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

Abstract

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.