| Popis: |
Background: The aim of the present study was to evaluate the canal transportation and centering ability of ProTaper, HeroShaper and two Ni-Ti rotary systems developed for retreatment (ProTaperRetreatment and R-Endo). Materials and Methods: One hundred twenty mesial canals of mandibular molars with curvatures between 30-40 degrees and radii of curvatures between 4-9 mm were embedded in a modified muffle system. The teeth were randomly divided into 8 groups (n=15). The roots were sectioned horizontally at 3, 6 and 9 mm from the working length. Cross-sections were digitally photographed under standardized conditions. Half of the root canals were prepared with ProTaper and the rest with HeroShaper. Postoperative photographs were obtained. Root canals were obturated with the respective gutta-percha cones of the systems and AHPlus sealer. Following retreatment with four systems, photographs were assessed for the canal transportation in 8 directions, and centering ratio. Results: Initial shaping with ProTaper resulted in more significant transportation than HeroShaper (p |
