A micro-computed tomographic assessment of root canal preparation with conventional and different rotary files in primary teeth and young permanent teeth

Background Root canals of primary teeth are commonly prepared with endodontic files that are originally manufactured for permanent teeth. Aim This micro-computed tomography (micro-CT) study evaluated and compared the changes in root canal morphology after preparation with different conventional and rotary files in primary teeth and young permanent teeth. Design Seventy-two extracted primary and permanent molars were selected and randomly assigned to three subgroups according to the file systems used (n = 12/each). After pre-scanning of teeth with micro-CT, root canals were prepared with One Shape and Revo-S rotary systems and conventional endodontic files. After rescanning procedure, changes in canal volume, surface area, uninstrumented surface area, and apical transportation were evaluated. Mann-Whitney U test, Kruskal-Wallis test, and Conover's multiple comparison test were used for statistical analysis (P = .05). Results Instrumentation with rotary files resulted in significantly greater volume and surface area of root canals and less uninstrumented areas (P < .001) than with manual files (P < .001). Primary molars showed significantly less apical transportation than permanent teeth (P < .001). Conclusions Preparation of canals with rotary files could be a viable alternative to conventional files in primary teeth. Regardless of the file system used, uninstrumented areas still exist in both primary teeth and permanent teeth.