ACTA FAC MED NAISS 2021;38(3):291-298

 

UDC:615.472:616.314.17/.18
DOI:10.5937/afmnai38-29386

                                             

Original article

 

Ultrastructural Analysis of the Surface Changes on the Nickel-Titanium
Endodontic Instruments after Multiple Use

 

Nenad Stošić1,2, Jelena Popović1,2, Marija Anđelković Apostolović1,3, Aleksandar Mitić1,2, Marija Nikolić1,2, Radomir Barac1,2

 

1University of Niš, Faculty of Medicine, Niš, Serbia
 2Clinic of Dentistry, Department of Restorative Dentistry and Endodontics, Niš, Serbia
 3Medical Statistics and Informatics, Public Health Institute, Niš, Serbia

 

 SUMMARY

          

                                 

               

One of the primary goals in endodontics is efficient cleaning and shaping of the root canal while maintaining its original configuration. Numerous studies highlight the advantage of using nickel-titanium instruments and the most important is their high flexibility and the ability to penetrate the curved canals. The aim of this study was to analyze the ultrastructure of the surface of nickel-titanium endodontic files before and after use. Eighty-four instruments were included in this study. The instruments were used one, three and six times for root canal preparation on extracted upper premolars. The analysis was performed based on the number of uses and the size of the instruments. Changes on flat surfaces in the grooves of the instruments, defects of the cutting edges and fractures were evaluated. The surface ultrastructure was analyzed on a scanning electron microscope (SEM). SEM analysis showed irregularities on the surfaces of the new instruments. Surface defects and damage of the cutting edges were present after the first use. After three uses, the damage was more evident in instruments of all sizes. After six uses, all instruments showed damage of the cutting edges, and a significant number of fractures were observed. Irregularities on the working parts are already noticed on the new endodontic instruments and originate from the production process. The first signs of damage appear after the first use. In order to prevent errors in clinical work during root canal preparation, it is recommended that the number of instruments uses should be limited.

 

Key words: endodontic instruments, nickel-titanium, damages, SEM