Efficacy of D-RaCe and ProTaper Universal Retreatment NiTi instruments and hand files in removing gutta-percha from curved root canals - a micro-computed tomography study

Rödig T, Hausdörfer T, Konietschke F, Dullin C, Hahn W, Hülsmann M. Efficacy of D‐RaCe and ProTaper Universal Retreatment NiTi instruments and hand files in removing gutta‐percha from curved root canals – a micro‐computed tomography study. International Endodontic Journal, 45, 580–589, 2012. Aim To compare the efficacy of two rotary NiTi retreatment systems and Hedström files in removing filling material from curved root canals. Methodology Curved root canals of 57 extracted teeth were prepared using FlexMaster instruments and filled with gutta‐percha and AH Plus. After determination of root canal curvatures and radii in two directions, the teeth were assigned to three identical groups (n = 19). The root fillings were removed with D‐RaCe instruments, ProTaper Universal Retreatment instruments or Hedström files. Pre‐ and postoperative micro‐CT imaging was used to assess the percentage of residual filling material as well as the amount of dentine removal. Working time and procedural errors were recorded. Data were analysed using analysis of covariance and analysis of variance procedures. Results D‐RaCe instruments were significantly more effective than ProTaper Universal Retreatment instruments and Hedström files (P