The adoption of nickel-titanium rotary instrumentation increases root-filling quality amongst a group of Swedish general dental practitioners.

The aim of the present study was testing the hypothesis that the adoption of nickel-titanium rotary instrumentation (NTRI) will improve the technical quality of root-fillings. The investigation was carried out within a mandatory continuing education program (CEP) for general dental practitioners (GDPs). The study was conducted amongst GDPs employed by the Public Dental Health Service in the County of Stockholm. Identical questionnaires were distributed before the CEP (Pre-Q) and 9 to 12 months after the course (Post-Q). The CEP consisted of two parts: lectures and hands-on training. From each GDP, radiographs of two cases completed before the course and two cases treated 9-12 months after the course were randomly selected. Primarily molars were selected for evaluation. The radiographs were individually evaluated by two endodontists. Teeth treated before and after training were presented in random order. Adoption rate of NTRI increased from 35% to 75%. Cases from 124 GDPs were included in the final analysis. The rate of good quality root-fillings increased from 27% to 49% (p<.001). A significantly increased radiographic quality was found between GDPs adopting NTRI and those who did not. The GDPs produced root-fillings of very poor quality before as well as after the training period. However, the rate decreased from 29% to 12% amongst adopters and from 46% to 28% amongst non-adopters. Dentists considering canal preparation and root-filling as "easy" produced more frequently good quality root-fillings than the others (p<0.05). In conclusion, the results of the present study were in favour of the idea that a shift to NTRI increases the technical quality of root-fillings produced by GDPs. However, adopters still produce root-fillings of very poor quality. This important issue needs to be addressed in future studies.