Evaluation of the shaping effectiveness of different rotary file systems in primary molars

The purpose of this in vitro study was to assess whether the effectiveness of root canal preparation of primary molar teeth performed with stainless steel K- files, OneShape, Hyflex EDM and EndoArt Pedo Blue file rotary systems differ in terms of change in volume, uninstrumented area and apical transportation with the use of micro-CT scans. A sample size of 60 (n=15) was determined. The samples were collected from the department of paediatric dentistry at Yeditepe University, Dental Faculty, Istanbul based on the inclusion and exclusion criteria. Maxillary and mandibular primary first and second molars unrestorable intraorally purposes extracted due to chronic apical periodontitis and abscess and for reasons not related to this study were used for this experiment with gained consent. The samples were scanned with a desktop micro-CT scanner (SkyScan1275; Bruker micro-CT, Kontich, Belgium) to generate 3D images. Among the 4 experiment groups, there was no statistically significant difference in pre- and post-instrumentation canal volumes and change in canal volume (p>0.012). Furthermore, highest percentage of uninstrumented area was in the Hyflex EDM group (24.5%±24.6), however there was no statistically significant difference between the groups. Apical transportation showed significant difference. It was found that the statistical difference was between the EndoArt group and K-files and also between OneShape and K-files (p<0.012), where the apical transportation value of K-files was significantly smaller. To conclude, all instruments tested in this study could safely shape curved and narrow root canals of primary molars, however with OneShape and EndoArt files causing more transportation compared to hand-files.