Defects Appearing to the Unaided Eye vs. Magnification in a Pediatric Rotary NiTi File

The objective of the study was to examine with the unaided eye, the defects appearing in a pediatric rotary NiTi file following clinical use and compare the observations to examination under magnification. Ten "Pro AF - Gold Baby file number B4" were used in the study. After every clinical use (Maximum five uses), the files were examined by a single observer with the unaided eye for gross distortions. The tip and flutes on each file were then observed under a stereomicroscope at 20× magnification and the defects scored. None of the files showed any distortion when observed with the unaided eye after five clinical uses. Under stereomicroscopic examination, file tips showed no significant difference in the percentage of damaged files compared to the percentage of normal files (files without defects) whereas flutes showed a significant difference (p value 0.031) compared to the percentage of normal files after the second use. The flutes of all the files showed some degree of defect following the third use.We concluded that examination of the Pro AF - Gold Baby file number B4 with the unaided eye is not a reliable indicator of the actual physical state of the file. At the end of five clinical uses, nine files out of ten showed "mild" and one file showed a "severe" defect under magnification. None of the files fractured after five clinical cases. Though the results cannot be extrapolated to other pediatric rotary NiTi file systems, the study provides a strong case for the routine use of dental loupes/magnification in a pediatric endodontic practice.