Usage of NiTi rotary instruments for root canal retreatment procedures: Experience and practice of dental practitioners and endodontists

Aim: To investigate the preferences and experiences of general dental practitioners (GDPs) and endodontists in using nickel-titanium rotary instruments (NiTi-RIs) for root canal retreatment (RCR) and to explore the influencing factors. Materials and Methods: Following a pilot study, the final questionnaire comprised 43 questions. The sample size was calculated considering 90% power calculation, dentists' population (n = 7050), and worst accepted response rate of 48%. The electronic questionnaire was emailed to 600 GDPs and all endodontists in Saudi Arabia (n = 175). A reminder email was sent after 8 weeks. Responses were collected, and data were analysed using the chi-square test at P = 0.05. Results: The overall response rate was 53.2%. The highest proportion of respondents (74.4%) used NiTi-RIs for RCR; with a greater proportion of endodontists (88.2%) compared to GDPs (66.2%) [P < 0.001]. The most common reason for not using NiTi-RIs was unavailability (52.4%). The proportion who used conventional NiTi-RIs for RCR (61.3%) was greater than those who use specially designed NiTi-RIs (38.7%) [P < 0.001]. More endodontists (52.2%) used specially designed NiTi-RIs compared to GDPs (33.3%) [P = 0.016]. 68.6% and 53.9% of participants experienced complications when using conventional and specially designed NiTi-RIs, respectively. While fracture of conventional NiTi-RIs was the most common complication (44.6%), ledge formation was the most common one while using specially designed NiTi-RIs (47.9%). Conclusions: Results indicate common incorporation of NiTi-RIs into RCR procedures among GDPs and endodontists. Unavailability is the main limitation, whereas instrument fracture and ledge formation are the most common complications while using conventional and specially designed NiTi-RIs, respectively.