Abstract
BackgroundComplete removal of old filling material during root canal retreatment is fundamental for predictable cleaning and shaping of canal anatomy. Most of the retreatment methods tested in earlier studies have shown inability to achieve complete removal of root canal filling. Therefore the aim of this investigation was to assess the efficacy of three different rotary nickel titanium retreatment systems and Hedstrom files in removing filling material from root canals. Material and Methods Sixty extracted mandibular premolars were decoronated to leave 15 mm root. Specimen were hand instrumented and obturated using gutta percha and AH plus root canal sealer. After storage period of two weeks, roots were retreated with three (Protaper retreatment files, Mtwo retreatment files, NRT GPR) rotary retreatment instrument systems and Hedstroem files. Subsequently, samples were sectioned longitudinally and examined under stereomicroscope. Digital images were recorded and evaluated using Digital Image Analysing Software. The retreatment time was recorded for each tooth using a stopwatch. The area of canal and the residual filling material was recorded in mm2 and the percentage of remaining filling material on canal walls was calculated. Data was analysed using ANOVA test. Results Significantly less amount of residual filling material was present in protaper and Mtwo instrumented teeth (p < 0.05) compared to NRT GPR and Hedstrom files group. Protaper instruments also required lesser time during removal of filling material followed by Mtwo instruments, NRT GPR files and Hedstrom files. Conclusions None of the instruments were able to remove the filling material completely from root canal. Protaper universal retreatment system and Mtwo retreatment files were more efficient and faster compared to NRT GPR fles and Hedstrom files. Key words:Gutta-percha removal, nickel titanium, root canal retreatment, rotary instruments.
Highlights
Long term success of endodontic therapy relies on thorough debridement of the root canal system followed by three dimensional obturation
Complete removal of root canal filling material is of utmost importance in order to achieve effective cleaning and disinfection of canal anatomy [3]
The aim of the current study was to evaluate the efficiency of different rotary instrument systems - Protaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland), MTwo Retreatment system (Sweden and Martina, Padova, Italy) and a new NRT GPR file system (Mani Inc., Japan), compared with manual instrumentation with H-files for gutta percha removal during retreatment
Summary
Long term success of endodontic therapy relies on thorough debridement of the root canal system followed by three dimensional obturation. The aim of the current study was to evaluate the efficiency of different rotary instrument systems - Protaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland), MTwo Retreatment system (Sweden and Martina, Padova, Italy) and a new NRT GPR file system (Mani Inc., Japan), compared with manual instrumentation with H-files for gutta percha removal during retreatment. A relatively new rotary file system for gutta-percha removal, namely the NRT GPR has been manufactured by Mani Inc., which has helical grooves along the working section. It is available in 4 sizes; 1S, 2S, 3N and 4N. Protaper instruments required lesser time during removal of filling material followed by Mtwo instruments, NRT GPR files and Hedstrom files. Protaper universal retreatment system and Mtwo retreatment files were more efficient and faster compared to NRT GPR fles and Hedstrom files
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
