The aim of this study was to study the long-term effect on root filling quality after the introduction of nickel titanium rotary instrumentation (NTRI) within a public dental health organization. After an education package, including hands-on training and/or lectures, the root filling quality was evaluated at the organizational level. All general dental practitioners (GDPs) employed at primary evaluation (n = 120) and after 4 years (n = 174) were included. The improved root filling quality had been maintained 4 years later. The frequency of excellent root fillings was slightly higher at the long-term follow-up (52%) compared with the short-term follow-up (45%; P = .038). A nonsignificant decrease in very poor-quality root fillings was registered. A technology shift among GDPs to NTRI will increase the rate of good-quality root fillings. However, the shift per se will not eliminate the problem of substandard clinical performance. Copyright © 2011 Mosby, Inc. All rights reserved.