Efficiency of Two Types of Rotary Ni-Ti Retreatment Files in Removal of Gutta-Percha. An In-Vitro Study

Abstract

The clinical success rate of endodontic retreatments has been estimated to vary between 50% and 90%, depending on the effective elimination of necrotic tissue, bacteria, and infected obturation material such as gutta-percha and cements from root canal. [1] [75] [76]

Various nickel-titanium (Ni-Ti) rotary endodontic instruments have been developed to facilitate cleaning and shaping of root canals. In order to improve safety preparation and to prepare more appropriate shapes, advanced instrument designs with non-cutting tips, radial lands, varying tapers and rake angles, and changing pitch lengths have been developed. [22]

This study aimed to compare the efficiency of two Ni-Ti retreatment rotary files (D-RaCe & R-Endo) and the effect of the multiple uses on that efficiency and on the surface topography of the files.

Eighty mesiobuccal canals of mandibular human molars were equally divided between D-RaCe and R-Endo groups, and further subdivision into 2 groups according to the no of uses of the file. Canals were cleaned, shaped and obturated. Retreatment was carried out using D-RaCe and R-Endo.

The roots were then sectioned and the sections with more residual of gutta-percha were examined under stereomicroscope and image analysis was carried out to calculate the percent of the residual filling material surface area.

Also the files that reach the full working length in each group (DR2-R3) were examined under SEM to investigate surface topography.