Basic ResearchThe Self-adjusting File (SAF). Part 3: Removal of Debris and Smear Layer—A Scanning Electron Microscope Study
Section snippets
Selection of Teeth
Twenty-three single-rooted teeth were selected from a random collection of human teeth that were extracted within the last 3 months and stored in 10% buffered formalin until they were used. Each root was radiographed in buccolingual and mesiodistal projections to evaluate the shape of the root canal and to detect any possible obstruction. The inclusion criteria were single-rooted teeth with straight root canal and an intact pulp chamber, whereas the exclusion criteria were previous root canal
Examiner Agreement
Initial independent agreement of all three examiners was 78% and 58% for debris and smear layer scores, respectively. As for debris scoring, in an additional 17% of the cases, there was initial agreement between two examiners and in only 5% of the cases was there a difference between examiners by more than one level of scoring. When scoring smear layer, in an additional 22% of the cases, there was agreement between two examiners, and in no case was the difference between the examiners by more
Discussion
The SAF, as any mechanical device that is designed to remove dentin layers, produces a smear layer when operated in conjunction with sodium hypochlorite alone 15, 16. This occurred despite the continuous irrigation method used by the SAF (Fig. 2A). Nevertheless, the application of an irrigation protocol with alternating administration of 3% sodium hypochlorite and 17% EDTA rendered the root canal dentin surface free of the smear layer. Similar results could also be achieved in the coronal and
Conclusions
The SAF, operated with the continuous flow of irrigants alternating between sodium hypochlorite and EDTA, resulted in root canals that were free of debris and almost completely free of the smear layer.
The results were better than those previously published for the coronal and midroot portions of the root canal.
The difference was also pronounced in the apical third of the canal, in which previously published protocols failed to adequately clean the canal, whereas the SAF protocol resulted in
Acknowledgments
The excellent SEM work of Mr. Jacob Delarea from the Electron Microscopy Unit, Tel Aviv University, Tel Aviv, is gratefully acknowledged. In addition, the expert technical assistance of Mr. Eltanani Moshe was essential for this study and is gratefully acknowledged.
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Cited by (0)
Dr. Ehud Teperovich, Dr. Raphaela Cohen, and Dr. Raviv Zary are employed by ReDent-Nova, manufacturer of the SAF file. Dr Zvi Metzger serves as a scientific consultant to the same company.