Na. Golubow et al., DIRECT DIGITAL RADIOGRAPHY FOR THE DETECTION OF DEFECTS IN A STANDARDALUMINUM TEST OBJECT THROUGH COMPOSITE RESIN RESTORATIVE MATERIALS, Dento-maxillo-facial radiology, 23(2), 1994, pp. 91-96
While the RVG 32000 (Trophy Radiologie, Vincennes, France) is in wide
use for direct digital intraoral radiography in dentistry, there is a
dearth of information in the literature concerning the system's sensit
ivity to small changes in radiographic density consistent with initial
and recurrent dental caries. A standardized 7 mm aluminium test block
was used as a phantom for perceptibility testing of density changes,
both with and without the superimposition of composite resin sheets of
various thicknesses. Defects in the block were randomly positioned an
d varied from 0.1 to 1.5 mm. Thermal prints were used for evaluation.
Standard linear images, with no enhancement, were compared with three
enhanced modes, standard mode with gradient enhancement (enhanced stan
dard), standard X-function and zoom high resolution (ZHR). Sensitivity
improved in the following sequence: standard 0.58 < enhanced standard
0.75 < X-function 0.94 < ZHR 0.95. Accuracy improved in the following
sequence: standard 0.45 < enhanced standard 0.58 < X-function 0.73 <
ZHR 0.74. Specificity was 1.0 both for X-function and for ZHR. These t
wo modes both proved significantly better (P < 0.05) for the detection
of 0.1 mm defects than the other two modes tested. No significant dif
ference was found between X-function and ZHR. As ZHR requires four tim
es the radiation exposure as standard exposures with the X-function, t
he latter is preferred for the task described in this study.