbial load reduction in primary teeth using three different rotary file systems: an in-vitro study

Dental caries in primary teeth is highly prevalent and may progress to pulpal and periapical pathology if untreated. Pulpectomy is indicated to eliminate infection and preserve the tooth until natural exfoliation. Its success relies on effective cleaning, shaping, and disinfection of the root canal system. However, the complex anatomy of primary teeth and resistant microorganisms such as Enterococcus-faecalis make complete debridement difficult. With the advent of newer pediatric rotary file systems, their cleaning and antimicrobial efficacy requires evaluation. To evaluate and compare the cleaning efficacy and microbial load reduction of three rotary file systems in extracted primary teeth. Forty-eight extracted primary molars were selected and randomly divided into two groups (n = 24 each). Group I assessed cleaning efficacy using India ink removal under a stereomicroscope at coronal, middle, and apical thirds with a fourpoint scoring system. Group II evaluated antimicrobial effectiveness against Enterococcus-faecalis. Samples were inoculated, incubated, and instrumented using respective rotary systems. Microbial load was measured before and after instrumentation using colony-forming units (CFUs). Statistical analysis determined intergroup differences. No significant difference was found in the coronal third (p = 0.277). Significant differences were observed in the middle (p = 0.012) and apical thirds (p = 0.043), with XP Endo® Shaper showing superior cleaning efficacy. All groups demonstrated significant microbial reduction (p < 0.001). XP Endo® Shaper showed the highest reduction (58.58%), followed by Kids-e-files (50.76%) and Kedo Nano (37.58%). XP Endo® Shaper performed significantly better than Kedo Nano. All systems were effective; however, XP Endo® Shaper showed superior cleaning and microbial load reduction performance. Complete canal disinfection remains challenging, emphasizing the importance of adjunctive irrigation protocols.