Effect of ambient light and bit depth of digital radiograph on observer performance in determination of endodontic file positioning.
OBJECTIVE
To examine the effects of the luminance and bit depth of digital image on observer performance for determination of endodontic file positioning.


METHODS
Using extracted premolar teeth, no. 08 K-file was placed into the canal and positioned so that the tip was either flush or 1 mm short of the radiologic root apex. The samples were imaged with both conventional and digital radiographs at 8 and 12 bits. Eleven observers read the images under dark and bright condition, and receiver operating characteristics analysis was performed. Additionally, the interpreting time was measured.


RESULTS
The 12-bit images showed similar observer performance compared with conventional images, and better than the 8-bit images. The interpretation time for bright condition and 8-bit images was longer than for dark condition and 12-bit images.


CONCLUSIONS
Twelve-bit digital images were preferred to 8-bit for accurate determination of endodontic file position.
Heo
Min-Suk
MS
Department of Oral Radiology, BK21, and Dental Research Institute, College of Dentistry, Seoul National University, Seoul, South Korea.
Han
Dong-Hun
DH
An
Byung-Mo
BM
Huh
Kyung-Hoe
KH
Yi
Won-Jin
WJ
Lee
Sam-Sun
SS
Choi
Soon-Chul
SC
D000704:Analysis of Variance; D001641:Bicuspid; D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging*; D006801:Humans; D008029:Lighting; D015588:Observer Variation; D009811:Odontometry; D012372:ROC Curve; D019252:Radiography, Dental, Digital; D011873:Radiology Information Systems; D015203:Reproducibility of Results; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods