Usage Parameters of Nickel-Titanium Rotary Instruments: A Survey of Endodontists in the United States

Introduction: Usage of U.S. endodontists regarding rotary root canal instruments is not well-documented. Therefore, the aim of this study was to retrieve data from a representative sample of endodontists regarding contemporary usage of rotary instruments. Methods: A questionnaire addressing (1) nickel-titanium (NiTi) rotary instrument usage and (2) expectations for future instrument design was constructed. An online survey was e-mailed to 954 endodontists in California (n = 358), Iowa (n = 25), Massachusetts (n = 120), Minnesota (n = 49), New York (n = 217), Texas (n = 144), and Wisconsin (n = 41). Data were collected from respondents by using a web-based interface during a 4-month period. Valid responses were received from 359 endodontists, representing a 38% response rate. Chi-square tests and correlation coefficients were used to analyze the data; the level of significance was set at .05. Results: Usages varied by region, graduation date, and type of practice. Recent graduates were more likely to use NiTi rotary instruments for every treatment (P = .007), multiple NiTi systems (P = .002), torque control motors (P = .03), and Gates Glidden instruments (P = .001) than were older endodontists. More than 50% of respondents used NiTi rotary instruments in several patients before discarding, and 57% reported cleaning the instruments with a combination of ultrasonics and sterilization. Crown-down was the most frequently used preparation strategy. There were few differences regarding geographic regions. More than 70% of respondents expected similar but improved files during the next 10 years. Conclusions: Differences exist among U.S. endodontists regarding current NiTi instrument use, and expectations for future development might be correlated with level of exposure and training