Dentine-removing characteristics of K-files energized by the Piezon-Endo

This in-vitro study evaluated the pattern of dentine removal when a size 25 K-file energized by the Piezon-Endo was applied to flat surfaces of dentine under standardized conditions. The effects of power setting, interfacial force between file and dentine, direction of file oscillation and operator-assisted movement were examined. Vinyl polysiloxane impressions of the instrumented surfaces revealed characteristic patterns consisting of a series of oblique crests, similar to those observed in a previous study using the Cavi-Endo. Each crest was parallel to the next and separated by a relatively constant distance. These crests were disposed along the line of contact with the file. The Reflex microscope was used to determine the height, width and separation of these crests. There were differences in the amount and pattern of dentine removal compared with the study on the Cavi-Endo. When the file was held against the dentine surface using the minimum power setting and an interfacial force of 30 g, the pattern of dentine removal was very similar to that produced by the Cavi-Endo. Increasing the power setting to the maximum recommended for endodontics produced a slight but statistically non-significant increase in dentine removal. Further increase of the power setting to the absolute maximum produced significantly deeper and wider areas of dentine removal by the apical part of the file.(ABSTRACT TRUNCATED AT 250 WORDS)