Evaluation of the Self-Adjusting File system (SAF) for the instrumentation of primary molar root canals: a micro-computed tomographic study

Authors:

ABSTRACT

Aim

The Self-Adjusting File (SAF) system has been recommended for use in permanent teeth since it offers more
conservative and effective root-canal preparation when compared to traditional rotary systems. However, no study had evaluated the
usage of SAF in primary teeth. The aim of this study was to evaluate and compare the use of SAF, K file (manual instrumentation) and
Profile (traditional rotary instrumentation) systems for primary-tooth root-canal preparation in terms of instrumentation time and amounts
of dentin removed using micro-computed tomography (μCT) technology.

Methods

Study Design: The study
was conducted with 60 human primary mandibular second molar teeth divided into 3 groups according to instrumentation technique:
Group I: SAF (n=20); Group II: K file (n=20); Group III; Profile (n=20). Teeth were embedded in acrylic blocks and scanned with a
μCT scanner prior to instrumentation. All distal root canals were prepared up to size 30 for K file,.04/30 for Profile and 2 mm
thickness, size 25 for SAF; instrumentation time was recorded for each tooth, and a second μCT scan was performed after
instrumentation was complete. Amounts of dentin removed were measured using the three-dimensional images by calculating the
difference in root-canal volume before and after preparation. Data was statistically analysed using the Kolmogorov-Smirnov and
Kruskal-Wallis tests.

Results

Manual instrumentation (K file) resulted in significantly more dentin removal when compared to rotary
instrumentation (Profile and SAF), while the SAF system generated significantly less dentin removal than both manual instrumentation
(K file) and traditional rotary instrumentation (Profile) (p<.05). Instrumentation time was significantly greater with manual instrumentation when compared to rotary instrumentation (p<.05), whereas instrumentation time did not differ significantly between the Profile and SAF systems.

Conclusion

Within the experimental conditions of the present study, the SAF seems as a useful system for root-canal
instrumentation in primary molars because it removed less dentin than other systems, which is especially important for the relatively
thin-walled canals of primary teeth, and because it involves less clinical time, which is particularly important in the treatment of
paediatric patients.

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