Evaluation of the effect of different Ni-Ti shaping systems on operation time and postoperative pain in single visit non-surgical retreatment: A randomized clinical trial

Aim: The aim of this randomized clinical trial is to evaluate efficiency of the removal of root canal filling materials by two different Ni-Ti retreatment systems, and final shaping with either reciprocal or rotary shaping systems, on operation time and the incidence of postoperative pain. Material and Methods: One hundred patients aged between 18 and 65 years with asymptomatic mandibular first molars with no spontaneous pain or swelling, who had received endodontic treatment at least 2 years ago but still had radiologic endodontic problems, were randomly and equally divided into four groups. In this study, ProTaper Universal Retreatment file system (Dentsply Maillefer, Ballaigues, Switzerland) was used in the first group (Group 1) for root canal filling removal. In the second group (Group 2), the root canal filling was removed using the MicroMega REMOVER (Coltene/Whaledent, AG, Altstätten, Switzerland) single file Retreatment system. Apical patency was established and maintained with size 10 K- file. Final shaping was completed using the ProTaper Next Rotary (Dentsply Maillefer) rotary file system (Group 1a/2a) or the MicroMega One RECI (Coltene/Whaledent) reciprocal single file system (Group 1b/2b). Operation time was recorded for each group. Post-operative pain values were recorded at 6, 12 hours and on days 1-2-3-4-5-6-7 using a visual analog scale (VAS). At the end of both day 2 and day 7, patients were invited to the clinic and the presence of pain was checked. The day and frequency of analgesic use was recorded on the form. Statistical analysis of the data was performed. Results: There is a statistically significant difference in VAS scores between the REMOVER/PTN (Group 2a) group and PTUR/OR (Group 1b) group only at 48 hours (p<0.05). There is no statistically significant difference in VAS scores at all other times and between all groups (p>0.05). Although not statistically significant, the pain values of Group 1b were higher than the other groups for 7 days. No flare-up case observed in any of the groups. When the relationship between age and postoperative pain was evaluated, a significant difference was observed at 6 hours, 5 days, 6 days and 7 days (p<0.05). At 6 hours, patients over 50 years of age had significantly less pain than the other groups (p<0.05). On day 5, day 6 and day 7, patients over 50 years of age had significantly more pain than patients under 30 years of age (p<0.05). When the relationship between gender and postoperative pain was evaluated, female patients had higher values than male patients in all groups at 24 and 48 hours and on day 3 (p<0.05), while there was no significant difference between genders at other measurement times. When the relationship between operation time and postoperative pain was evaluated, it was found that there was a significant negative relationship between operation time and VAS score only in Group 1b group at 48 hours (p<0.05), while there was no significant relationship in other groups and at all measurement times (p>0.05). When the relationship between operation time and postoperative pain was evaluated, it was found that there was a significant negative correlation between operation time and VAS score at 48 hours only in Group 1b group (p<0.05), while there was no significant relationship in the other groups and at all measurement times (p>0.05). There is a statistically significant difference between the REMOVER/PTN (Group 2a) group and the REMOVER/OR (Group 2b) group in terms of operation times (p<0.05), while there is no statistically significant difference between the other groups (p>0.05). Conclusions: In conclusion, the data of our study showed similar incidence of pain in different groups in terms of postoperative pain, indicating that all four Ni-Ti rotary file systems are clinically preferable in retreatment cases in terms of postoperative pain values.